CER

N-T

HES

IS-2

017-

347

241

120

17

No drsquoordre NNT 2017LYSE1240

THEgraveSE DE DOCTORAT DE LrsquoUNIVERSITEacute DE LYONopeacutereacutee au sein de

lrsquoUniversiteacute Claude Bernard Lyon 1

Eacutecole Doctorale ED52Physique amp Astrophysique de Lyon

Speacutecialiteacute de doctorat Physique HadroniqueDiscipline Physique Expeacuterimentale

Soutenue publiquement le 24112017 par TEYSSIER Boris

Light-neutral meson production inpp collisions at

radics = 13 TeV at

forward rapidity in ALICEat the CERN LHC

Devant le jury composeacute de

ERAZMUS Barbara DR-HDR CNRSndashSUBATECH Preacutesidente

ARNALDI Roberta Chercheur INFNndashTorino RapporteureCROCHET Philippe DR-HDR CNRSndashLPC RapporteurBALDISSERI Alberto DR-HDR CEAndashSaclay ExaminateurHANSEN Hubert MC-HDR UCBLndashIPNL Examinateur

CHEYNIS Brigitte CR-HDR CNRSndashIPNL Directrice de thegraveseURAS Antonio CR CNRSndashIPNL Co-directeur de thegravese

Abstract The ordinary matter surrounding us is made of hadrons which in turn arecomposed of quarks and gluons These latter are elementary constituents which cannotbe observed in a free state However it is at present recognized that this matter confinedwithin hadrons can undergo under extreme conditions of high temperature andor highnet baryonic density a transition to a state of deconfined quarks and gluons which iscalled quark gluon plasma

The conditions required to form this quark gluon plasma can be experimentallyachieved using a machine capable of colliding nuclei at very high energies this is partic-ularly the case at CERN where is located the worldrsquos largest and most powerful particleaccelerator the Large Hadron Collider which collided Pb ions at a center-of-mass energyof 276 to 502 TeV per nucleon pair and protons of 09 to 13 TeV Pb-Pb collisions atsuch relativistic energies definitely allow for the suitable density conditions to form thequark gluon plasma phase

This thesis work contributes to this physics program by studying the production ofneutral light mesons in collisions of proton-proton at 13 TeV which provides the necessaryreference to understand further observations done in Pb-Pb collisions This study has beenperformed in the dimuon decay channel by analyzing the dimuon invariant mass spectrumin the region of masses lower than 15 GeVc2 giving access to the measurement of thecross sections of η ρω and φ meson

Keywords CERN LHC ALICE QGP Chirality Muon Meson StrangenessHadronic Physics High Energy Physics

Eacutetude de la production de meacutesons neutres leacutegers dans la voie de deacutesinteacutegrationdimuonique en collisions proton-proton agrave

radics = 13 TeV agrave rapiditeacute vers lrsquoavant

dans ALICE au LHC du CERN

Reacutesumeacute La matiegravere qui nous entoure est formeacutee de hadrons eux-mecircmes constitueacutesde quarks et de gluons Ces derniers sont des composants eacuteleacutementaires qui nrsquoexistentpas sous forme libre Cependant nous savons agrave lrsquoheure actuelle que la matiegravere confineacuteedans des hadrons peut dans des conditions de haute tempeacuterature etou de haute densiteacutebaryonique se retrouver sous une forme deacuteconfineacutee de plasma de quarks et de gluons

Pour reacutealiser expeacuterimentalement les conditions permettant de former ce plasma dequarks et de gluons nous avons besoin drsquoune machine capable de faire entrer en collisionsdes noyaux agrave des eacutenergies tregraves eacuteleveacutees cela est notamment possible au CERN ougrave se situele plus grand acceacuteleacuterateur de particules du monde le Large Hadron Collider qui a permisde faire entrer en collisions des noyaux de Plomb agrave une eacutenergie par paire de nucleacuteonsde 276 et 502 TeV et des protons agrave des eacutenergies allant de 09 agrave 13 TeV Les collisionsentre noyaux de Plomb permettent en particulier drsquoatteindre les conditions de densiteacutedrsquoeacutenergie neacutecessaires agrave la formation de la phase de plasma de quarks et de gluons

Ce travail de thegravese contribue agrave ce programme de physique par lrsquoeacutetude de la productionde meacutesons neutres leacutegers en collisions proton-proton agrave 13 TeV reacutefeacuterence neacutecessaire pourcomprendre les observations en collisions Plomb-Plomb Lrsquoeacutetude des meacutesons neutres leacutegersa eacuteteacute meneacutee dans le canal dimuonique par lrsquoanalyse du spectre de masse invariante desdimuons de masse infeacuterieure agrave 15 GeVc2 permettant notamment de mesurer les sectionsefficaces des meacutesons η ρω et φ

Mots cleacutes CERN LHC ALICE QGP Chiraliteacute Muon Meacuteson Eacutetrangeteacute PhysiqueHadronique Physique des hautes eacutenergies

Remerciements

Je tiens tout drsquoabord agrave remercier lrsquoIPNL sous la direction de Guy Chanfray ainsi quele groupe ALICE de Lyon sous la direction de Brigitte Cheynis pour mrsquoavoir accueillipendant ces trois anneacutees Je tiens aussi agrave remercier le CNRS pour mrsquoavoir permis defaire cette thegravese gracircce agrave leur financement ainsi que le LAVEX LIO (Lyon Institute ofOrigins) de lrsquouniversiteacute de Lyon pour le serveur de calcul du groupe theacuteorie que jrsquoai eulrsquoopportuniteacute drsquoutiliser

Je voudrais remercier Barbara Erazmus qui a bien voulu ecirctre la preacutesidente de monjury de thegravese Roberta Arnaldi et Philippe Crochet pour avoir eacuteteacute mes rapporteurs quigracircce agrave leurs commentaires ont permis drsquoameacuteliorer la qualiteacute de ce manuscrit Merciaussi agrave Alberto Baldisseri et Hubert Hansen qui ont bien voulu ecirctre examinateurs decette thegravese ce qui a contribueacutee agrave lrsquoameacutelioration du document Je voudrais aussi vousremercier drsquoavoir fait le trajet sur Lyon pour avoir assisteacute agrave ma soutenance

Le groupe ALICE de Lyon mrsquoa permis de reacutealiser cette thegravese dans une bonne ambianceJe remercie Brigitte Cheynis ma directrice de thegravese avec qui jrsquoai pu avoir de nombreusesdiscussions que ce sois sur le VZERO pour ma tacircche de service au sein de la collaborationALICE sur des aspects scientifiques de mon analyse ou tous simplement sur lrsquoactualiteacuteainsi que pour les nombreuses corrections orthographiques que ce sois en anglais ou enfranccedilais qursquoelle a apporteacutees agrave mon travail Je tiens aussi agrave remercier Antonio mon co-encadrant de thegravese qui mrsquoa appris la ponctualiteacute italienne avec qui jrsquoai beaucoup apprissur lrsquoanalyse de donneacutees de ma thegravese et avec qui jrsquoai eu de nombreux eacutechangesdiscussionsque se sois scientifiques ou non Je voudrais aussi remercier Cvetan pour toutes lesdiscussions que jrsquoai pu avoir que ce sois sur le VZERO en lien avec ma tacircche de service ousur la physique hadronique et lrsquoexpeacuterience ALICE Ces discussions mrsquoont permis drsquoeacutelargirma vision du domaine Merci aussi agrave Laurent Ducroux pour les eacutechanges en lien aveclrsquoenseignement ainsi que les conseils apregraves mes diffeacuterentes preacutesentations au laboratoireMerci aussi agrave Raphaeumll pour les divers eacutechanges ainsi que sur lrsquoaide apporteacute durant lapreacuteparation de lrsquooral et agrave Massimiliano pour ces quelques mois au laboratoire en tantque nouveau post-doc du groupe ougrave tes conseils et points releveacutes durant ma preacuteparationdrsquooral ont eacuteteacute utile En plus des permanents et post-doc le groupe agrave accueilli des stagiairesdurant ma preacutesence dans le groupe et jrsquoaimerai les remercier pour la bonne humeur etambiance qursquoils sont apporteacutes tous particuliegraverement ceux qui ont cocirctoyeacute mon bureau quece sois pour deux ou six mois merci agrave Thibault Pierre Demongodin Samuel et AlexandreThyvollet ainsi que Pierre-Etienne et Satya pour leur bonne humeur et leur motivationpour participer au tournoi de volley de lrsquoAPPN

Je souhaiterais aussi remercier Hubert et Alexandre Biguet pour leur eacutechanges sur laQCD et la physique hadronique theacuteorique que jrsquoai pu avoir

Je souhaiterai aussi remercier les membres de lrsquoobservatoire des sciences de lrsquouniversqui mrsquoont permis de reacutealiser une tacircche drsquoenseignement pendant deux ans de ma thegravese

vi

Merci agrave Jean-Philippe Perrillat Jean-Franccedilois Gonzalez et Laurent Ducroux pour mrsquoavoirpris dans leur eacutequipe drsquoenseignement cela a eacuteteacute une expeacuterience tregraves enrichissante

I would like to thank all the ALICE collaboration that allowed me to do this thesisand especially I thank all the collaborators who contributed at the lmmumu PAG inparticular Alessandro Di Falco and Ester Casula from the INFN of Cagliari for theirhelp and advice given during the thesis Satoshi Yano from the Hiroshima university forhis contribution of the pp at 13 TeV In addition to the PAG collaborator I would liketo thanks all the DQ people and in particular Diego Laurent Aphecetch and PhilippePillot for their help in the evaluation of the muon arms systematics Martino for all theenriching exchanges on the operation of the ALICE trigger system and the luminosityEvgeny for his response concerning the physics selection and David for the response onthe multiplicity evaluation I would like to thanks Andreas Elena and Marie qualityassurance coordinator with whom I was in contact for my service task for their kindnessand efficiency during the two and a half years or I participated in the QA as well as fortheir understanding on the delays

Cette thegravese mrsquoa permis de mrsquoimmerger dans la communauteacute franccedilaise de la physiquehadronique notamment gracircce aux rencontre QGP France et je voudrais remerciertoutes les personnes avec qui jrsquoai pu avoir de bonnes discussions lors de ces rencontresnotamment les doctorants et post-doc que jrsquoai pu rencontrer Antoine Astrid AudreyBenjamin Emilie Gabriel Gabriele Jana Julien Lucile Maxime Michael et MohamadCette thegravese mrsquoa permis aussi de faire des rencontres enrichissantes durant les diverseseacutecoles que jrsquoai reacutealiseacutes et je souhaiterai remercier les doctorants qui y ont participeacute pourles bons moments passeacutes dans ces diverses eacutecoles

Bien sucircr je souhaite aussi remercier les doctorants qui ont cocirctoyeacute lrsquoIPNL durant cestrois anneacutees notamment Alexandre Biguet Anne-Laure Bertrand Ceacutecile Elvire Eme-line Franccedilois Guillaume Garilot Guillaume Victor Jean-Baptiste Joffrey Lola NicolasBaillot Nicolas Deutschmann Nicolas Galy Pierre Becker Reacutemi et Solegravene En plus desdoctorants que jrsquoai cocirctoyeacutes je souhaiterai aussi remercier Alain Cleacutement David GeoffreyHubert Martin Sylvie et Yoan pour les nombreuses pauses cafeacute pris ensemble durant cestrois anneacutees ainsi qursquoAntoine pour avoir accepteacute drsquoecirctre mon parrain pour ma thegravese

Merci aussi agrave Aureacutelie Camille Eacuteloiumlse Florian et Laurine pour tous les bons momentsque ce sois les midis en soireacutee durant des films ou des sessions jeux Merci aussi agrave Clairepour toutes ces discussions et soutiens mutuel pour nos thegraveses malgreacute le deacutecalage entrela France et le Breacutesil

Enfin jrsquoaimerais remercier ma famille pour leur soutiens durant toute ma formationuniversitaire ainsi que durant ma thegravese Je suis sucircr que mes grands-parents paternel auraieacuteteacute tregraves fiegravere de me voir arriver jusqursquoagrave ce diplocircme eux qui eacutetaient inquiets de savoir sijrsquoy arriverai ainsi que Christian et Thierry mes oncles auraient eacuteteacute fiegravere et auraient aimeacuteme voir agrave ce niveau

Reacutesumeacute

Ce manuscrit sur mon travail de thegravese commence par un premier chapitre sur les motiva-tions physiques du sujet eacutetudieacute tant sur le plan theacuteorique qursquoexpeacuterimental Dans le deux-iegraveme chapitre je traiterai du collisionneur de particules ayant produit les collisions danslrsquoexpeacuterience ALICE utiliseacutees durant lrsquoanalyse preacutesenteacutee dans ce manuscrit La secondepartie de ce chapitre est justement deacutedieacutee agrave lrsquoappareillage ALICE Le troisiegraveme chapitreporte sur la caracteacuterisation du jeu de donneacutees que jrsquoai exploiteacute ainsi que sur lrsquoeacutevaluationde la luminositeacute inteacutegreacutee correspondant agrave cet eacutechantillon Le quatriegraveme chapitre quant agravelui porte sur les simulations Monte-Carlo qui ont du ecirctre faites pour mener agrave bien cetteanalyse Le cinquiegraveme chapitre sur la meacutethodologie utiliseacutee pour extraire de nos don-neacutees les signaux drsquointeacuterecirct Dans lrsquoavant-dernier chapitre le sixiegraveme nous traiterons delrsquoeacutevaluation des quatre sources de systeacutematiques qui impactent notre analyse Le dernierchapitre traitera des reacutesultats que nous avons pu obtenir en termes de sections efficacesde production de meacutesons neutres leacutegers

Cadre Physique (chapitre 1)Le cadre theacuteorique englobant le travail preacutesenteacute dans ce document est la chromodynamiquequantique deacutecrivant lrsquointeraction forte lrsquoune des quatre interactions fondamentales quenous connaissons agrave lrsquoheure actuelle agissant sur les quarks et les gluons par eacutechangede gluons On verra que cette theacuteorie peut srsquoexprimer matheacutematiquement en termes dedensiteacute Lagrangienne De ce Lagrangien peut ecirctre extraite une symeacutetrie particuliegraverementinteacuteressante pour lrsquoeacutetude des meacutesons leacutegers neutres la symeacutetrie chirale qui sera traiteacutee endeacutetails dans ce chapitre introductif De la chromodynamique quantique peut ecirctre extraitun diagramme thermodynamique de la matiegravere hadronique dans lequel deux principalesphases sont visibles la phase ougrave la matiegravere hadronique se condense sous forme de hadronset la phase partonique ougrave est creacuteeacute un plasma de quarks et de gluons (QGP)

Expeacuterimentalement ce diagramme de phases peut ecirctre eacutetudieacute gracircce agrave des acceacuteleacuterateursde particules permettant de faire des collisions cible fixe etou en mode collisionneurDans la seconde partie de ce chapitre je commencerai par introduire quelques variablescineacutematiques drsquointeacuterecirct pour le domaine ainsi que deux concepts geacuteomeacutetriques qui sont lacentraliteacute de la collision deacutetermineacutee par la distance qui seacutepare les centres des deux noyauxet le plan de reacuteaction de la collision Une collision entre deux noyaux comporte plusieurseacutetapes chronologiques notamment la phase de QGP suivie par deux phases hadroniquesdomineacutees respectivement par des collisions ineacutelastiques et eacutelastiques cela engendre desproductions de particules tregraves diverses Dans la suite du chapitre seront parcourus tousles types de sondes inteacuteressantes pour lrsquoeacutetude des collisions drsquoions lourds jrsquoen profiteraipour faire un petit eacutetat de lrsquoart des mesures faites dans les diffeacuterentes voies drsquoobservationBien sucircr les reacutesultats montreacutes le sont seulement agrave titre drsquoexemple et pas de maniegravereexhaustive

La derniegravere section sur les reacutesultats expeacuterimentaux est focaliseacutee sur la productionde dimuons de basses masses dans ALICE qui fait lrsquoobjet de lrsquoeacutetude rapporteacutee dans ce

viii

manuscrit Dans les preacuteceacutedentes eacutetudes lrsquoaccent eacutetait mis sur le meacuteson φ qui est agrave lrsquooriginedu signal le plus facilement observable dans la reacutegion des basses masses Dans notre caslrsquoeacutetude a eacuteteacute porteacutee sur les meacutesons η ρω et φ car la statistique disponible dans le lotde donneacutees eacutetudieacute est suffisante pour extraire les signaux correspondants

LHC et ALICE (chapitre 2)La premiegravere partie du chapitre 2 sera consacreacutee au LHC notamment au complexedrsquoacceacuteleacuterateurs permettant drsquoinjecter au sein du LHC des noyaux ou des protons Onen profitera pour eacutevoquer les sceacutenarios futurs agrave relativement court terme pour le LHC etpour finir cette courte partie les programmes drsquoions lourds au CERN et plus geacuteneacuteralementdans le monde

La seconde partie du chapitre est deacutedieacutee au deacutetecteur ALICE Cette partie peut ecirctregrossiegraverement coupeacutee en deux parties la premiegravere deacutedieacutee au deacutetecteur actuel et son fonc-tionnement la seconde au programme drsquoameacutelioration qui doit deacutebuter agrave la fin du Run 2du LHC

Luminositeacute et Jeu de Donneacutees (chapitre 3)Dans ce chapitre deux points seront eacutevoqueacutes Le premier porte sur les conditions expeacuteri-mentales pour les donneacutees proton-proton agrave 13 TeV prises en 2016 utiliseacutees dans lrsquoanalysedeacutecrite dans ce manuscrit Le second porte sur lrsquoeacutevaluation de la luminositeacute inteacutegreacuteeCette mesure nous permet drsquoeacutevaluer des sections efficaces de production agrave partir des tauxde production connaissant la section efficace associeacutee agrave la condition de deacuteclenchement debiais minimal de lrsquoexpeacuterience et le nombre drsquoeacuteveacutenements de biais minimal eacutequivalent aujeu de donneacutees consideacutereacute dans lrsquoanalyse Ce chapitre ne traitera pas de lrsquoeacutevaluation decette section efficace de biais minimal qui fait lrsquoobjet drsquoune eacutetude agrave part entiegravere non dis-cuteacute dans ce manuscrit et qui sert agrave toutes les analyses Cette section traitera en deacutetailsde la proceacutedure permettant drsquoavoir le facteur de conversion entre le nombre drsquoeacuteveacutenementsanalyseacutes et le nombre eacutequivalent drsquoeacuteveacutenements de biais minimal

Simulations Monte-Carlo (chapitre 4)Ce chapitre est structureacute en deux parties la premiegravere se focalisant sur les meacutesons neutresleacutegers et la deuxiegraveme sur les simulations des processus de charme et beauteacute ouverte

Dans la partie sur les meacutesons on commencera par donner quelques geacuteneacuteraliteacutes surces particules ainsi que sur le geacuteneacuterateur employeacute dans les simulations Puis on traiteradeux cas drsquointeacuterecirct Le premier cas concerne les processus faisant intervenir trois particulesdans lrsquoeacutetat final de la deacutesinteacutegration (deacutesinteacutegration Dalitz) en mettant lrsquoaccent sur leurfacteur de forme Le second cas quandt agrave lui correspond aux deacutesinteacutegrations agrave deuxcorps dans les canaux dileptoniques et plus particuliegraverement dans celui dimuonique

La seconde partie du chapitre est consacreacutee aux dimuons venant des deacutesinteacutegrationsdes saveurs lourdes ouvertes Un dimuon venant des saveurs lourdes ouvertes est deacutefini

ix

comme deux muons produits durant les chaicircnes de deacutesinteacutegration drsquoune paire quark anti-quark charmeacutes ou beaux On verra dans cette section qursquoun impact visible sur le spectreen masse deacutecoule de la distribution cineacutematique initiale du quark beau ou charmeacute gracircceaux comparaisons que nous avons faites avec des simulations utilisant les distributionscineacutematiques de PYTHIA6 et de FONLL Le dernier point eacutevoqueacute dans ce chapitre concernela longueur de chaicircne de deacutesinteacutegration des hadrons charmeacutes et beaux car nous sommesinteacuteresseacutes agrave reproduire les dimuons venant des paires de charme ou de beauteacute qui sontcorreacuteleacutes Une hypothegravese que nous pouvons faire est que plus une chaicircne de deacutesinteacutegrationest longue plus la correacutelation reacutesultante de la paire est amoindrie On montrera que leprofil de longueur de chaicircne de deacutesinteacutegration possegravede une structure relativement complexeet qursquoil y a un impact sur le spectre en masse en ne consideacuterant qursquoun certain intervallede longueur de deacutesinteacutegration

Extraction du Signal (chapitre 5)Dans ce chapitre deux points seront eacutevoqueacutes le premier sera lrsquoeacutevaluation et la soustractiondu bruit combinatoire le second portera sur la proceacutedure utiliseacutee pour extraire le signal

La composante de bruit combinatoire dans les dimuons de signes opposeacutes aussi appeleacutebruit non-correacuteleacute provient de la meacutethode de construction des dimuons Cette meacutethodeneacutecessite la creacuteation de toutes les paires de dimuons possibles dans un eacuteveacutenement Poureacutevaluer cette composante nous employons la technique du mixage drsquoeacuteveacutenements crsquoest-agrave-dire que nous creacuteons agrave lrsquoaide des donneacutees un lot de dimuons qui par construction serontnon-correacuteleacutes en formant chaque dimuon par combinaison drsquoun muon drsquoun eacuteveacutenement avecun muon drsquoun autre eacuteveacutenement La distribution ainsi obtenue est normaliseacutee agrave partir desdistributions de dimuons de mecircmes signes Cette proceacutedure agrave eacuteteacute valideacutee agrave lrsquoaide desimulations Monte-Carlo Une fois la soustraction du bruit faite pour chaque intervalleen pT et y consideacutereacute dans notre analyse nous pouvons passer agrave lrsquoextraction du signal

Pour extraire le signal drsquointeacuterecirct de notre spectre de dimuons correacuteleacutes nous utilisonsune proceacutedure drsquoajustement par minimisation du χ2 Cette proceacutedure est baseacutee sur unefonction servant agrave lrsquoajustement qui est composeacutee des distributions en masse des pro-cessus hadroniques composant notre cocktail hadronique Nous verrons notamment parquel moyen nous arrivons agrave reacuteduire le nombre de degreacutes de liberteacute de notre fonction enasservissant certaines composantes agrave drsquoautres Une grande partie de ce point est consacreacuteeau traitement du continuum correacuteleacute et aux meacutethodes permettant de deacutecrire la forme dela fonction modeacutelisant le continuum correacuteleacute

Eacutevaluation des Systeacutematiques (chapitre 6)Ce chapitre est diviseacute en quatre parties une pour chaque contribution agrave la systeacutematiquede notre analyse

La premiegravere partie traitera de la systeacutematique sur lrsquoextraction du signal et notammentsur lrsquoeacutevaluation de la systeacutematique sur tous les choix que nous avons faits pour reacutealisernotre ajustement Pour cela un ou plusieurs tests sont faits en modifiant agrave chaque foisun seul paramegravetre par rapport agrave notre ajustement de reacutefeacuterence Une fois tous les tests

x

reacutealiseacutes pour un intervalle en pT-y consideacutereacute dans cette analyse on eacutevalue par la meacutethodede deacuteviation standard lrsquoerreur systeacutematique qui en reacutesulte

Les autres parties traiteront de la systeacutematique lieacutee agrave lrsquoestimation du produit delrsquoacceptante geacuteomeacutetrique et de lrsquoefficaciteacute de reconstruction notamment le choix de lrsquoinputcineacutematique pour les simulations Monte-Carlo lrsquoincertitude sur lrsquoefficaciteacute du systegraveme dedeacuteclenchement et sur lrsquoefficaciteacute du systegraveme de trajectographie

Reacutesultats (chapitre 7)Dans ce dernier chapitre avant de parler des reacutesultats nous discuterons la correction dusignal extrait des distributions de masse invariante reconstruit pour lrsquoestimation de lasection efficace de production Nous passerons ensuite aux reacutesultats en preacutesentant et endiscutant la deacutependance en pT et y de la section efficace de production des meacutesons ηρω et φ Les reacutesultats obtenus dans cette analyse seront compareacutes aux preacutedictions desmodegraveles PYTHIA et PHOJET et aux reacutesultats disponibles dans ALICE agrave drsquoautres eacutenergies

Table of contents xi

Table of contents

1 Physics Motivations 111 Theoretical Baseline 1

111 Quantum ChromoDynamics (QCD) 3112 Chiral Symmetry 6113 Hadronic Matter mdash Quark-Gluon Plasma (QGP) 11

12 Heavy-Ion Physics Experimental Program 12121 Relevant Kinematic Variables 13122 Collision Geometry 14123 Evolution of a Heavy-Ion Collision 15124 Experimental Observables of the QGP 16125 Proton-Proton Collisions 22

13 Low-Mass Dimuon Measurements in ALICE 23

2 ALICE at the CERN LHC 2921 The Large Hadron Collider 29

211 The CERN accelerator complex 29212 The LHC schedule 30213 The Experimental Heavy-Ion Program 32

22 A Large Ion Collider Experiment (ALICE) 33221 The Central Barrel 34222 The Forward Detectors 36223 The Muon Spectrometer 38224 The ALICE software framework 40225 The ALICE Upgrade 41

3 Data Sample Selection and Integrated Luminosity Evaluation 4531 Data Sample Event and Track Selection 4532 Integrated Luminosity Evaluation 46

321 F inorm Calculation 47

322 The MB Trigger Cross Section 50323 Lint Evaluation 51

4 Monte Carlo Simulations 5341 Light-Meson Decays 53

411 Kinematical Distributions 54412 Dalitz Decays 54413 Two-Body Decays 57

42 Dimuons from Open Heavy-Flavor Decays 60421 PYTHIAndash FONLL Comparison 61422 Decay Chain Length in the Open Heavy-Flavor Processes 62

xii Table of contents

5 Signal Extraction 6551 Combinatorial Background Evaluation and Subtraction 65

511 The Event Mixing Technique 66512 Monte Carlo Validation of the Event Mixing Technique 67513 The Combinatorial Background Estimation 68

52 Invariant Mass Fit Procedure 70521 Specific Constraints on the Hadronic Cocktail Components 71522 Correlated Continuum Treatment 72523 A Few Examples of Hadronic Cocktail Fits 76

6 Systematics Evaluation 7961 Systematics on the Signal Extraction 80

611 Relative Branching Ratio of two-body and Dalitz Decays for the ηand ω Mesons 80

612 σηprimeσφ Cross-Section Ratio 80613 σρσω Cross-Section Ratio 81614 Upper limit of the fit 81615 The correlated continuum shape 81616 Systematic Uncertainty Computation 82

62 Systematics from the MC input 8263 Systematics on Trigger Efficiency 83

631 Evaluation of the Trigger Response Function 83632 Results 84

64 Systematics on Tracking Efficiency 85641 Preliminary Check 85642 Tracking Efficiency Evaluation 86643 MC parametrization 88644 Results 89

65 Summary of Systematic Uncertainty 89

7 Light Neutral Meson Production 9171 Estimation of the Number of Generated Mesons 91

711 The Two-Body Decay Case 91712 The Dalitz Decay Case 92

72 Cross-Section Production for Light Neutral Mesons 93721 Double-Differential η Meson Production 93722 ρω Meson Production 94723 Double-Differential φ Meson Production 98

Conclusions 105

A List of Runs 107

B Raw-Background Comparison mdash figures 111

C Hadronic-Cocktail fits mdash figures 123

Table of contents xiii

Bibliography 135

Chapter 1

Physics Motivations

Summary11 Theoretical Baseline 1

111 Quantum ChromoDynamics (QCD) 3112 Chiral Symmetry 6113 Hadronic Matter mdash Quark-Gluon Plasma (QGP) 11

12 Heavy-Ion Physics Experimental Program 12121 Relevant Kinematic Variables 13122 Collision Geometry 14123 Evolution of a Heavy-Ion Collision 15124 Experimental Observables of the QGP 16125 Proton-Proton Collisions 22

13 Low-Mass Dimuon Measurements in ALICE 23

11 Theoretical BaselineThe theoretical framework underlying the subject of the present thesis is the StandardModel of particle physics (SM) The SM gathers the theories describing the electromag-netic weak and strong interactions as well as Higgs sector providing at the same timea classification of all the subatomic particles known in terms of matter constituents andgauge bosons see figure 11 It was developed throughout the latter half of the 20th cen-tury the current formulation having been finalized in the mid-1970s upon experimentalconfirmation of the existence of quarks Since then discoveries of the Wplusmn and Z0 bosons(1983) the top quark (1995) the tau neutrino (2000) and the Higgs boson (2012) havegiven further credence to the Standard Model [1]

Each elementary interaction in the SM is characterized by an interaction range anda set of gauge bosons carrying the interaction charge It should be noted that the SMdescribes the weak and electromagnetic interactions as two different aspects of a singleelectroweak interaction

bull The weak interaction has a very small range of the order of 10minus18 m and is medi-ated by the Z0W+ and Wminus bosons This interaction affects all known elementaryfermions

2 Chapter 1 Physics Motivations

bull The electromagnetic interaction is characterized by an infinite range and affectsany particle having a non-zero electric charge The associated gauge boson is thephoton

bull The strong interaction acts at small distances having a range of the order of 10minus15 mat this range the strong interaction dominates over the other elementary interac-tions The strong interaction is mediated by the exchange of massless gauge bosonscalled gluons that interact with quarks anti-quarks and other gluons via a chargecalled color charge The theoretical framework for the strong interaction is givenby the theory of Quantum Chromodynamics described in more details in the nextsection

12e neutrino

νe

minus1

12

510999 keV

electron

e

RGB23

12

22+06minus04 MeV

up

uRGB

minus13

12

47+05minus04 MeV

down

d

12micro neutrino

νmicro

minus1

12

105658 MeV

muon

micro

RGB23

12

127 plusmn 003 GeV

charm

cRGB

minus13

12

96+8minus4 MeV

strange

s

12τ neutrino

ντ

minus1

12

177686 plusmn 016 MeV

tau

τ

RGB23

12

160+5minus4 GeV

top

tRGB

minus13

12

418+004minus003 GeV

bottom

b

plusmn1

1

80385 plusmn 0015 GeV

Wplusmn1

911876 plusmn 00021 GeV

Z

1photon

γ

color

1gluon

g0

12509 plusmn 024 GeV

Higgs

Hst

rong

inte

ract

ion

elec

trom

agne

ticin

tera

ctio

n

weak

inte

ract

ion

6qu

arks

(+6

anti-

quar

ks)

6le

pton

s(+

6an

ti-le

pton

s)

12 fermions(+12 anti-fermions)

13 bosons

Matter Constituents Gauge BosonsGoldstone

bosons

1st 2nd 3rd generation

1

Figure 11 Standard Model of particle physics and the different families of matter

11 Theoretical Baseline 3

111 Quantum ChromoDynamics (QCD)The Quantum ChromoDynamics (QCD) is the theory describing the hadronic physicsphenomena in the framework of the SM For this reason QCD is needed to correctlydescribe and interpret the observations in experiments involving high-energy hadronicinteractions like ALICE at the LHC

The color charge of the QCD can have three different values (red green and blue) aswell as the corresponding anti-colors This determines a part of the mathematical struc-ture of QCD based on the special unitary group of degree 3 mdash the Lie group SU(Nc=3)cThe complete mathematical structure of QCD is based on the Lorentz group L = SO(1 3)for the space-time transformations (gluons are in the vector representation and quarksin the spinor one) a gauge symmetry SU(Nc = 3)c an approximate light flavor symme-try SU(Nf = 3)f (this symmetry is not relevant even approximately for the remaining3 heavy flavors) The introduction of a three-color charge allowed at the beginning ofthe development of the QCD for the reconciliation of the observation of the spin-3

2 ∆++

baryon composed of three up quarks in the same spin state with the Pauli exclusionprinciple

The QCD Lagrangian LQCD

In the Quantum Field Theory formalism of particle physics any theory can be expressedin terms of a Lagrangian The mathematical expression of the Lagrangian density ofQCD1 is

LQCD =flavorssumf

qc1f (ipartmicroγmicroδc1c2 minusmfδc1c2) qc2

f

+flavorssumf

qc1f gsA

amicrotac1c2γ

microqc2f minus

14G

microνa G

amicroν + LCP

(11)

(Besides the explicit flavor summation each index when repeated twice indicates asummation on this index) In equation (11) micro ν are Minkowski indexes ranging from 0to 3 the qcf spinor represents the quark field of flavor f and color c (the Dirac index ofquark fields and γ-matrices are not written explicitly for convenience) mf is the massof a quark of flavor f gs is linked to the coupling constant of the theory αs = g2

s4π(after quantification and renormalization αs becomes a running coupling constant alsoquantification requires the introduction of ghost fields) the gluon fields Aamicro are Lorentzvectors Gmicroν

a is the gluon strength tensor and the ta matrices (generators of SU(Nc=3)c)are defined after the Gell-Mann matrices ta = λa2

The first term of LQCD

Lfree q =flavorssumf

qc1f (ipartmicroγmicroδc1c2 minusmfδc1c2) qc2

f = q (ipart minus mf ) q (12)

is a free Lagrangian representing the propagation of free quarks m representing thediagonal quark mass matrix

1 By language abuse the QCD Lagrangian density is simply named QCD Lagrangian

4 Chapter 1 Physics Motivations

The second term

Lint =flavorssumf

qc1f gsA

amicrotac1c2γ

microqc2f = gsqAq (13)

encodes the minimal (or Yukawa) coupling describing the interaction of the quark fieldswith the gluons

The third term of LQCD involvesGamicroν the gluon strength tensor which can be expressed

asGamicroν = partmicroA

aν minus partνAamicro + gsf

abcAbmicroAcν (14)

The fabc coefficients are the structure constants of SU(3) The first part of the tensor inequation (14) partmicroAaν minus partνA

amicro describes the gluon kinematics in analogy to the kinematics

description of photons in quantum electrodynamics (QED) The last term gsfabcAbmicroA

cν is

specific to QCD and describes the gluon auto-coupling due to the fact the QCD is anon-Abelian theory

The last term in equation (11) LCP is related to a possible violation of the CP-symmetry (due to a breaking of T symmetry and the conservation of the CPT symmetry)in the QCD sector This term is defined as

LCP = θg2s

32π2 GamicroνG

microνa (15)

where G is the dual of GGamicroν = 1

2εmicroναβGαβa (16)

and εmicroναβ is the antisymmetric Levi-Civita pseudo-tensor The θ parameter which wouldtake a non-zero value in case of CP-violation of LQCD can be experimentally accessed bymeasuring the electric dipole momentum of the neutron Its value compatible with zerois currently not explained by the theory [2 3]

The QCD Running Coupling Constant αs

By using the perturbative-QCD (pQCD) and the renormalization group equation [4] it ispossible to extract a running coupling constant αs depending on the momentum transferQ and on a parameter ΛQCD establishing the scale at which the perturbatively-definedcoupling would diverge At first order of perturbation theory αs can be expressed as

αs(Q2) = 12π

(11Nc minus 2Nf ) ln(

Q2

Λ2QCD

) (17)

where Nc is the number of colors (3) Nf is the number of light flavors respecting mq Q

and ΛQCD asymp 200 MeVFigure 12 shows the excellent agreement between available measurements of αs(Q2)

and the pQCD theoretical prediction beyond first order According to the value of thetransfer momentum Q two regimes of QCD can be defined for values of the transfermomentum Q above Q asymp 1 GeV (of the order of the nucleon mass) implying Q ΛQCD(or for distances well below 1 fm corresponding to the nucleon size) QCD is in the regime ofasymptotic freedom for Q 1 GeV QCD behavior is dominated by the color confinementmechanism

11 Theoretical Baseline 5

Figure 12 Summary of measurements of αs as a function of the momentum transfer Q and thepQCD prediction [4]

Asymptotic Freedom

In the large momentum transfer region Q ΛQCD or at small distance the decreasingof the coupling constant αs reflects the fact that the particles interacting over shortdistances 1 fm (the typical size of the nucleon) can be treated asymptotically as quasi-free particles This allows one to use a perturbative approach in performing calculationsbased on series of αs powers Let us notice that asymptotic freedom does not mean thatquarks are not interacting at all in high-energy collisions (the freedom is only asymptotic)Indeed it has been shown that at RHIC energy a strongly interacting QGP (s-QGP) iscreated

Color Confinement

Figure 13 Sketch of twoquark separation

In the small momentum transfer region or large distancethe coupling constant perturbatively diverges The physicalinterpretation for this phenomenon is the color confinementA schematic explanation of this phenomenon is the followingif it was possible to hold two color charges (for example twoquarks) and pull them part the energy density would con-centrate into a flux tube due to the non-Abelian characteris-tics of QCD (differently to QED) The energy would increasewith the separation until it reaches a threshold above whichpair creation is possible Figure 13 sketches this effect known as string breaking This isthe reason why in vacuum it is not possible to observe directly one isolated quark and allof them are found in composite particles named hadrons the color charge of hadrons iszero (hadrons are ldquocolorlessrdquo or ldquowhiterdquo) as the colored flux tube wraps within the hadronitself and can be observed

6 Chapter 1 Physics Motivations

A simple modelisation of the potential V (r) between two quarks is given by the Cornellpotential [5]

V (r) = minusαsr

+ σr (18)

In equation (18) the first term models the asymptotic freedom with a Coulomb potential(this term is dominating at r rarr 0) and the second term (dominating when r rarr infin) iscalled the string potential with the string tension σ sim (260 MeV2)

Hadrons can be classified as

bull mesons composed of one quark and one anti-quark

bull baryons composed of three quarks

bull exotic states like the recently observed tetra-quark etc

112 Chiral SymmetryThe chiral symmetry is one of the two fundamental symmetries of QCD governing low-energy QCD (low-hadronic masses) and the properties of the transition between the par-tonic and the hadronic phases observed in heavy-ion collisions

The chiral symmetry can be conveniently introduced and discussed considering theway Lorentz transformations act on bosons and fermions To start this discussion let usconsider a massless universe To understand the properties of the Lorentz transformationof any quantum state one can decompose it into its fundamental building blocks calledchiral fermions χR (the right chiral fermion) and χL (the left chiral fermion) PhysicallyχR and χL are spinor fields (spin frac12) and the R and L indices denote the helicities ofthe states In a massless universe the helicity is a good quantum number there is noLorentz transformation that can change the ldquoorientationrdquo of the spin hence for any inertialobservers the measured helicity would be the same Since χR and χL are fundamentalstates when Lorentz transformations are considered one can build any spin state bymixing these building blocks mathematically the Lorentz group can then be describedas a SU(2)RotimesSU(2)L group whose fundamental representations2 are χR and χL

Let us now consider a massive fermion state obviously now two observers with differ-ent speed relative to the fermion will measure different projections of the spin along themomentum of the particle the helicity is no more a good quantum number The chiralfermions χR and χL can now transform into one another this mechanism is called thebreaking of the chiral symmetry As anticipated in the introduction of this section thissymmetry is crucial to understand the low-mass sector of QCD since it is dominated byhadronic states composed of almost massless quarks (namely u d s composing the light

2 To see why the SO(13) Lorentz group L can be described by the combination of two SU(2) groupsone has to remember that L contains three rotations (that gives one SU(2) group) and three boosts (thatcan be seen as rotation involving the time direction and an imaginary angle that gives another SU(2)group) Those two algebras are not independent (eg boost and rotation do not commute) but they canbe decoupled into SU(2)RotimesSU(2)L independent algebras

11 Theoretical Baseline 7

neutral meson studied in this thesis) compared to the typical scale of QCD ΛQCD (seetable 11)

u m = 22+06minus04 MeVc2 c m = 127plusmn 003 GeVc2 t m = 160+5

minus4 GeVc2

d m = 47+05minus04 MeVc2 s m = 96+6

minus4 MeVc2 b m = 418+04minus03 GeVc2

Table 11 Quark masses [4]

In the following we will explain with a very simple quark model some observablephenomena linked to the fundamental QCD chiral symmetry the non observation ofdegeneration in mass between the scalar and pseudo-scalar octet as well as the spontaneouschiral symmetry breaking related to the phase transition observed eg in LHC arounda temperature of 170 MeV

a A Lagrangian for a free massless quark

For one chiral quark χR the free Lagrangian is3

Lfree qR = iχdaggerRpart0χR + iχdaggerRminusrarrσ middotminusrarrpart χR (19)

the form of the Lagrangian being dictated by the usual constraints (Lorentz invariancehermiticity conservation laws) but for one quark flavor the state with opposite helicityalso exists in nature for one quark flavor one can write Lfree q = Lfree qR + Lfree qLThis can be conveniently written

Lfree q = qipartq (110)

where q is a Weyl spinor (4 component spinor)

q =[χRχL

] (111)

and the usual notation q = qdaggerγ0 (see chapter 32 of [1])

b Explicit breaking of the chiral symmetry in presence of a mass term

The Lagrangian of a free quark of mass m is

Lfree q = q (ipart minusm) q = L0 + Lm (112)

This Lagrangian contains a mass term which is explicitly written as

Lm = mqq = m(χdaggerRχL + χdaggerLχR

) (113)

The number of R (L) quarks in this system is given by

NRL = χdaggerRχR(χdaggerLχL

) (114)

3 We do not consider Majorana fermions in this manuscript

8 Chapter 1 Physics Motivations

Let us define a transformation belonging to the symmetry group U(1)RotimesU(1)L

χR rarr eiθR χR

χL rarr eiθL χL

Lfree q rarr L0 +m(ei(θLminusθR) χdaggerRχL + ei(θRminusθL) χdaggerLχR

) (115)

this symmetry is broken by the mass term as discuss previously when considering thecase of the boost of a massive fermion the number of R or L quarks is not the samefor all observers However this symmetry restricted to the case of θR = θL equiv θV is notbroken and is associated to the conservation of the fermion number This result in theUV (1) symmetry

q rarr eiθV q lArrrArr[χRχL

]rarr eiθV

[χRχL

] Lfree q rarr Lfree q (116)

The V stands for Vector (it is the conservation of the so-called vector current V micro = qγmicroq)For further convenience we also define UA(1) as the symmetry group with transformationgiven by θR = minusθL equiv θA the A stands for Axial (a transformation in UA(1) is thus givenby q rarr eiθAγ5 q)

c For more than one flavor

Finally let us consider the Lagrangian of a system composed by the two lightest flavorsu and d giving Nf = 2 (but this discussion could also be extended to a system includinga third flavor s light enough compared to ΛQCD)

Lfree light q = iqupartmicroγmicroqu + iqdpartmicroγ

microqd minusmuququ minusmdqdqd (117)

In this case one can introduce for convenience the iso-spinor ψ =(quqd

)

Lfree light q = ψ (ipart minus m0)ψ (118)

= iψpartmicroγmicroψ minus mu +md

2 ψψ minus mu minusmd

2 ψτ3ψ (119)

where m0 is the quark masses matrix τ3 is the iso-spin Pauli matrix (noted τ not toconfuse it with σ3 that acts on spinor index) For convenience let us also use

ψR equiv[quRqdR

]equiv

quR0qdR0

equiv PRψ (120)

wherePR = 1 + γ5

2 (121)

and the same for ψL wherePL = 1minus γ5

2 (122)

11 Theoretical Baseline 9

The symmetry we discussed in paragraph b is extended by adding a mixing ofthe flavor states This is what is usually called in the literature ldquochiral symmetryrdquoSUR(Nf )timesSUL(Nf )

The iso-spinor ψ = ψR + ψL transforms under the chiral symmetry as

ψ rarr eiminusrarrθR middotminusrarrt ψR + ei

minusrarrθL middotminusrarrt ψL (123)

where minusrarrt = ~τ

2 and minusrarrθRminusrarrθL isin (R3)2

As in the one flavor case the kinetic term

Lk = iψLpartmicroγmicroψL + iψRpartmicroγ

microψR (124)

is chiral invariant while the mass term is not However when the mass difference is zero(the so-called exact isospin limit) the SUV (Nf ) symmetry is exact

d The symmetry of the quark sector of QCD mdash the eightfold way

Let us consider only massless quarks (a good approximation for u d and s) giving Nf = 3and the light sector only

LQCD = Lfree light q + Lr (125)

where Lr incorporates the terms appearing in the second line of equation (11) as wellas any term relative to heavy quark Lr transforms trivially or in the same way as aLfree light q For this reason the chiral transformation of LQCD can be studied consideringLfree q only In this massless scenario the largest symmetry group for LQCD can be ex-pressed as G=UR(1)otimesUL(1)otimesSUR(Nf )otimesSUL(Nf ) = UR(Nf )otimesUL(Nf ) A transformationof this group is given by

ψ rarr eiθR t ψR + eiθL t ψL (126)

where t =(1~t

)and θ =

(θ ~θ

) This symmetry would allow one to classify light hadronic

states into double U(Nf = 3) multiplets (one for left-handed and one for right-handed)where scalar and pseudo-scalar members would be invariant under U(Nf = 3) rotationin the flavor space which implies the same mass This is not what is observed Atmost one sees multiplets (approximately) invariant under vector symmetry SUV (Nf = 3)rotation (see paragraph b ) for example the octet of pseudo-scalar mesons π K η andthe decuplet of baryons n p Λ etc

The chiral partner of the cited pseudoscalar meson octet is the scalar octet of the a0κ and σ meson the fact that no degeneracy in mass is observed between the members ofthe pseudoscalar octet and the members of the scalar one is linked to the G symmetrybreaking For convenience one can rewrite G = UR(Nf = 3)timesUL(Nf = 3) as

G = UV (1)otimes UA(1)otimes SUV (3)otimes SUA(3) (127)

where

bull UV (1) is the symmetry already discussed in paragraph b it is the conservation ofthe individual flavor quark number

10 Chapter 1 Physics Motivations

bull UA(1) was also introduced in paragraph b This group should be a symmetry in themassless scenario leading to the observation of mη = mηprime (one should see a nonetinstead of an octet of degenerated pseudoscalar mesons) [6] This is howevernot the case The more generally accepted explanation is that the gluon part Lr

of LQCD generates an explicit breaking of the UA(1) symmetry due to non-zeroquantum fluctuations in the gluon strength tensor sim 〈G2〉

G2 = GmicroνGmicroν (128)

bull SUV (3) this is the observed (approximate) symmetry between the masses of themembers of a multiplet4 This means that the SUV (3) symmetry is good enough toclassify hadronic states this corresponds to ldquothe eightfold wayrdquo

bull SUA(3) this group should be again a symmetry in a massless scenario one wouldthen observe a degeneracy between the scalar and the pseudoscalar meson octetThis is not the case because the chiral symmetry SUV (Nf )otimesSUA(Nf ) is sponta-neously broken (Goldstone mechanism) to SUV (Nf = 3) The π K η are the(almost) massless Goldstone bosons of this mechanism

e Spontaneous breaking of the chiral symmetry and phase transition

The Goldstone mechanism just mentioned when discussing the SUA(3) group can beunderstood in the framework of a quark model the Nambu-Jona-Lasinio model [78] withmassless quarks For two light flavors one has

LNJL = ψ (ipart)ψ +Gs

[(ψψ

)2+(ψiγ5~τψ

)2] (129)

where Gs is a coupling constant for four-quark contact interactions It mimics the shortrange strong interaction as a contact interaction This Lagrangian is chirally invariantsince the interaction term is built from a scalar ψψ and its pseudoscalar counterpart soas to be invariant

If the interaction term is sufficiently large (GsΛQCD2 sim 1) quarks can condense

(〈ψψ〉 6= 0) and equation (129) can be rewritten as

LNJL ψ(ipart + 2Gs〈ψψ〉

)ψ + middot middot middot (130)

The quantity mD equiv minus2Gs〈ψψ〉 acts exactly as a mass term (it is the so-called dynamicalmass) and spontaneously breaks the chiral symmetry

If temperature increases generally there will be a screening of the interaction and〈ψψ〉(T ) = 0 for T gt Tc where Tc is called the phase transition temperature the chiralsymmetry is said to be restored At approximately the same temperature the decon-finement occurs hence the high temperature phase is also known as the Quark GluonPlasma (or QGP) phase The fact that chiral symmetry restoration and deconfinementare occurring at almost the same temperature happens because in low-energy QCD thereis basically one scale only ΛQCD

4 The observed mass differences are not exactly zero because the u d s mass differences are notexactly zero (isospin limit)

11 Theoretical Baseline 11

minusrarrπσ

Ueff

A

B

a

minusrarrπσ

Ueff

b

minusrarrπσ

Ueff

c

1Figure 14 Effective potential as a function of ~πndashσ left to right going towards fully chirality restora-tion

If one takes σ sim ψψ and ~π sim ψiγ5~τψ the chiral symmetry restoration can be describedin the same way as the Goldstone mechanism related to the Higgs mechanism At lowtemperature one has a Goldstone effective potential Ueff (see figure 14 a) that has the well-known Mexican hat shape the ldquovacuumrdquo (relative to the expectation value 〈~π〉 = 0 = 〈σ〉)is in fact unstable The physical vacuum is located at the bottom of the potential on theso-called chiral circle As the temperature increases the chiral circle shrinks until the state〈~π〉 = 0 = 〈σ〉 is stable (see figure 14 c) this is the restoration of the chiral symmetry

The chiral symmetry restoration has an impact on the in-medium spectral functionsof hadrons the most easily accessible experimental observable related to this mechanismis the ρ meson thanks to its short life-time (13 fmc) allowing it to be produced anddecay inside the volume of the QGP typically obtainable in heavy-ion collisions

113 Hadronic Matter mdash Quark-Gluon Plasma (QGP)

As already remarked low-energy QCD mechanisms are driven by the same scale param-eter ΛQCD this is the reason why chiral symmetry restoration and color deconfinementhappen under the same thermodynamical conditions identifiable in the QCD phase dia-gram shown in figure 15

This schematic diagram presents two main regions The first one is the region atlow temperature and density where quarks and gluons are confined inside hadrons andthe chiral symmetry is broken The second region is characterized by large values oftemperature and or net baryon density where the relevant degrees of freedom are quarkand gluon and is a new state of matter the Quark Gluon Plasma (QGP) These tworegions are separated by a phase transition At vanishing net baryonic density (from 0 toan hypothetical critical point) this frontier is a smooth phase (ldquocross-overrdquo) transitionAt increasing value of net baryonic density beyond an hypothetical critical point thefrontier becomes a first order phase transition At extreme values of the net baryonicdensity and low temperature other hadron phases of the hadronic matter can be possibleas the hypothetic color superconducting phase proposed by some theoretical speculations

The only way to get experimental access to the QCD phase diagram in the regionof deconfinement under controlled conditions is to perform ultra-relativistic heavy-ioncollisions Different regions of the phase diagram can be covered by changing the center-

12 Chapter 1 Physics Motivations

Figure 15 Schematic QCD phase diagram as a function of temperature and net baryon density

of-mass energy of the collision as the energy increases the initial temperature of thesystem increases and its net baryonic density decreases At the high-energy frontier theexperiments carried at the Large Hadron Collider (LHC) at CERN and the RelativisticHeavy-Ion Collider (RHIC) at the BNL are suited to reproduce the conditions of hightemperature and low-net baryonic density present in the early Universe

In this QCD phase diagram there is a hypothetical Critical Point and this pointprovides a major research focus both theoretically and experimentally On the theory sidelattice QCD (LQCD) gives accurate results only at zero density It can be extrapolatedat finite density Another technique is the use of effective models as the NJL one [7] Onthe experimental side studies of heavy-ion collisions are done with several energies andion species (NA61 STAR PHENIX) and they probe different density regimes Finallycompact star observation may also give results about the zero temperature high densityphase of QCD

12 Heavy-Ion Physics Experimental ProgramThe experimental study of QGP needs this state of matter to be recreated in laboratoryAs we have seen in the previous section high density andor temperature are needed inorder to reach the conditions for the creation of the QGP state these conditions are metin ultra-relativistic heavy-ion collisions This experimental tool allows one to change theenergy density of the system by varying the size and the energy of the colliding nuclei

12 Heavy-Ion Physics Experimental Program 13

Several probes of the QGP exist which will be described later in this chapter the design ofa heavy-ion detector directly depends on the probes chosen for the experimental program

The relativistic heavy-ion experimental program started in the early 1980s at the BNLAGS [9] and CERN SPS [10] (collision energy per nucleon pair up to radicsNN asymp 20 GeV)and continues today both at the SPS and at the RHIC [11] and LHC [12] colliders whereenergies up to radicsNN = 02 TeV and 5 TeV are reached respectively

121 Relevant Kinematic Variables

Before discussing collision geometry and QGP probes we briefly introduced the mainkinematic variables of interest for heavy-ion physics and particularly for the study pre-sented in this manuscript

Transverse Momentum (pT) The kinematics of a particle can be described by anenergy-momentum quadrivector In the context of a high-energy experiment where aprivileged axis is defined by the beams the 3-momentum can be conveniently decomposedinto its longitudinal (pz) and transverse (pT) components The transverse momentum isinteresting for two reasons firstly the transverse degree of freedom is created during thecollision since the initial state is characterized only by the longitudinal degree of freedomof the colliding particles secondly the transverse momentum is invariant under Lorentzboosts along the z-axis allowing one to directly compare the pT distributions measuredin fixed-target and collider experiments

Rapidity (y) The longitudinal degree of freedom of a particle kinematics can be con-veniently expressed in terms of the rapidity variable y defined as

y = 12 ln

(E + pzcE minus pzc

) (131)

It can be shown that the rapidity is additive under Lorentz boosts along the z-axisthis allows one to directly compare the shape of the rapidity distributions measured infixed-target and collider experiments

Pseudo-Rapidity (η) In the ultra-relativistic regime where p m and E asymp p therapidity can be approximated by the pseudo-rapidity η

y = 12 ln

(E + cp cos θE minus cp cos θ

)asymp 1

2 ln(

1 + cos θ1minus cos θ

)= minus ln

[tan

(θ

2

)]equiv η (132)

The pseudo-rapidity is especially useful whenever the energy and the longitudinal mo-mentum pz are not available at the same time in this case the pseudo-rapidity providesan approximation of the rapidity based on the measurement of the polar angle θ only (theangle between the z-axis and the particle direction)

14 Chapter 1 Physics Motivations

Invariant Mass In case the particle of interest for a given analysis is not directlyobservable (because of its short life time) its kinematics can still be reconstructed byidentifying and measuring its decay products the quadrivectors of the daughters canbe composed to obtain the quadrivector of the mother particle from which can be easilyobtained its invariant massm2c4 = E2minusp2c2 In the specific case of the analysis presentedin this thesis the φ meson (as well as the other low-mass neutral mesons η ρ ω) hasbeen identified through its decay into two muons

122 Collision GeometryTo clearly interpret the observables in a heavy-ion collision one also needs to characterizeits geometry The two main geometric parameters characterizing a heavy-ion collision arethe centrality and the event plane

Centrality mdash The centrality is a concept related to the finite size of the collidingnuclei in fact heavy nuclei (like the lead nuclei accelerated at the LHC) can be regardedas extended objects consisting of several nucleons Some of these nucleons participate tothe collision and are called participants while the remnants do not interact and are calledspectators see figure 16-left

x

y

ΦRP

Figure 16 Schematic representation of a lead-lead collision

As it can be also seen in figure 16-left an impact parameter b can be identified whenlooking at a nucleus-nucleus collision in the transverse plane If this parameter is nullthe overlap between the two nuclei and the energy available in the overlapping volumeis maximal these collisions are classified as most central For larger impact parametersthe overlap region between the two nuclei and the energy available in the overlappingvolume become smaller these collisions are classified as semi-central semi-peripheral andperipheral for increasing values of b If the impact parameter is larger then two nuclearradii the collision is called ultra-peripheral and there is no hadronic interaction betweenthe two nuclei

The impact parameter in a heavy-ion collision is not directly measurable due to itsfemtoscopic size Yet b (so the centrality of the collision) can be estimated by quantifyingthe produced particle multiplicity since the two quantities are strongly correlated [13]An effective way to establish this correlation is provided by the Glauber Model [14]

In smaller collision systems like pp and p-Pb the measurement of the produced parti-cle multiplicity is still possible giving insight into the energy of the partonic interactions

12 Heavy-Ion Physics Experimental Program 15

involved in the collision (the so-called ldquoevent activityrdquo) However due to the loose corre-lation between this quantity and the geometry of the collision in such small systems [13]no geometrical interpretation can be established in this case

Event plane mdash In case the collision is not head-on it is possible to define the eventplane as a plane formed by the beam direction and the impact parameter The transverseprofile of this plane in non-central nucleus-nucleus collisions is represented in the rightpanel of figure 16 The determination of the event plane orientation event-by-event isimportant to characterize the azimuthal anisotropies observed in the measurement of theparticles produced in the collisions

123 Evolution of a Heavy-Ion CollisionFigure 17 illustrates the evolution of the hadronic collision in the two cases where theQGP is created (right side) or not (left side)

Figure 17 Space time evolution left-side without QGP right-side with QGP

Collisions with creation of QGP mdash In this case a dense and hot system of freepartons is created in the collision the typical size of the system is such that a ther-modynamical approach can be adopted and a medium temperature defined This sys-tem of deconfined quarks and gluons undergoes multiple interactions and the expansioncharacterized by a hydrodynamic-like collective expansion During this expansion thehadronization starts and there is a cooling of the system until the critical temperatureof the transition between the partonic and hadronic phases (Tc) is reached The coolingcontinues the medium is a hadronic gas until the temperature of chemical freeze-out(Tch) is reached (from above) beyond this point the inelastic interactions stop and the

16 Chapter 1 Physics Motivations

composition of hadronic species is fixed The cooling continues until the kinetic freeze-outis reached beyond this point the elastic interactions also stop and the hadrons fly to thedetectors with kinematic distributions characterized by a temperature Th

Collisions without creation of QGP mdash In this case the collision starts by a pre-equilibrium partonic phase which directly leads to the hadronic phase without passingthrough any significant hydrodynamic or thermodynamic evolution After the elasticinteractions between the hadrons stop the species and their kinematics are fixed

124 Experimental Observables of the QGPA variety of observables exists giving insight into the properties of the QGP each ob-servable providing a complementary piece of information

Bulk physics light-flavor radiation

Figure 18 Hadron yields from ALICE at theLHC and fit with the statistical hadronizationmodel [15]

The bulk radiation is mainly composed oflight-flavored hadrons (u d s quarks) Hav-ing a typical scale of 1 fm 1(200 MeV)these hadrons cannot exist inside the decon-fined medium For this reason the light-flavor radiation measured by the detector isformed at the transition between the QGPand the physical vacuum taking place at thecritical temperature Tc 160minus 180 MeVThis fact is confirmed by the good agreementbetween the measured relative abundancesof the main light hadron species (includinglight hypernuclei) and the prediction of a sta-tistical hadronization model with fixed ther-modynamical parameters at the transitionphase see figure 18

The global hydrodynamical flow drivingthe expansion of the deconfined medium in-

duces the radial flow characterizing the light-flavor radiation pT spectrum Experimen-tally it is possible to observe this radial flow by measuring the pT dependence of the yieldfor the various species of the bulk radiation an example is given in figure 19

Moreover if the initial conditions are not spherically symmetric as it is in fact the casein non-central heavy-ion collisions the difference in pressure in different spatial directionswill lead to a further ldquodirectedrdquo or ldquoellipticrdquo flow (characterized by the v2 parametersin the Fourier expansion of the azimuthal particle distribution) Since the elliptic flowdepends on the initial conditions of the expending medium (like the geometry and theshear viscosity) the flow studies of hadron spectra can provide information about theearlier pre-hadronic stages of the collisions For example figure 110 illustrates how the

12 Heavy-Ion Physics Experimental Program 17

Figure 19 Transverse momentum distributionsof the sum of positive and negative particles asmeasured by ALICE fitted individually with ablast wave function compared to RHIC dataand hydrodynamic models [16]

Figure 110 Elliptic flow coefficient of chargedparticle in PbndashPb collisions as a function of cen-trality compared to viscous hydrodynamic re-sults [1718]

shear viscosity (ηs) of the medium can be estimated by the analysis of the centralitydependence of the v2 parameter

Strangeness productionWithin the light-flavor radiation strangeness production plays a peculiar role since thereare no strange valence quarks in the initial state of the collision as opposed to u and dquarks yet they are sufficiently light to be abundantly created in the course of the colli-sions High-pT strangeness production happens either at the early stages of high-energycollisions in hard partonic scattering processes by flavor creation and flavor excitation(see Feynman diagrams in figure 111) or during the subsequent partonic evolution viagluon splittings Low-pT strangeness production is dominated by non-perturbative pro-cesses like string fragmentation however due to the heavier mass of the strange quark(95plusmn 5 MeVc2) than the u and d quarks the production of strange hadrons in fragmen-tation processes is suppressed in comparison to the production of hadrons containing onlyu and d quarks

q

q s

s g

g s

s

g

g s

s g

g s

s

Figure 111 Feynman diagrams in pQCD at first order for the strangeness production inside QGP

18 Chapter 1 Physics Motivations

Figure 112 pT-integrated yield ratios of strange and multi-strange hadrons to (π+ + πminus) as afunction of 〈dNchdη〉 measured in the rapidity interval |y| lt 05 [20]

An enhancement of strange hadron production was historically proposed [19] as anindication of the QGP formation the argument is that strangeness production would beenhanced by the large energy density available in the medium the enhancement scal-ing with the strangeness content of each hadron Figure 112 shows the ratio of strangehadrons over pions as a function of event multiplicity for pp p-Pb and Pb-Pb collisionsIn this figure one can appreciate the difference of the measured enhancement for strangehadrons containing different numbers of strange quarks Ks mesons and Λ baryons con-taining one strange quark Ξ baryons containing two strange quarks and Ω baryonscontaining three strange quarks

JetsIn high-energy collisions a significant production of hard partons is observed thehadronization of these partons produces a narrow cone of hadrons and other particlescorrelated together named jet In heavy-ion collisions jet measurements offer the pos-sibility to probe the deconfined medium by measuring the energy loss of the initial hardparton (jet quenching) and the modification of the jet cone structure and composition(jet broadening) Due to the high energy involved in the production of hard partons jetphysics in heavy-ion collision basically started at RHIC in 2000rsquo whereradicsNN values of theorder of 100 GeV became available for the first time Today jet physics in heavy-ion col-lisions profits from the larger energies available at the LHC implying larger cross-sectionsfor hard scattered partons and an extended range of jet energies

In figure 113 and 114 two examples of jet physics results in heavy-ion collisions are

12 Heavy-Ion Physics Experimental Program 19

Figure 113 The b-tagged jet RAA as a functionof Npart for two jet pT selections in Pb-Pb atradicsNN = 276 TeV in CMS [21]

(GeVc)Tassoc

p1 15 2 25 3 35 4 45

)shyπ

++

π)

(p

(p+

0

02

04

06

08

1

12

1415)plusmn lt η∆06 lt plusmn lt 052 φ∆Bulk Ratio (shy052 lt

lt 04)η∆ lt 052 shy04 lt φ∆Peak shy Bulk Ratio (shy052 lt

Pythia (Peak shy Bulk Ratio)

= 276TeV 0shy10 centralNN

sPbshyPb

lt 100 GeVcTtrig

50 lt p

ALIminusPRELminus15474

Figure 114 Ratio of proton to pion spectraas function of pT for the ldquobulkrdquo and ldquopeak-bulkrdquo [22]

shown In figure 113 the nuclear modification factor (RAA) of b-tagged jets is shown as afunction of Npart as measured by the CMS experiment at the LHC in Pb-Pb collisions atradicsNN = 276 TeV A clear decreasing trend for RAA is observed for increasing values of

Npart interpreted as a manifestation of the jet-quenching mechanism In figure 114 theproton-over-pion ratios in the bulk and in jet are shown as a function of pT measuredby ALICE in Pb-Pb collisions at radicsNN = 276 TeV The comparison of the measuredproton-over-pion ratio in jets (ldquopeak-bulkrdquo) with the prediction from PYTHIA suggeststhat no significant medium-induced modification of particle ratios is at play in jets

Heavy flavorsThe abundant production of c and b quarks at LHC offers a unique possibility to un-derstand the details of the energy loss thermalization and hadronization mechanismscharacterizing the interaction of heavy quarks with the medium

The energy loss can be studied through the measurement of the pT-dependence of thenuclear modification factor RAA for the various heavy flavor hadron species In figures 115and 116 the RAA averaged over the main non-strange D-meson species is compared withthe RAA of light-flavored mesons and (non-prompt) Jψ from B decays respectivelyprobing the suppression hierarchy RB

AA gt RDAA amp Rlight quarks

AA reflecting the different energyloss of light charm and beauty quarks Despite the large uncertainties the data suggesta similar energy loss for the charm and light quark a scenario also supported by sometheoretical models [23] The heavy quark hadronization mechanism in the medium can bestudied by comparing the production of various species of heavy flavor hadrons [2425]

QuarkoniaQuarkonia are resonance states of charm-anticharm (charmonia) or bottom-antibottom(bottomonia) pairs Quarkonium measurements provide information on the properties of

20 Chapter 1 Physics Motivations

Figure 115 Prompt D-meson RAA as a func-tion of pT compared to the pion and charged par-ticles RAA in the 0-10 centrality classes [26]

rangpart

Nlang0 50 100 150 200 250 300 350 400

AA

R

0

02

04

06

08

1

12

14

(empty) filled boxes (un)correlated syst uncertψ() 50shy100 for nonshyprompt J

|lt05y |clt16 GeVT

pD mesons (ALICE) 8lt

= 276 TeVNNsPbshyPb

rangpart

Nlang shifted by +10 in plusmnπ

(CMS)ψ Nonshyprompt J|lt12y |clt30 GeV

Tp 65lt EPJC 77 (2017) 252

50shy80

40shy5030shy40

20shy3010shy20

0shy10

|lt08y |clt16 GeVT

p (ALICE) 8ltplusmnπ

ALIminusPUBminus129313

Figure 116 Comparison of the average D-meson RAA in 8ltpT lt16 GeVc with chargedpions in the same pT range and Jψ from Bdecays in 65ltpT lt30 GeVc [27]

the medium in the early stages of heavy-ion collisions being sensitive to the in-mediumdissociation and recombination mechanisms for the various quarkonium states Quarko-nium dissociation was indeed proposed as a signature of the production of QGP in heavy-ion collisions due to a color-screening effect [28 29] in analogy to the Debye-screeningin electrostatics coupled to a dynamical interaction of the heavy-quark pair with thesurrounding partons [3031]

Figure 117 Dimuon mass spectrum in the Υregion in Pb-Pb collisions at radicsNN = 502 TeVwith CMS experiment [32]

rangpart

Nlang0 50 100 150 200 250 300 350 400

AA

R

0

02

04

06

08

1

12

14-micro+micro rarr ψInclusive J

c lt 8 GeVT

p lt 4 y = 502 TeV 25 lt NN

sPb minusALICE Pb

c lt 8 GeVT

p lt 4 y = 276 TeV 25 lt NN

sPb minusALICE Pb

c gt 0 GeVT

p| lt 22 y = 02 TeV 12 lt |NN

sAu minusPHENIX Au

ALI-DER-112313

Figure 118 The participant number depen-dence of RAA for inclusive Jψ in ALICE in Pb-Pb collisions at radicsNN = 502 and 276 TeVand in PHENIX at forward rapidity in Au-Au atradicsNN = 200 GeV

12 Heavy-Ion Physics Experimental Program 21

The dissociation mechanism resulting in the suppression of the less bound quarkoniumstates is best illustrated in figure 117 showing the dimuon mass spectrum in the Υ regionmeasured by the CMS experiment with the Pb-Pb data at radicsNN = 502 TeV comparedto the expected yield in pp One can observe that the suppression of the Υ(3S) state isstronger than the one of the Υ(2S) with respect to the Υ(1S) due to the different bindingenergy of the two resonance states (sequential melting of quarkonium)

For the charmonium states a statistical recombination mechanism is expected to com-pete with dissociation for sufficiently large values of the cc cross-section expected forinstance in Pb-Pb collisions at the LHC energies The interplay of the suppression andrecombination mechanisms has indeed been proposed to explain the ALICE data for thecentrality dependence of the Jψ RAA in Pb-Pb at radicsNN = 502 and 276 TeV shown infigure 118 together with the PHENIX results in Au-Au collisions at radicsNN = 200 GeVFor 〈Npart〉 gt 120 the ALICE Jψ RAA shows no significant centrality dependence and isalmost a factor of 3 larger than the PHENIX data for the most central points no sizablerecombination mechanism being at play at RHIC energy Further insight on the role ofstatistical recombination in charmonium production at the LHC could come from thecomparison of the Jψ elliptic flow measurements with the theoretical models

Electromagnetic probesElectromagnetic radiation (real photons and dileptons from virtual photons) is emittedfrom a variety of processes prompt photons from initial hard scatterings thermal photonsand medium-modified ρ dileptons from the QGP phase real and dileptons from radiativedecays after hadronization The fact that electromagnetic radiation is emitted during thewhole evolution of the collision represents at the same time an advantage (for instancethe possibility of probing the entire lifetime of the fireball) and a drawback (the variouscomponents being hard to disentangle) Another advantage of electromagnetic radiationis that whenever emitted it is not affected during its propagation by the strong inter-action dominating inside the deconfined medium providing a clean probe of hadronicinteractions

Figure 119 shows the pT spectrum of real photons in Pb-Pb collisions atradicsNN = 276 TeV measured by ALICE for three centrality classes In all centrality

classes no evidence for medium influence is observed at high pT At low pT (gt 2 GeVc)on the contrary an excess of real photons with respect to pQCD real photon productionis observed for mid- and central collisions with a temperature of Teff asymp 300 MeV ex-tracted in central collisions [33] This excess might be related indeed to the productionof thermal photons from the QGP phase

Figure 120 shows the excess in the dimuon mass spectrum with respect tothe expected hadronic sources measured by NA60 in semi-central In-In collisions atradicsNN = 173 GeV compared to various theoretical scenarios This excess is domi-

nated by the medium-modified ρ line shape at low mass (gt 1 GeVc2) and by a thermalcontribution at intermediate mass ( 1 GeVc2) and its study allows one to shed lighton the relevant properties of QGP equation of state [34 35]

22 Chapter 1 Physics Motivations

Figure 119 Direct photon spectra in PbndashPbcollisions atradicsNN = 276 TeV for three central-ity classes compared to model in pp collisions atthe same energy scaled by the number of binarynucleon collisions for each centrality class [33]

Figure 120 Dimuon invariant-mass in semi-central In-In collisions with NA60 [34]

125 Proton-Proton Collisions

Proton-proton collisions present various aspects of interest in the context of heavy-ionphysics namely as a reference for heavy-ion observations test for pQCD calculationsinput for phenomenological non-perturbative models and environment for collectivity insmall systems

As a reference for heavy-ion collisions pp measurements are needed in order hot andcold nuclear matter effects to be properly disentangled respectively in nucleus-nucleusand proton-nucleus collisions This implies two necessities collecting pp reference dataat the same radicsNN energy as more complex collision systems and finding appropriatevariables which could relate pp pA and AA observations A primary example is givenby the nuclear modification factor (RAA) defined as the direct ratio of production cross-sections in AA or pA over the corresponding pp reference scaled by the number of binarycollisions for example to study the charged-particle production [36]

Proton-proton collisions are also an ideal environment for the study of hard and softprocesses in vacuum In the first case (jets Jψ Υ ) one has the possibility to testpQCD calculations in the second case constraints on phenomenological models can bederived in terms of kinematic distributions and production cross-sections [3738]

Finally it is possible to use pp collisions for studying the emergence of collective ef-fects in small systems This study is typically performed analyzing the data in classes ofcharged particle multiplicity the onset of collectivity being driven by the event activityIn this context the observation of collective effects in large-activity pp and p-Pb colli-sions showing striking similarities with those observed in Pb-Pb collisions represents anintriguing challenge for theoretical models [39]

13 Low-Mass Dimuon Measurements in ALICE 23

13 Low-Mass Dimuon Measurements in ALICEThis thesis work is focused on low-mass dimuon measurements in pp collisions atradics = 13 TeV For this reason it is interesting to report here about low-mass dimuon re-

sults and currently ongoing analyses in the other collision systems and energies availableLow-mass dimuon production is studied in ALICE in Pb-Pb collisions atradicsNN = 276 and502 TeV in p-Pb collisions at radicsNN = 502 and 816 TeV as well as in pp collisions atradics = 276 502 7 and 8 TeV Due to the favorable position of its two-body decay in the

low-mass dimuon region with no significant competing sources beyond the smooth cor-related continuum from open heavy flavors the φ-meson has been the privileged subjectof the low-mass dimuon analyses in the first years of LHC operation

Pb-Pb collisionsThe LHC provided Pb-Pb collisions in Run 1 at radicsNN = 276 TeV and in Run 2 atradicsNN = 502 TeVDue to the limited statistics of the Run 1 data the φ-meson study is limited to the

pT range from 20 to 50 GeVc for the dimuons in Pb-Pb collisions at radicsNN = 276 TeVsee figure 121 where the lower limit is imposed by the hardware trigger condition onsingle muons (pT 1 GeVc) and the upper limit is defined by the available statisticsThe analysis of the Run 1 low-mass dimuon data allowed the measurement of the nu-clear modification factor RAA of the φ-meson at forward rapidity in Pb-Pb collisions atradicsNN = 276 TeV shown in figure 122 together with the corresponding ALICE mea-

surement at mid-rapidity and the PHENIX measurement at mid-rapidity in Au-Au andCu-Cu collisions at radicsNN = 200 GeV As can be seen from the comparison of the twoALICE sets of points the RAA does not exhibit any significant dependence on the rapidityregion considered on the contrary the PHENIX points seem systematically higher thanthe ALICE ones although still compatible with the latter within the total uncertaintiesAll the data sets agree on the general decreasing trend of RAA as a function of 〈Npart〉

The larger statistics available from the first Pb-Pb data taking at radicsNN = 502 TeVof Run 2 (2015 a second one being foreseen for 2018) allows the analysis of φ-mesonproduction to be performed up to 7 GeVc starting again from 2 GeVc due to thehardware trigger condition The pT dependence of the φ-meson yield could be studied inseveral centrality classes as shown in figure 123 where the data points are fitted withthe power-law function

dNdpTprop pT[

1 +(pTp0

)2]n (133)

where n and p0 are the free parameters of the fit The centrality dependence of φ-mesonproduction is also studied by looking at the central-to-peripheral ratio RAA as a functionof 〈Npart〉 as shown in figure 124 this dependence suggests a general decreasing trendof RAA as a function of centrality

p-Pb collisionsThe LHC provided in Run 1 p-Pb collisions at radicsNN = 502 TeV and in Run 2 at

24 Chapter 1 Physics Motivations

Figure 121 φ-meson yield as a function of pT inPb-Pb collisions at radicsNN = 276 TeV in threecentrality classes and two rapidity regions [40]

Figure 122 φ-meson RAA as functionof 〈Npart〉 in Pb-Pb collision at radicsNN =276 TeV and Au-Au and Cu-Cu collisions atradicsNN = 200 GeV [40]

)c (GeVT

p

0 1 2 3 4 5 6 7 8

shy1 )c

(G

eV

T

pd

yd

φN

2d

6minus10

5minus10

4minus10

3minus10

2minus10

1minus10

1

10

210

Centr 0shy10 x 8 Centr 10shy20 x 2

Centr 20shy40 Centr 40shy60

Centr 60shy90 Power law

= 502 TeVNN

sPbshyPb

lt 4y25 lt

ALICE Preliminary

ALIminusPRELminus117465

Figure 123 φ yield as a function of pT for fivecentrality classes in Pb-Pb collisions at radicsNN =502 TeV [41]

rang part

N lang

0 50 100 150 200 250 300 350

AA

R

0

05

1

15 = 502 TeV

NNsPbshyPb

shymicro+micro rarr φ

lt 4y25 lt c lt 7 GeV

Tp2 lt

ALICE Preliminary

ALIminusPRELminus131928

Figure 124 φ nuclear modification factor Rcpas a function of Npart in Pb-Pb collisions atradicsNN = 502 TeV [41]

13 Low-Mass Dimuon Measurements in ALICE 25

radicsNN = 816 TeV Because of the different energy of the proton and Pb beams in

p-Pb collisions the nucleon-nucleon center-of-mass moves in the laboratory with a posi-tive rapidity in the direction of the proton beam The directions of the proton and Pbbeam orbits can be inverted during the p-Pb data taking periods allowing the ALICEmuon spectrometer to access a forward rapidity region when the proton beam is directedtowards the muon spectrometer (203 lt y lt 353) and a backward rapidity region whenthe Pb beam is directed towards the muon spectrometer (minus446 lt y lt minus296)

y

shy4 shy2 0 2 4

(b

)y

dφ

σd

0

005

01

015

02data

HIJING

DPMJET

=502 TeVNN

sALICE pshyPb

c lt 7 GeVT

p1 lt

ALI-PUB-94059

Figure 125 φ-meson cross-section as a func-tion of y in p-Pb collisions at radicsNN = 502 TeVand 10 lt pT lt 70 GeVc Predictions fromHIJING and DPMJET are also shown for com-parison

)c (GeVT

p

0 1 2 3 4 5 6 7

)shymicro

+micro

rarr φ

(F

BR

0

05

1

15

data

HIJING

DPMJET

=502 TeVNN

sALICE pshyPb

|lt353y296lt|

ALI-PUB-94063

Figure 126 φ-meson forward-backward cross-section ratio as a function of pT for 296 lt |y| lt353 in p-Pb collisions at radicsNN = 502 TeVPredictions from HIJING and DPMJET are alsoshown for comparison

Figure 125 reports the φ-meson cross-section as a function of y for p-Pb collisions atradicsNN = 502 TeV showing a clear asymmetry between the forward and backward regions

not reproduced by the predictions of HIJING and DPMJET also shown To establish a moredirect comparison of the φ-meson cross-section in the forward and backward regions thecross-section was extracted as a function of pT in the common |y| range 296 lt |y| lt 353in terms of the ratio RFB between the forward and backward cross-section shown infigure 126 The observation of RFB values significantly different than 1 is consistent withthe observation of the asymmetry in the y dependence of the cross-section reported infigure 125 No significant pT dependence of RFB is visible within statistical and systematicuncertainties

p-Pb data have also been taken in 2016 at radicsNN = 816 TeV with a total integratedluminosity larger than the one of the radicsNN = 502 TeV data taking (see table 22) Theanalysis of this data is currently ongoing and is expected to produce the first preliminaryresults in 2018

pp collisionsLow-mass dimuon data in pp collisions are available at several center-of-mass energiesradics = 276 7 and 8 TeV (data taken during the LHC Run 1) 502 and 13 TeV (data

taken during the LHC Run 2)

26 Chapter 1 Physics Motivations

pp results atradics = 276 TeV [13] are used as a reference for Pb-Pb collisions at

the same radicsNN Figure 127 shows the opposite-sign dimuon signal (after combinatorialbackground subtraction) integrated over the available pT and y ranges compared to theresult of the hadronic cocktail fit the good quality of the data-MC comparison leads toa robust extraction of the φ-meson signal Figure 128 shows the φ-meson differentialcross-section as a function of pT compared to the Levy-Tsallis function [42]

1pT

dNdpTprop1 +

radicpT2 +m2

φ minusmφ

nT

minusn (134)

with n and T as free parameters In figure 128 data are also compared to the predictionsby PHOJET and PYTHIA tunes ATLAS-CSC D6T Perugia0 and Perugia11 As one cansee a good agreement is found between predictions and data except for PYTHIA tunesPerugia0 and Perugia11 which underestimate the cross-section measurement

)2c (GeVmicromicroM

0 02 04 06 08 1 12 14

)2

c (

dim

uo

ns p

er

25

Me

V

micromicro

Md

Nd

0

05

1

15

310times

micromicro

rarrρ

0πmicromicrorarrω

micromicro

rarr φ

γmicromicrorarrrsquoηmicromicro rarr bb

γmicro

micro rarr

η

micromicro

rarr ω

micromicro rarr cc

= 276 TeVspp

lt 4y25 lt

c lt 5 GeV T

p1 lt

micromicro

rarr η

ALICE

ALI-PUB-94035

Figure 127 Dimuon opposite-sign mass spec-trum in pp collisions at

radics = 276 TeV af-

ter combinatorial background subtraction pT-and y-integrated data compared to the hadroniccocktail fit [13]

)c (GeVT

p

0 1 2 3 4 5

))c

(m

b(

Ge

V

Tp

dy

dφ

σ2

d

shy310

shy210

shy110

1 = 276 TeVsALICE pp

lt 4y25 lt

Data

PYTHIA ATLASshyCSC

PYTHIA D6T

PYTHIA Perugia0

PYTHIA Perugia11

PHOJET

LevyshyTsallis

ALI-PUB-94047

Figure 128 φ-meson cross-section as a func-tion of pT in pp collisions at

radics = 276 TeV

Predictions from PHOJET and PYTHIA are alsoshown for comparison as well as the result of afit with a Levy-Tsallis function [13]

Low-mass dimuon data taken in 2015 in pp collisions atradics = 502 TeV offer the

possibility to establish a data-based reference for Pb-Pb and p-Pb data at the sameenergy The opposite-sign dimuon signal in pp collisions at

radics = 502 TeV is shown

in figure 129 integrated over the available pT and y ranges compared to the resultof the hadronic cocktail fit the good quality of the data-MC comparison allows for arobust extraction of the φ-meson signal The pT-differential φ-meson cross-section couldbe extracted up to 6 GeVc as shown in figure 130 compared to different theoreticalmodels

Low-mass dimuon data in pp collisions atradics = 7 TeV allowed for the study of the pT-

differential ω and φ cross-sections The hadronic cocktail fit on the isolated opposite-signdimuon signal is shown in figure 131 The identification of the ω and the φ meson signals

13 Low-Mass Dimuon Measurements in ALICE 27

)2c (GeVmicromicroM

0 02 04 06 08 1 12 14

)2

c (

dim

uo

ns p

er

25

Me

V

micromicro

Md

Nd

1000

2000

3000

4000 = 502 TeVspp

lt 4 y25 lt c lt 7 GeV

Tp1 lt

γmicro

microrarr

η

micromicrorarrρ

micromicro

rarrω

0πmicromicrorarrωmicro

microrarr

φ

γmicromicrorarrrsquoη

cc

bb

γmicro

microrarr

η

micromicrorarrρ

micromicro

rarrω

0πmicromicrorarrωmicro

microrarr

φ

γmicromicrorarrrsquoη

cc

bb

ALICE Preliminary

ALIminusPRELminus131989

Figure 129 Dimuon opposite-sign mass spec-trum in pp collisions at

radics = 502 TeV af-

ter combinatorial background subtraction pT-and y-integrated data compared to the hadroniccocktail fit [41]

)c (GeVT

p

0 1 2 3 4 5 6 7 8

))c

(m

b(

Ge

V

Tp

dy

dφ

σ2

d

3minus10

2minus10

1minus10

1 = 502 TeVspp

ATLASshyCSCD6TPerugiashy0

Perugiashy11PhojetMonashshy2013

ALICE Preliminary

lt 4y25 lt

ALIminusPRELminus132725

Figure 130 φ-meson cross-section as a functionof pT in pp collisions at

radics = 502 TeV [41]

resulted in the measurements of the pT differential cross-section shown in figure 132 for theω-meson only calculation based of PHOJET and PYTHIA with ATLAS-CSC and D6T tunesfairly agree with the data while the Perugia0 and Perugia11 PYTHIA tunes underestimatethe cross-section by about a factor of 2 and 25 respectively (the same conclusions standfor φ-meson)

)2M (GeVc

0 02 04 06 08 1 12 14

)2

dN

dM

(p

air

s p

er

25 M

eV

c

0

1000

2000

3000

4000

cc

micro micro

rarr φ

micro micro

rarr ω

micro micro rarr ρ

γ micro

micro rarr

η

micro micro

rarr η

0π micro micro rarr ω

γ micro micro rarrrsquo η

lt 5 GeVct

1 lt p

= 7 TeVsALICE pp

25 lt y lt 4

ALIminusPUBminus26621

Figure 131 Dimuon opposite-sign mass spec-trum for pp collisions at

radics = 7 TeV after com-

binatorial background subtraction pT- and y-integrated sample compared to the result of thehadronic cocktail fit [43]

Figure 132 ω-meson cross-section as a func-tion of pT in pp collisions at

radics = 7 TeV com-

pared to the predictions of various phenomeno-logical models [43]

Finally low-mass dimuon data are also available in pp collisions atradics = 8 TeV This

28 Chapter 1 Physics Motivations

)2c (GeVmicromicroM

0 02 04 06 08 1 12 14

)2

c (

dim

uo

ns p

er

25

Me

V

micromicro

Md

Nd

0

2000

4000

6000

8000

10000

12000 ALICE Preliminary

s = 8 TeVradicpp

25 lt y lt 4

c lt 80 GevT

p15 lt

γmicromicro

rarr

η

γmicromicro rarrrsquo η0πmicromicro rarr ω

bb

micromicro

rarr ω micro

micro rarr φ

micromicro rarr ρcc

ALIminusPRELminus133143

Figure 133 Dimuon opposite-sign mass spec-trum in pp collisions at

radics = 8 TeV after com-

binatorial background subtraction pT- and y-integrated data compared to the hadronic cock-tail fit [41]

)c (GeVT

p

0 1 2 3 4 5 6 7 8

))c

(m

b(

Ge

V

Tp

dy

d φσ

2d

3minus10

2minus10

1minus10

1hEmpty

Entries 0

Mean x 0

Mean y 0

Std Dev x 0

Std Dev y 0

s = 8 TeVradicpp ATLASshyCSCD6TPerugiashy0Perugiashy11

PhojetMonashshy2013

ALICE Preliminary

lt 4 y25 lt

ALIminusPRELminus133207

Figure 134 φ-meson cross-section as a functionof pT in pp collisions at

radics = 8 TeV [41]

offers the possibility to enrich the study of light neutral meson production in pp collisionsas a function of

radics providing at a same time a useful reference for the p-Pb data at

the same radicsNN energy The available statistics larger than the one in pp collisions atradics = 7 TeV allows to extract the low-mass dimuon analysis up to pT = 80 GeVc On

the other side the higher single muon threshold implies that the analysis could only startfrom pT = 15 GeVc The pT- and y-integrated opposite-sign dimuon signal is shown infigure 133 with the associated hadronic cocktail fit Figure 134 shows the extracted φcross-section as a function of pT compared to three predictions of EPOS-LHC and PYTHIA-8with and without multiple parton interactions As one can see the EPOS-LHC predictionoverestimates the φ cross-section while the comparison to the PYTHIA-8 predictions seemsto favor a scenario including multiple parton interactions

Chapter 2

ALICE at the CERN LHC

Summary21 The Large Hadron Collider 29

211 The CERN accelerator complex 29212 The LHC schedule 30213 The Experimental Heavy-Ion Program 32

22 A Large Ion Collider Experiment (ALICE) 33

221 The Central Barrel 34222 The Forward Detectors 36223 The Muon Spectrometer 38224 The ALICE software framework 40225 The ALICE Upgrade 41

21 The Large Hadron ColliderThe Large Hadron Collider (LHC) straddling the FrenchSwiss border in average100 meter underground in a circular tunnel of some 27 km of circumference is as fornow the worldrsquos largest and most powerful particle collider It operates at the TeVenergy scale with nominal energy of 14 TeV (in pp collision) and 55 TeVnucleon pair(in Lead-Lead) foreseen to be achieved in 2018 To carry out this technical challengethe CERN machine engineers developed a new accelerating technique based on supercon-ducting magnets (NbTi) cooled down to a temperature below 2 K which can generatemagnetic fields up to 8 T Four main experiments have been installed within the LHCring namely ATLAS (A Toroidal LHC ApparatuS) CMS (Compact Muon Solenoid)LHCb (LHC-beauty) and ALICE (A Large Ion Collider Experiment) ALICE will bedescribed in more details in section 22

211 The CERN accelerator complexFigure 21 displays the LHC ring and the full complex of accelerators upstream the LHCFollowing a complete trip from the proton source to the final output within the LHCprotons are produced in the LINAC 2 and then injected in the BOOSTER (PSB forProton Synchroton Booster) first accelerator ring This accelerating stage increases the

30 Chapter 2 ALICE at the CERN LHC

Figure 21 The LHC and the CERN accelerator complex [44]

proton energy from 50 MeV to 14 GeV Once protons have reached the top PSB energythey are injected into the Proton Synchroton (PS) where their energy is ramped up to25 GeV and then into the Super Proton Synchrotron (SPS) (7 km in circumference) tothe nominal energy of 450 GeV The latter is the LHC injector and is used in parallel toprovide particle beam to other CERN experiments (for example NA61SHINE)

In the case of the LHC heavy ions runs the lead ions are firstly accelerated in aLINAC 3 then further accelerated in the Low Energy Ion Ring (LEIR) which increasesthe lead energy from 42 MeV to 72 MeVnucleon before injection in the PS The leadions are then accelerated and injected in the SPS and from there to the LHC

212 The LHC schedule

During the first LHC run (Run 1 2009ndash2013) several energies and three collision systems(pp p-Pb Pb-Pb) have been explored In pp collisions five different center-of-massenergies have been considered 09 236 276 7 and 8 TeV p-Pb and Pb-Pb collisionshave been measured at radicsNN = 502 TeV and radicsNN = 276 TeV respectively Run 1was followed by a first Long Shutdown (LS1) mainly dedicated to the upgrade of theaccelerator system mdash resulting in an increase of the collision energy from 7minus 8 TeV to13minus 14 TeV in proton-proton collisions (from 276 TeV to 502 TeV in Pb-Pb collisions)mdash and the completion of the detectors of some of LHC experiment (in the case of ALICEthe electromagnetic calorimeter and the Transition Radiation Detector were updated)Run 2 started in mid-2016 and is planned to last until the end of 2018 with pp collisionsdelivered at 502 and 13 TeV Pb-Pb collisions delivered at radicsNN = 502 TeV and p-Pbcollision delivered at radicsNN = 502 minus 8 TeV LS2 is foreseen to start at the beginningof 2019 ending in late 2020 during LS2 the installation phase of the ALICE upgrade

21 The Large Hadron Collider 31

program will take place During Run 3 pp and Pb-Pb collisions will be delivered atthe nominal LHC energy (14 TeV for pp and radicsNN = 55 TeV for Pb-Pb) and the firstPb-Pb data taking at high-luminosity will take place LS3 will be mainly devoted to theinstallation of the High-Luminosity LHC (HL-LHC) providing unprecedented luminositiesin pp collisions at the designed LHC energy During LS3 the CMS and ATLAS upgradeprograms will be finalize Run 4 will see the beginning of the HL-LHC program in ppcollisions and the continuation of the high-luminosity heavy ion program

Figure 22 LHC schedule for 2015 to 2035 [45]

a Delivered Luminosity Measurement in ALICE

In high energy physics the luminosity is an essential concept expressing the interactionrate normalized to the intensity of the interacting fluxes of particles In the specific caseof a collider with beam pulsing the luminosity is defined by equation (21) where Nb

is the number of particles per bunch nb is the number of bunches per beam frev therevolution frequency γ is the relativistic gamma factor εn the normalized transversebeam emittance βlowast the beam beta function at the interaction point (for more details seechapter 4 of [46]) and F the geometric luminosity reduction factor due to the crossingangle at the interaction point (IP) [47]

L = N2b nbfrevγ

4πεnβlowastF (21)

The luminosity determination in ALICE is based on visible cross section measurementsperformed during van der Meer (vdM) scans [48 49] In standard vdM scans the twobeams are moved across each other in transverse directions x and y The two scans are

32 Chapter 2 ALICE at the CERN LHC

performed separately and the visible cross section is given by the detectors used for thedefinition of the minimum bias triggering conditions typically the V0 and T0 in ALICE

213 The Experimental Heavy-Ion ProgramThe goal of the LHC heavy-ion program is to produce the hottest the largest and thelongest-lived volumes of QGP in laboratory and to provide a precise characterizationof this new state of matter For that nucleus-nucleus collisions (A-A) are delivered atenergies up to radicsNN = 55 TeV Proton-proton and proton-nucleus collisions are also partof the LHC heavy-ion program providing the needed baseline (in terms of vacuum-likecross-sections and cold nuclear matter effects) allowing for a correct interpretation of theobservations in A-A collisions

In addition to the LHC there are other experimental complexes developing specificheavy-ion programs The most important one is the experimental program implementedat the Relativistic Heavy Ion Collider (RHIC) [50] hosted at the Brookhaven NationalLaboratory (BNL) in Long Island (New York US) RHIC is a dedicated heavy-ion facilityand it has a large flexibility in the choice of both the nuclear species accelerated (fromprotons to Uranium) and the center-of-mass energy (in the range radicsNN = 75minus200 GeV)Four detectors are installed at RHIC one of them STAR still operates today whilePHOBOS BRAHMS and PHENIX completed there operations respectively in 2005 2006and 2016 At CERN a fixed-target heavy-ion program complementary to the LHC one isalso running at the SPS with the NA61SHINE experiment [51] currently performing asystematic scan both in beam energy (radicsNN = 45minus 173 GeV) and colliding system size

In addition to the upgrade of some of the existing experiments several new heavy-ionprograms are under discussion or already in preparation [52]

bull The NICA1 facility at JINR [53] will operate in collider mode in the center-of-massenergy range radicsNN = 4 minus 11 GeV and in fixed-target mode in the center-of-massenergy range radicsNN = 19minus 24 GeV

bull The FAIR2 [54] facility at GSI3 will provide fixed-target collisions in the center-of-mass energy range radicsNN = 2minus 29 GeV

bull The AFTER4 project [55] aiming at running a fixed-target heavy-ion program withthe LHC beams at a center-of-mass energy of radicsNN asymp 72 GeV

bull The NA60+ [5657] is a project of fixed-target experiment based at the SPS focusingon dimuon observables at a center-of-mass energy range radicsNN = 63 ndash 173 GeV

1Nuclotron-based Ion Collider fAcility2Facility for Antiproton and Ion Research3Gesellschaft fuumlr Schwerionenforschung mbH4A Fixed Target ExpeRiment at LHC

22 A Large Ion Collider Experiment (ALICE) 33

22 A Large Ion Collider Experiment (ALICE)

Figure 23 Scheme of the ALICE detector

ALICE is an experiment optimized for the study of the physics of strongly interactingmatter at extremely high energy density focusing in particular on the investigation of theQGP state and the characterization of its properties A key design consideration drivingthe developement of the ALICE detector is the possibility to study the most energeticPb-Pb collisions delivered by the LHC This is done by measuring the particles emergingfrom the interaction region it is achieved by ALICE by exploiting a rich variety of sub-detectors see figure 23 based on different technologies described in the following sections[58] Beyond the heavy-ion program ALICE is also interested in collecting data in proton-proton (pp) and proton-Lead (p-Pb) collisions where no large volumes of deconfinedmatter are supposed to be produced to be used as a reference for the Pb-Pb ones

In table 21 and table 22 the ALICE running conditions in the LHC Run 1 and Run 2respectively are summarized

System ECM [TeV] Year Delivered luminosity

pp

09 2009 196 microbminus1

236 2009 087 microbminus1

276 2011 46 nbminus1

2013 129 nbminus1

7 2010 05 pbminus1

2011 49 pbminus1

8 2012 97 pbminus1

p-Pb 502 2012 15 microbminus1

2013 0891 nbminus1 and 140 nbminus1

Pb-Pb 276 2010 9 microbminus1

2011 146 microbminus1

Table 21 Summary of Run 1 ALICE data taking considered for published or ongoing analyses [59]

34 Chapter 2 ALICE at the CERN LHC

System ECM [TeV] Year Delivered luminosity

pp

502 2015 14951 nbminus1

132015 694 pbminus1

2016 1335 pbminus1

2017 192 pbminus1

p-Pb 502 2016816 2016 868 nbminus1 and 124 nbminus1

Pb-Pb 502 2015 280 microbminus1

Table 22 Summary of Run 2 ALICE data taking considered for published or ongoing analyses [59]

221 The Central Barrel

The ALICE central barrel refers to the assembly of detectors installed around the inter-action point inside the L3 magnet These detectors are dedicated to the tracking andidentification of isolated charged particles and photons as well as to the reconstructionof jets

Inner Tracking System (ITS)

The Inner Tracking System (ITS) is the internal tracker of ALICE It is formed by sixcylindrical layers of silicon detector the innermost one having an internal radius of 39 cmlimited by the external radius of the beam pipe The radius of the outermost layer is430 cm The geometric parameters of the ITS are summarized in table 23

sub-system name layer technology r(cm) plusmnz(cm)

SPD 1 Pixel 39 1412 Pixel 76 141

SDD 3 Drift 150 2224 Drift 239 297

SSD 5 Strip 380 4316 Strip 430 489

Table 23 ITS Geometric features

The pseudo-rapidity coverage of the ITS is |η| lt 09 The six layers are grouped intosix groups of two layers each differing by the adopted technology The two innermost lay-ers are composed of silicon pixel detectors (SPD) the central one of silicon drift detectors(SDD) the two outermost are composed of silicon strip detectors (SSD) The ITS allowsthe position of the primary and secondary (from strange and charmed particles) verticesto be determined with a resolution better than 200 microm in rφ and 300 microm in z directionFurthermore it contributes to the particle identification complementing the informationprovided by the TPC especially for the low momentum particles (p lt 200 MeVc)

22 A Large Ion Collider Experiment (ALICE) 35

Time Projection Chamber (TPC)

The Time Projection Chamber (TPC) is the main detector of the central barrel It iscomposed of a 51 m long cylindrical drift volume of 90 m3 developing between an innerradius of 85 cm and an outer radius of 247 cm This volume is filled with NendashCO2 and isdivided into two parts by the central cathode which is kept at minus100 kV The end platesare equipped with multiwire proportional chambers (MWPC) As the ITS the pseudorapidity coverage is |η| lt 09 In addition to tracking the TPC provides charged-particleidentification via measurement of the specific ionization energy loss dEdx Due to theadopted technology and the large size the TPC is the slowest detector of ALICE thuslimiting the interaction rate that can be supported

Transition Radiation Detector (TRD)

The Transition Radiation Detector (TRD) is composed of eighteen super-modules dividedinto thirty modules arranged in six radial layers and five sectors along the beam directionThe TRD has full azimuth coverage and spans the pseudo-rapidity region |η| lt 09This sub-detector provides particle identification for electrons of momentum larger than1 GeVc

Time-Of-Flight (TOF)

The Time Of Flight (TOF) detector allows the particle time-of-flight to be measuredThe TOF coverage is |η| lt 09 in full azimuth It has a modular structure organized intoeighteen sectors in azimuth and five modules along the beam axis The whole detectoris inscribed in a cylindrical volume with an internal radius of 370 cm and an externalone of 399 cm The TOF has an intrinsic time resolution of about 50 ps thanks to thetechnology of Multi-Resistive Plate Chambers (MRPC)

High-Momentum Particle Identification Detector (HMPID)

The ALICE HMPID is based on proximity focusing Ring Imaging Cherenkov (RICH)counters and consists of seven modules mounted in an independent support cradle fixedto the space frame at the radial distance of 490 cm from the interaction point Thepseudo-rapidity acceptance is |η| lt 06 and an azimuthal coverage develops between 1and 59 corresponding to 5 of the central barrel acceptance The HMPID allows oneto extend the particle identification for π and K up to pT asymp 3 GeVc and pT asymp 5 GeVcfor protons

PHOton Spectrometer (PHOS)

The PHOton Spectrometer (PHOS) is a high resolution electromagnetic spectrometercovering the pseudo-rapidity range |η| lt 013 and the azimuth between 220 to 320 andinstalled at the radial distance of 460 cm The detector technology is based on lead-tungstate (PbWO4) crystals The PHOS is used to detect photons in the transversemomentum range between 05 to 10 GeVc including diphotons coming from the decayof the light pseudoscalar neutral mesons

36 Chapter 2 ALICE at the CERN LHC

ElectroMagnetic Calorimeter (EmCal)

The ElectroMagnetic Calorimeter (EMCal) and its extension the Di-jet Calorimeter(DCal) are sampling electromagnetic calorimeters with the pseudo-rapidity coverage|η| lt 07 and azimuth coverage from 80 to 187 (for the EMCal) and 260 to 327 (for theDCal) Specific allowance is made in the DCal acceptance for the space occupied by thePHOS detector The combined information of the EmCal and the DCal allows to studyjets and di-jets providing trigger signals for hard jets photons and electrons

222 The Forward DetectorsIn this section the ALICE sub-detectors covering the forwardbackward acceptance regionare presented These detectors are used to measure global observables especially thecentralityactivity of the collisions and the event plane

Forward Multiplicity Detector (FMD)

The Forward Multiplicity Detector (FMD) is based on the silicon strip technology Itis divided in seven disks perpendicular to the beam pipe located at distances between42 and 225 cm from the interaction point The goal of this sub-detector is to study thecharged particle multiplicity in the pseudo-rapidity ranges minus34 lt η lt minus17 and17 lt η lt 51 complementary to the one of the ITS

T0

The T0 is composed of two arrays of Cherenkov counters circularly arranged around thebeam pipe with a time resolution better than 50 ps The forward and backward parts ofthis sub-detector are located at 375 cm and minus727 cm covering a pseudo-rapidity rangeof 461 lt η lt 492 and minus328 lt η lt minus297 respectively It participates to thetrigger decision and to the estimation of the luminosity

V0

The V0 is composed of two scintillator disks installed around the beam axis on each sideof the interaction point The V0-A (for A-side corresponding to positive values of z) isinstalled at 329 cm from the interaction point it has a diameter of 100 cm and covers thepseudo-rapidity range 28 lt η lt 51 The V0-C (for C-side corresponding to negativevalues of z) is installed at minus90 cm from the interaction point it has a diameter of 74 cmand covers the pseudo-rapidity range minus37 lt η lt minus17

The V0 measures the charged particle multiplicity and by the measurement of thetime-of-flight difference between the A and C scintillators makes possible to identify andreject the beam-gas5 events This technique is illustrated in figure 24 beam-beam andbeam-gas events can be easily discriminated on the basis of the time correlation of thetwo signals reported on the x and y axes

5 A beam-gas event corresponds to an interaction between a beam ion and a nucleus of the residualgas in the beam pipe vacuum

22 A Large Ion Collider Experiment (ALICE) 37

Figure 24 Weighted average time-of-flight of the particles detected in V0-C versus V0-A Thedashed line intersection represents the time of the collisions at the interaction point or the crossingtime of the background tracks at the vertical plane z = 0 [60]

The V0 participates in the minimum-bias trigger decision and in the estimation of theluminosity Furthermore this sub-detector is involved in the centrality measurement inPb-Pb collisions

Photon Multiplicity Detector (PMD)

The Photon Multiplicity Detector (PMD) consists of two identical planes of detectorsmade of gas proportional counters with honeycomb structure and wire readout with Leadconverter in between located at 360 cm from the interaction point in opposite side ofmuon spectrometer The PMD covers the pseudo-rapidity region (23 lt η lt 37) Itmeasures the multiplicity and spatial distribution of photons and estimates the transverseelectromagnetic energy and the reaction plane event-by-event

ALICE Diffractive Detector (AD)

The ALICE Diffractive detector (AD) is a ALICE sub-detector which was installed dur-ing the Long Shutdown 2 (2013-2014) The goal of this sub-detector is to increase thepseudo-rapidity coverage (from 88 to 132 units) and to enhance trigger efficiency forlight particles produced in diffractive events This sub-detector also participates in theestimation of the multiplicity event-by-event It is composed of two double layers of scin-tillator counters one on each side of ALICE sensitive to charged particles with pT downto 20 MeVc In the A-side AD is installed at z = 170 m and covers the pseudo-rapidityrange 49 lt η lt 63 In the C-side the sub-detector is installed at z = minus195 m andcovers the pseudo-rapidity range minus70 lt η lt minus48

38 Chapter 2 ALICE at the CERN LHC

Zero Degree Calorimeter (ZDC)

The Zero Degree Calorimeter (ZDC) is composed of two identical sets of quartz spaghetticalorimeters located on both sides of the ALICE detector in fully horizontal position1125 m from the interaction point Each set of detectors consists of a neutron anda proton calorimeter Each of the neutron calorimeters has dimensions 7x7x100 cm3

while the proton calorimeters have dimensions 228x12x150 cm3 The ZDC detector iscompleted by two small electromagnetic calorimeter (ZEM) placed at 735 m from theinteraction point on one side detecting the energy of particles emitted in the pseudo-rapidity range 48 lt η lt 57 The ZDC is used to estimate the centrality in Lead-Leadcollisions

223 The Muon Spectrometer

Figure 25 The ALICE muon spectrometer layout [61]

The ALICE muon spectrometer (represented in figure 25) is 17 m long Thepseudo-rapidity coverage is minus40 lt η lt minus25 corresponding to the angular range171 lt θ lt 178 The muon spectrometer was designed to study quarkonia (Jψand Υ families) and light vector meson production (η ρω and φ) through their dimuondecays and open charm and beauty production (B and D hadrons) in the single-muonchannel The spectrometer is composed of several elements described in the followingsections

a Front Absorber

The first element of the ALICE muon spectrometer starting from the interaction pointis the front absorber (or hadron absorber) The hadron absorber suppresses all particlesexcept muons coming from the interaction vertex (mainly πplusmn and Kplusmn) It is made of

22 A Large Ion Collider Experiment (ALICE) 39

carbon and concrete (cf figure 26) in order to limit the multiple scattering and theenergy loss of the muons The inner beam shield protects the tracking chambers frombackground originating from particles at small angles It is made of tungsten lead andstainless steel to minimize the background arising from primary particles emitted in thecollision and from their showers produced in the beam pipe and in the shield itself

Figure 26 The ALICE front absorber structure [62]

The absorber is located 90 cm away from the interaction point just after the V0-Cand is 413 cm long

b Dipole Magnet

The dipole magnet provides a maximum magnetic field of 07 T and an integral fieldof 3 T middot m It is a warm magnet (one of the largest warm dipoles in the world) andit is cooled with a demineralized water-cooling system ensuring operating temperaturesbetween 15 to 25 C Its dimensions are 5 m in length 71 m in width and 9 m in heightThe dipole is centered at 994 m from the interaction point and the free gap betweenpoles has a diameter of approximately 3 m The dipole is designed to provide a horizontalmagnetic field perpendicular to the beam axis and its polarity can be reverted Themagnetic field is defined by requirements on the mass resolution for the heavy Υ states

c Tracking Chambers

The tracking system of the muon spectrometer is composed of five stations each sta-tion made of two chambers The distance between two chambers of a same station isbetween 10 and 20 cm The chambers are based on a Multiwire Proportional Cham-ber (MWPC) technology with pad-segmented cathodes [63] The tracking system wasdesigned to achieve the spatial resolution of 100 microm in the bending plane needed for ob-taining an invariant mass resolution of sim 100 MeVc2 at the Υ mass The segmentationof the cathodes allows the spectrometer to operate with maximum hit densities of about5 middot 10minus2 cmminus2 sufficiently large to cope with the observed multiplicity in central Pb-Pbcollisions

40 Chapter 2 ALICE at the CERN LHC

d Iron Wall

The iron wall complements the hadron absorber It is 12 m thick and covers a transversesurface of 56times 56 m2 It is located 15 m away from the interaction point before thetrigger chambers The goal of this element is to suppress all hadrons emerging from thefront absorber The combined action of the iron wall and the front absorber imposesthe muons to have a minimum momentum of sim 4 GeVc in order to reach the triggerchambers

e Trigger Chambers

The ALICE muon spectrometer is equipped with two trigger stations allowing events ofinterest for the muon physics to be selected Each station is composed of two chambersbased on the Resistive Plate Chamber (RPC) technology ensuring the time resolution of2 ns necessary for the identification of the bunch crossing The first station is located at16 m just after the iron wall and the second station at 17 m

Several trigger conditions are hard-coded in the trigger electronics The electronicsprovides the possibility to use two pT thresholds used for different physics and the list oftriggers is

bull MSL at least one muon with pT larger than the low-pT threshold

bull MSH at least one muon with pT larger than the high-pT threshold

bull MLL at least two muons of same charge with pT larger than the low-pT threshold

bull MUL at least two muons of opposite charge with pT larger than the low-pT thresh-old

In addition to these trigger conditions the A-pT trigger condition can also be defined itis the minimum-pT trigger threshold for which a muon is firing the trigger and the valueof this trigger is 05 GeVc

In LHC Run 2 the single-muon high-pT threshold was set to 42 GeVc while thevalue of the single-muon low-pT threshold depended on the data taking periods In thepp data taking during Run 2 two different values have been considered for the single-muonlow-pT threshold 1 GeVc allowing one to access φ meson pT down to sim 15 GeVc and05 GeVc allowing one to access φ meson pT down to almost 0 GeVc

224 The ALICE software frameworkThe ALICE software (AliRoot [64] and AliPhysics [65]) is based on ROOT [66] a soft-ware originally designed at CERN for particle physics data analysis ROOT AliRoot andAliPhysics are written in C++ and are used to handle the online-offline data The soft-ware also manages the Monte-Carlo simulation framework by interfacing several MCgenerators (PYTHIA [67] HIJING [68]) and particle transport codes which simulate thedetector response (GEANT3 [69] GEANT4 [70] and FLUKA [71])

The working flow of the ALICE software is represented in figure 27 where the mainstructures of the online-offline handling are shown The reconstruction steps are the

22 A Large Ion Collider Experiment (ALICE) 41

same for the raw data and MC data At the end of the reconstruction chain the dataare available in the AOD format (Analysis Object Data) From the AOD data furtherdata formats can be derived designed for any specific analysis In the case of the analysisperformed in this thesis the AOD events are reduced to the AliLMREvent format containingthe information of interest for the study of light-neutral meson production decaying intomuons

Simulation Reconstruction

Mon

teCarlo

RealData

Particles

HitsSDigitsSDigits Digits

Clusters

Vertex

Tracks ESD AOD

Trigger

Detector

HLT

DAQ Raw Data

Online Offline

Figure 27 Schema of the reconstruction chain for data and simulation

225 The ALICE UpgradeDuring LHC Run 1 and Run 2 the goal of ALICE is to explore the unprecedented energyregime available in heavy ion collisions see section 124 In the LHC Run 3 and Run 4ALICE we move from the exploration phase to a precision-measurement phase For thisreason ALICE is undertaking a complex upgrade program of its detectors with theinstallation of the upgraded sub-detectors to take place in 2019ndash2020 during the LHCLong Shutdown 2

Physics Motivations

The ALICE upgrade will preserve the specificities of the ALICE physics program withrespect to the other LHC experiments The track reconstruction performance will beimproved in terms of spatial precision and efficiency in particular for low-momentumparticles in order to select more efficiently the decay vertices of heavy-flavor mesons andbaryons The particle identification capabilities of the apparatus will be consolidatedthey represent a crucial tool for the selection of heavy-flavor quarkonium and dileptonsignals at low momentum In the following the main items of the foreseen physics programare shortly reviewed

42 Chapter 2 ALICE at the CERN LHC

bull Heavy Flavors characterization of the parton energy loss study of the transportof heavy quarks in the medium and the hadronization of heavy flavors In ALICE thefocus is placed on the low-momentum region down to zero pT and the reconstructionof heavy-flavor hadrons (mesons and baryons) and the possibility to measure theflavor-dependence in low-momentum jets using light flavor strange and charmedhadrons reconstructed within jets

bull Quarkonia study of the quarkonia dissociation (and possible regeneration) asprobe of the deconfined nature and temperature of the medium In ALICE theemphasis is in the low-momenta region and the possibility to study Jψ ψ(2S) andΥ in central and forward rapidity At forward rapidity in particular the MuonForward Tracker (MFT) will allow the prompt Jψ component to be statisticallyseparated from the displaced production and the ψ(2S) to be observed even inthe most central PbndashPb collisions thanks to a strong reduction of the non-promptbackground

bull Low-Mass Dileptons and Thermal Photons estimation of the initial temper-ature of the medium and investigation of the chiral nature of the phase transitionALICE will access this physics both in the dielectron and dimuon channels down tozero pT

bull Beyond Standard Model specific studies are also undergoing to assess the sen-sitivity of ALICE to the measurement of possible low-mass dark matter bosonsdecaying into electron or muon pairs thanks to the improvement of the discrimina-tion between prompt and non-prompt dileptons

Inner Tracking System (ITS)

The current ALICE Inner Tracking System (ITS) will be totally dismounted at the endof the LHC Run 2 to be replaced by a new detector during Long Shutdown 2 The newITS [72] will be composed of seven cylindrical layers of Monolithic Active Pixel Sensors(MAPS) the innermost one having an internal radius of 224 mm limited by the externalradius of the future beam pipe The internal radius of the outermost layer is 3918 mm

The hit resolution of the detector will be of about 5 microm and the material budget ofthe three innermost layers will be reduced from the present 11 to 03 of the radiationlength per layer these features provide an improvement by a factor about three for thetrack impact parameter resolution in the transverse plane The new ITS would have apseudo-rapidity coverage of |η| lt 122 This upgrade will improve the precision in thesecondary vertex separation (from beauty charm and strange particle decays)

Muon Forward Tracker

The Muon Forward Tracker (MFT) [73] will be a new sub-detector of ALICE made of fivedisks of the same MAPS used in the upgraded ITS The MFT will provide precise track-ing and secondary vertex reconstruction for muon tracks in the pseudo-rapidity regionminus36 lt η lt minus25 within the acceptance of the muon spectrometer

22 A Large Ion Collider Experiment (ALICE) 43

Figure 28 Simulation of low-mass dimuons with and without ALICE upgrade

The measurement of prompt dimuon sources in the low-mass region will strongly ben-efit from the addition of the MFT to the muon spectrometer A significant improvementup to a factor of about 4 is expected for the mass resolution of the narrow resonancesη ω and φ for which resolutions of sim 15 MeVc2 are expected (to be compared withthe current sim 50 MeVc2 resolution at the mass of the φ meson see figure 28) thiswill translate into a significant improvement of the measurements involving these parti-cles allowing at the same time a reliable identification of the underlying thermal dimuoncontinuum and the measurement of the in-medium modified line shape of the short-livedρ meson A precision of about 20 is expected for the observation of these sourcescurrently not feasible due to the very small signal-over-background ratio affecting themeasurement with the present muon spectrometer

TPC

The expected increase of the LHC luminosity after LS2 corresponding to an interactionrate about 50 kHz in PbndashPb implies that TPC operation with a gating grid is no longerpossible This motivates the choice of GEMs for the new readout chambers since theyfeature intrinsic ion blocking capabilities that avoid massive charge accumulation in thedrift volume from back-drifting ions and prevent excessive space-charge distortions Thepresent particle identification (PID) capability via the measurement of the specific ioniza-tion dEdx and the combined momentum resolution of the central barrel tracking systemmust be retained by the TPC upgrade [74] preserving the excellent performance of thecurrent detector

Fast Interaction Trigger (FIT)

The Fast Interaction Trigger (FIT) [75] will be a new sub-detector of ALICE expectedto match and even exceed the functionality and performance (fast event triggering min-imum bias luminosity and charged-particle multiplicity measurements) currently secured

44 Chapter 2 ALICE at the CERN LHC

by three ALICE sub-detectors the T0 the V0 and the FMD detectors The location ofFIT will be similar to that of the current V0 and T0 modules with sensors on both sidesof the Interaction Point (IP) The restrictions imposed by the desired functionality tightspace requirements and the need to minimize the material in the vicinity of the inter-action point have narrowed the choice of detector technologies for FIT to either plasticscintillator- andor Cherenkov radiator

ALICE O2 (ALICE Online-Offline)

After the LHC LS2 the Pb-Pb collision interaction rate will be approximately 50 kHzSince the ALICE physics program will focus on untriggerable signals a continuous read-out will be required in order for all events to be recorded The resulting data throughputfrom the detector has been estimated to be larger than 1 TBs for PbminusPb events roughlytwo orders of magnitude more than in Run 1 and Run 2 To minimize the costs and therequirements of the computing system needed for data processing and storage ALICE isdeveloping a new Computing Framework for Runs 3 and 4 called ALICE Online-Offline(ALICE O2) [76] This framework is designed for a maximal reduction of the data volumeread out from the detector as early as possible during the data-flow

Chapter 3

Data Sample Selection andIntegrated Luminosity Evaluation

Summary31 Data Sample Event and Track Selection 45

32 Integrated Luminosity Evaluation 46

321 F inorm Calculation 47

322 The MB Trigger Cross Section 50

323 Lint Evaluation 51

31 Data Sample Event and Track SelectionThe analysis presented in this thesis is based on a data sample collected by ALICE in2016 in pp collisions at

radics = 13 TeV amounting to asymp 26 times 108 events recorded with

a dimuon trigger This is the largest data sample recorded with the low-pT threshold atsim 05 GeVc as of today (September 2017)

The ALICE data taking is organized into two levels at the first level data are orga-nized into periods each one characterized by the same detector and beam configurationsat the second level data within a given period are further organized into runs each onespanning the interval of two consecutive stops in the data acquisition1 Runs retained forthe analysis are selected on the basis of the quality assurance conditions defined for themuon spectrometer These conditions imply the good operation of all detectors involvedin the analysis of the muon data (muon tracking chambers muon trigger chambers SPDlayers of the ITS V0 and T0) The full list of runs used for the present analysis is reportedin appendix A

The Minimum-Bias (MB) trigger condition for the considered data sample is givenby the logical AND of the signals given by the two V0 detectors (V0AND) [48] Eventscontaining a muon pair are selected by means of a specific dimuon trigger based on thedetection of two muon candidate tracks in the trigger system of the muon spectrometerin coincidence with the MB condition Due to the intrinsic momentum cut imposed bythe detector only muons with pTmicro amp 05 GeVc manage to leave a signal in the triggerchambers Both unlike-sign and like-sign dimuon triggers were collected the like-sign

1 The data acquisition can be stopped either because of beam-related or detector-related issues

46 Chapter 3 Data Sample Selection and Integrated Luminosity Evaluation

trigger sample was downscaled by a factor that varied from run to run according to theinstantaneous luminosity

Background events not coming from beam-beam interactions are rejected by perform-ing an offline selection based on the timing information from the V0 detectors Moreoverit is requested that at least one SPD tracklet contributes to the vertex reconstructed bythe ITS

Track reconstruction in the muon spectrometer is based on a Kalman filter algo-rithm [43 77 78] Muon identification is performed by requiring the candidate track tomatch a track segment in the trigger chambers (trigger tracklet) This request selectsmuons with pTmicro amp 05 GeVc and as a consequence significantly affects the collectedstatistics for dimuons with invariant mass 1 GeVc2 and pT 1 GeVc A harder pro-grammable pT threshold can be imposed on single muons when defining the trigger condi-tions according to the specific physics target it was not the case for the data consideredin the present analysis for which the trigger condition was based on any trigger-matchedmuon Due to the geometrical acceptance of the muon spectrometer the pseudo-rapidityselection minus400 lt ηmicro lt minus250 on the muon tracks is imposed where ηmicro is defined in thelaboratory frame in order to remove the tracks close to the acceptance borders of thespectrometer where the acceptance drops abruptly Muon pairs are built combining twomuon tracks that satisfy the cuts mentioned above

The invariant mass spectrum was obtained both for Opposite-Sign (OS) and Like-Sign (LS) muon pairs the latter being considered for background subtraction relatedpurpose It should be noted that the OS component coming from the LS triggers wassafely neglected in the analysis so that only LS pairs were extracted from the LS-triggeredevents they were upscaled run by run by the inverse of the downscaling factor appliedin the data taking

32 Integrated Luminosity EvaluationThe integrated luminosity for the considered data sample was evaluated as Lint =NMBσMB where NMB is the equivalent number of MB events for the analyzed eventsample and σMB the MB trigger cross section The value of NMB was obtained by usingthe following formula

NMB =sumi=run

F inorm timesN i

MUL (31)

where the N iMUL is the number of events fulfilling the unlike-sign dimuon trigger condi-

tion (MUL given by the presence of at least two tracklets in the muon trigger systemof opposite sign both satisfying the single-muon pT-trigger condition) and F i

norm is thenormalization factor to convert the number of MUL events in the analyzed sample to theequivalent number of MB events In the present analysis two conditions are consideredto estimate the number of MB events

bull The first condition (in the following referred to as ldquoV0rdquo) is theCINT7-B-NOPF-MUFAST one This condition is defined by the coincidence oftwo signals in the V0-A and -C sub-detectors with the requirement that the

32 Integrated Luminosity Evaluation 47

coincidence actually comes from a valid beam-beam interaction (B-NOPF) It is alsorequired that the detectors implied in the definition of the MUL trigger conditionare also included in the readout for the considered M B events this is guaranteedby the composition of the specific MUFAST trigger cluster containing the SPDMUON_TRK MUON_TRG T0 V0 and AD detectors

bull The second condition (in the following referred to as ldquoT0rdquo) is based on the coinci-dence of the above condition CINT7-B-NOPF-MUFAST and the level-0 trigger condition0TVX defined by the coincidence of two signals in the T0-A and -C sub-detectors

321 F inorm Calculation

Three methods are usually considered to compute the Fnorm factor run by run one basedon the counting scaler information (online method) and two based on the reconstructeddata (offline methods)

Pile-Up correction

Regardless of the method one needs to estimate the pile-up contribution in order toproperly correct the estimation of NMB The pile-up correction factor (PU) is defined fora given run i as

PU i = microi

1minus eminusmicroi

microi = minus ln1minus FMBi

purity times L0biMB

Di timesN icolliding times fLHC

where

bull fLHC is the frequency of one bunch in the LHC (11245 Hz)

bull N icolliding is the number of colliding bunches

bull Di is the run duration as given by the Central Trigger Processor (CTP)

bull L0biMB is the scaler input of the level-0 trigger for the considered MB condition

bull FMBipurity is the purity factor associated to the considered MB condition

The purity factor for a generic trigger condition X is computed offline as the fractionof physics-selected (PS) X-trigged events [79] divided by the total number of X-triggedevents

FXipurity = N i

X(PS)N iX(ALL) (32)

In the case of the ldquoT0rdquo MB condition the purity factor is considered equal to 1Figure 31 shows the evolution of the purity factor for all the periods involved in thisanalysis and for the MUL and the ldquoV0rdquo MB trigger conditions

Figure 32 shows the evolution of the pile-up correction factor for the periods involvedin this analysis and for the two conditions considered for the estimate of the number ofMB events

48 Chapter 3 Data Sample Selection and Integrated Luminosity Evaluation

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

0

02

04

06

08

1

Purity factor for MUL

Purity factor for V0 MB condition

B TeyssierWork Thesis

Figure 31 Purity factor for the periods f to p in chronological order

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Pile

-Up

corr

ectio

n fa

ctor

1

105

11

115T0 evaluation

V0 evaluation

B TeyssierWork Thesis

Figure 32 Pile-Up correction for the periods f to p in chronological order

Fnorm Evaluation with Online Method

The online method for the evaluation of the Fnorm factor is based on the information ofthe L0b scaler inputs for the MUL and MB triggers conditions In this case F i

norm iscomputed for a given run i as

F inorm = PU i times FMBi

purity times L0biMB

FMULipurity times L0biMUL

(33)

where FXipurity is the purity factor associated to the events selected by the trigger condition

X This method does exploit the full event sample in the analyzed data The run-by-run

32 Integrated Luminosity Evaluation 49

evolution of the F inorm factor evaluated with this method is given in figure 33 both for

the ldquoV0rdquo and ldquoT0rdquo MB conditions

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Nor

mF

0

2

4

6

310times

method Online V0NormF

method Online T0NormF

B TeyssierWork Thesis

Figure 33 Normalization factor for the periods f to p in chronological order evaluated with theonline method both for the ldquoV0rdquo and ldquoT0rdquo MB conditions

Offline Methods

The offline methods are based on the comparison between the number of minimum biasevents in a given data sample and the number of minimum bias events in the same datasample satisfying at the same time the trigger condition of the analyzed events at thelevel-0 For the first offline method the following formula is used for a given run i

F inorm = PU i times MBi

(MBamp0MUL)i (34)

where

bull MBi is the number of physics-selected MB events

bull (MBamp0MUL)i is the number of physics-selected MB events also fulfilling the MULtrigger condition at the level-0

The run-by-run evolution of the F inorm factor evaluated with this method is given in

figure 34 both for the ldquoV0rdquo and ldquoT0rdquo MB conditionsThe second offline method is based on the formula

F inorm = PU i times MBi

(MBamp0MSL)i timesMSLi

(MSLamp0MUL)i (35)

where

50 Chapter 3 Data Sample Selection and Integrated Luminosity Evaluation

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Nor

mF

0

2

4

6

8

10

12310times

method Offline 1 V0NormF

method Oflline 1 T0NormF

B TeyssierWork Thesis

Figure 34 Normalization factor for the periods f to p in chronological order evaluated with the firstoffline method both for the ldquoV0rdquo and ldquoT0rdquo MB conditions

bull MSLi is the number of physics-selected events satisfying the single-muon triggercondition (MSL given by the presence of at least one tracklet in the muon triggersystem passing the all-pT single-muon threshold) in coincidence with the ldquoV0rdquo MBcondition

bull (MSLamp0MUL)i is the number of physics-selected MSL events (see above) also satis-fying the MUL trigger condition at the level-0

bull (MBamp0MSL)i is the number of physics-selected MB events also satisfying the MSLtrigger condition at the level-0

The run-by-run evolution of the F inorm factor evaluated with this method is given in

figure 35 both for the ldquoV0rdquo and ldquoT0rdquo MB conditionsThe relative rate of the MSL trigger condition relative to the MB and the MUL ones is

larger than the relative rate of the MUL trigger condition to the MB one this guaranteesthis second offline method to profit from a larger event sample resulting in a smallerstatistical uncertainty As expected the results from the two offline methods agree withinthe error bars

322 The MB Trigger Cross SectionThe ldquoMBrdquo cross section σMB was measured with a van der Meer scan for both theldquoV0rdquo and ldquoT0rdquo MB condition and found to be 578plusmn 12 mb for the ldquoV0rdquo conditionand 301plusmn 06 mb for the ldquoT0rdquo condition [80] As reported in [80] ldquowhen the LHC isoperated with isolated-bunch-based filling schemes the two detectors provide indepen-dent measurements of the luminosity with a total uncertainty of 23 When the LHC isoperated with bunch trains the V0-based luminosity is affected by non-trivial systematiceffects in this case the total uncertainty on the luminosity measured with T0 is 34rdquo

32 Integrated Luminosity Evaluation 51

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Nor

mF

0

2

4

6

8

10

12310times

method Offline 2 V0NormF

method Offline 2 T0NormF

B TeyssierWork Thesis

Figure 35 Normalization factor for the periods f to p in chronological order evaluated with thesecond offline method both for the ldquoV0rdquo and ldquoT0rdquo MB conditions

It should be noted that these values refer to the pp data taking of 2015 since thecorresponding results from the van der Meer scan of 2016 (when the data considered inthe present analysis were taken) is not available yet We thus currently assume a 5additional systematic uncertainty on σMB accounting for any possible difference betweenthe efficiency of the detectors involved in the MB trigger conditions between 2015 and2016

323 Lint EvaluationTo obtain the value of Lint for the data taking periods considered in this present analysisone has to assume a reference MB condition and a reference method for the evaluationof Fnorm From equation (31) one can expect that for a given MB condition the valuesof Fnorm coming from the online and offline methods discussed above agree between eachother to give the same estimation of NMB Moreover the definition of the integratedluminosity Lint = NMBσMB implies that the ratio between the NMB(V0) and NMB(T0)and then the ratio between Fnorm(V0) and Fnorm(T0) should be consistent with the ratiobetween σMB(V0) and σMB(T0) As one can see by comparing figures 33 to 35 thethree evaluation methods give compatible estimations for Fnorm However the expectedratio between the ldquoV0rdquo and ldquoT0rdquo estimations of Fnorm is only observed with the onlinemethod For this reason the online method (which also profits from the smaller statisticaluncertainties) is retained for the evaluation of the Lint value to be used for the presentanalysis

The resulting values of Lint are 844plusmn 000(stat)plusmn 042(syst) pbminus1 and904plusmn 000(stat)plusmn 452(syst) pbminus1 respectively when the ldquoT0rdquo and ldquoV0rdquo MBconditions are considered The ldquoT0rdquo MB condition assuring the most stable referenceis finally retained and considered in the present analysis

Chapter 4

Monte Carlo Simulations

Summary41 Light-Meson Decays 53

411 Kinematical Distributions 54412 Dalitz Decays 54413 Two-Body Decays 57

42 Dimuons from Open Heavy-Flavor Decays 60421 PYTHIAndash FONLL Comparison 61422 Decay Chain Length in the Open Heavy-Flavor Processes 62

This thesis work is devoted to the study of light-meson production decaying in two-muon (dimuon) channel The dimuon mass range of interest for this study goes fromthe production threshold (Mmicromicro = 2mmicro) to 15 GeVc2 and is named Low-Mass Region(LMR) This region gives access to the dimuon decays of the light vector (ρ ω and φ)and pseudo-scalar (η and ηprime) mesons discussed in section 41 In addition to these decaysa correlated dimuon continuum is also present in the LMR this contribution is treated insection 42 in terms of open charm and beauty processes

For each process discussed in the following the underlying physics is reviewed andthe main details of the corresponding MC simulations are given All the MC simulationsperformed in this thesis used GEANT3 as transport code

41 Light-Meson DecaysThe properties of the light mesons contributing to the LMR through their dimuon de-cays are reported in table 41 These mesons contribute to the LMR with two types ofdecays the two-body decays and the three-body (Dalitz) decays which will be discussedseparately in the following section All the light-meson decays involved in the LMR aresimulated with the AliGenMUONLMR parametric generator

As can be seen from the quark composition reported in table 41 the ρ and ω mesonscan be used as reference for particle production in the (ud) quark sector while strangenessproduction can be accessed via φ meson (and to a lesser extent η and ηprime mesons)measurement The physical width of the ρ meson significantly larger than one of theother particles contributing to the LMR corresponds to the life time of sim 13 fmc thismakes the ρ an ideal probe of in-medium modifications in the case of QGP productiongiven that a large fraction of the observed ρ mesons would decay inside the hot medium

54 Chapter 4 Monte Carlo Simulations

Particle Pole Mass [MeVc2] Width [MeVc2] Quark Compositionη 547862plusmn 0018 (131plusmn 005) middot 10minus3 1radic

6

(uu + ddminus 2ss

)ρ 77526plusmn 025 1491plusmn 08 1

2

(uuminus dd

)ω 78265plusmn 012 849plusmn 008 1

2

(uu + dd

)ηprime 95778plusmn 006 0198plusmn 0009 1radic

3

(uu + dd + ss

)φ 1019461plusmn 0019 4266plusmn 0031 ss

Table 41 Property of light-mesons involved in the dimuon mass spectrum values taken from [4]

411 Kinematical DistributionsThe kinematics parametrization of the light mesons in the AliGenMUONLMR generator areprovided by a pT-y distribution estimated by PHOJET [81 82] (based on a Dual PartonModel combined with perturbative QCD)

412 Dalitz DecaysAmong the light mesons reported in table 41 the η ω and ηprime mesons give a sizableDalitz decay contribution to the LMR The involved decay channels are summarized intable 42

Process Branching Ratio (BR)ηrarr micro+microminusγ (31plusmn 04) middot 10minus4

ωrarr micro+microminusπ0 (13plusmn 06) middot 10minus4

ηprime rarr micro+microminusγ (108plusmn 027) middot 10minus4

Table 42 Dalitz decay processes in the LMR and the branching ratios used in the analysis

The Feynman diagram corresponding to the Dalitz decay under discussion are shownin figure 41 In the considered processes the parent mesons decay electromagnetically intoone virtual photon with mass M and a third body (real photon or π0) with the virtualphoton converting into a muon pair

η

γlowast

microminus

micro+

γ

1(a) ηrarr micro+microminusγ

ω

γlowast

microminus

micro+

π0

1(b) ωrarr micro+microminusπ0

ηprime

γlowast

microminus

micro+

γ

1(c) ηprime rarr micro+microminusγ

Figure 41 Feynman diagrams of the Dalitz decays of interest for the dimuon LMR

The ALICE muon spectrometer is not equipped for detecting neither the real photonnor the π0 emitted within the Dalitz decays discussed here these decays are identified by

41 Light-Meson Decays 55

]2c [GeV-micro+microM0 01 02 03 04 05 06 07 08

- micro+ micro

MdN

d

0

5

10

15

20

610times (gen)γ-micro+micro rarr η

(a) η

]2c [GeV-micro+microM0 02 04 06 08 1

- micro+ micro

MdN

d

0

2

4

6

610times (gen)0π-micro+micro rarr ω

(b) ω

]2c [GeV-micro+microM0 02 04 06 08 1 12

- micro+ micro

MdN

d

0

1

2

3

4

5610times (gen)γ-micro+micro rarr η

(c) ηprime

Figure 42 Generated dimuon mass distribution of Dalitz decay integrated in full phase space

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

γmicromicrorarrη for -micro+micro)ε times(A

(a) η

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

0πmicromicrorarrω for -micro+micro)ε times(A

(b) ω

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

γmicromicrorarrη for -micro+micro)ε times(A

(c) ηprime

Figure 43 Acceptance times efficiency of Dalitz decay

]2c [GeV-micro+microM0 01 02 03 04 05 06 07 08

- micro+ micro

MdN

d

0

005

01

015

02

610times (rec)γ-micro+micro rarr η

(a) η

]2c [GeV-micro+microM0 02 04 06 08 1

- micro+ micro

MdN

d

0

20

40

60

80

100

310times (rec)0π-micro+micro rarr ω

(b) ω

]2c [GeV-micro+microM0 02 04 06 08 1 12

- micro+ micro

MdN

d

0

20

40

60

80

310times (rec)γ-micro+micro rarr η

(c) ηprime

Figure 44 Reconstructed dimuon mass distribution of Dalitz decay integrated in full phase space

56 Chapter 4 Monte Carlo Simulations

looking at the mass distribution of the dimuons coming from the virtual photon conversionFor this reason it is important to have a theoretical description of the shape of suchmass distributions they can be computed in pure QED under the hypothesis of a point-like electromagnetic transition vertex with the deviation from the real transition vertexquantified by a form factor |F (M2)|2 see Equations (41) to (43)

dΓ (ηrarr micromicroγ)dM = 2M 2

3α

π

Γ (ηrarr γγ)M2

(1minus M2

m2η

)3 (1 +

2m2micro

M2

)

timesradicradicradicradic(1minus 4m2

micro

M2

) ∣∣∣Fη (M2)∣∣∣2

(41)

dΓ (ωrarr micromicroπ0)dM = 2M α

3πΓ (ωrarr γπ0)

M2

(1 +

2m2micro

M2

)radicradicradicradic(1minus 4m2micro

M2

)

times(1 + M2

m2ω minusm2

π0

)2

minus 4m2ωM

2

(m2ω minusm2

π0)2

32 ∣∣∣Fω (M2)∣∣∣2

(42)

dΓ (ηprime rarr micromicroγ)dM = 2M 2

3α

π

Γ (ηprime rarr γγ)M2

(1minus M2

m2ηprime

)3 (1 +

2m2micro

M2

)

timesradicradicradicradic(1minus 4m2

micro

M2

) ∣∣∣Fηprime (M2)∣∣∣2

(43)

where the π0 η ω and ηprime pole masses are taken from the PDG tables [4] and the formfactors are expressed by the pole-parametrization for the η and ω mesons and from aBreit-Wigner form for the ηprime meson∣∣∣Fη (M2

)∣∣∣2 = 1(1minus M2

Λ2η

)2 (44)

∣∣∣Fω (M2)∣∣∣2 = 1(

1minus M2

Λ2ω

)2 (45)

∣∣∣Fηprime (M2)∣∣∣2 = m4

0

(m20 minusM2)2 +m2

0Γ20 (46)

For the η andω form factors the corresponding Λ parameter is taken from a recent analysison p-A NA60 data [83] while for the ηprime form factor the parameters m0 = 0764 GeVc2

and Γ0 = 0102 GeVc2 are extracted from a fit on the Lepton-G data [84] The invariantmass distributions Equations (41) to (43) are implemented in the description of theDalitz decays in the AliGenMUONLMR generator together with the definition of the formfactors Equations (44) to (46) This allows one to extract a properly distributed value ofthe virtual photon invariant mass to be used to simulate the decays ηrarr γlowastγ ωrarr γlowastγ

and ηprime rarr γlowastγ from here the full kinematics of the virtual photon can be extractedallowing in turn the kinematics of the muon pair to be evaluated

41 Light-Meson Decays 57

Figure 42 shows the generated dimuon mass distribution for the three Dalitz decaysof interest here The ηprime mass distribution (figure 42c) shows a characteristic enhancementcorresponding to the ρω peak given by the transition form factor which can be easilyinterpreted in terms of the Vector Meson Dominance model [84] For each decay the pTand y dependence of the product of geometrical acceptance and reconstruction efficiency(A times ε) is shown in figure 43 As expected the phase space coverage at low-pT is moreimportant for the Dalitz decays allowing for larger values of the dimuon invariant massFor the ηrarr micro+microminusγ decay which is the reference process for the extraction of the η-mesonsignal (Atimes ε)micro+microminus is negligible for pT

micromicro 05 GeVc putting a strong constraint in theavailable phase space for the η-meson measurement

Figure 44 shows the reconstructed dimuon mass distribution for each Dalitz decayintegrated over minus400 lt y lt minus250 and 00 lt pT lt 100 GeVc These shapes enter asingredients in the hadronic cocktail fit (discussed in section 52) imposing their profiles tobe sufficiently smooth for each phase space interval considered in the analysis since theseshapes extend over a large mass range and are not easily parameterizable a significantlylarge MC statistics is needed especially when (Atimes ε)micro+microminus is particularly low

413 Two-Body DecaysThe two-body decays of interest for the present thesis work are listed in table 43 withthe corresponding branching ratios For the ω rarr micro+microminus and φ rarr micro+microminus decays thebranching ratios are taken as the average (weighted by the corresponding uncertainty) ofthe available measurements of BR(micro+microminus) and BR(e+eminus) assuming lepton universality inorder to reduce the final uncertainty

Process Branching Ratio (BR)ηrarr micro+microminus (58plusmn 08) middot 10minus6

ρrarr micro+microminus (455plusmn 028) middot 10minus5

aωrarr micro+microminus (728plusmn 014) middot 10minus5

bφrarr micro+microminus (2954plusmn 0030)middot 10minus4

a The value reported in this table for the ω is the weighted average measurement of BR(ωrarr l+lminus)The BR(micro+microminus) is (90plusmn 31) middot 10minus5

b The value reported in this table for the φ is the weighted average measurement of BR(φ rarr l+lminus)The BR(micro+microminus) is (287plusmn 019) middot 10minus4

Table 43 Two-body decay processes in the LMR and the branching ratios used in the analysis

The decay of the vector mesons ρ ω and φ into two muons is mediated by a virtualphoton V rarr γlowast rarr micro+microminus (see figures 45b to 45d) The decay of the pseudo-scalar ηmeson into two muons is a 4th order electromagnetic process (see figure 45a) mediatedby two virtual photons where the micro+ coming from one γlowast and the microminus coming from theother γlowast are contracted

The two-body decays are implemented in the AliGenMUONLMR generator approximatingthe narrow mass line shapes of the η ω and φ mesons with a Dirac delta distributiondefined at the resonance pole mass since their physical widths are negligible with respect

58 Chapter 4 Monte Carlo Simulations

η

γlowast

microminus

γlowast

micro+

1(a) ηrarr micro+microminus

ργlowast

microminus

micro+

1(b) ρrarr micro+microminus

ωγlowast

microminus

micro+

1(c) ωrarr micro+microminus

φγlowast

microminus

micro+

1(d) φrarr micro+microminus

Figure 45 Feynman diagrams of two-body decays of the light neutral meson η ρ ω and φ

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

1

2

3

4

5

610times (gen)-micro+micro rarr ρ

Figure 46 Generated mass distribution for the ρrarr micro+microminus process see equation (47)

to the detector mass resolution On the contrary for the ρ meson due to its natural largemass distribution the following parametrization is used [8385]

dNdM =

α2m4ρ

3 (2π)4

radic1minus 4m2

micro

M2

(1 + 2m2

micro

M2

) (1minus 4m2

π

M2

)32

(m2ρ minusM2

)2+m2

ρΓ2ρ(M)

(2πMT )32 eminusMTρ (47)

with a mass-dependent width

Γρ(M) = Γ0ρmρ

M

M2

4 minusm2micro

m2ρ

4 minusm2micro

32

= Γ0ρmρ

M

(q

q0

)3

(48)

where the Γ0ρ is the full resonance width and mρ the resonance mass pole taken from [4]This distribution is shown in figure 46 one can appreciate the peculiar profile of this lineshape covering practically the whole LMR

For each decay the pT and y dependence of Atimes ε is shown in figure 47 As expectedthe phase space coverage at low-pT becomes larger as the mass of the meson increases

41 Light-Meson Decays 59

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrη for -micro+micro)ε times(A

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrρ for -micro+micro)ε times(A

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrω for -micro+micro)ε times(A

]c [GeVT

p0 2 4 6 8 10

y4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrφ for -micro+micro)ε times(A

Figure 47 Acceptance times efficiency of two body decay

(a) ηrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1

- micro+ micro

MdN

d

0

005

01

015610times (rec)-micro+micro rarr η

(b) ωrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

01

02

03

04

610times (rec)-micro+micro rarr ω

(c) ρrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

002

004

006

008

01

012

610times (rec)-micro+micro rarr ρ

(d) φrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

01

02

03

04

610times (rec)-micro+micro rarr φ

Figure 48 Reconstructed dimuon mass distribution of two body decays integrated in full phasespace

60 Chapter 4 Monte Carlo Simulations

For the ω rarr micro+microminus decay which is the reference process for the extraction of the ω-meson signal (Atimes ε)micro+microminus is significant down to pT = 00 GeVc in the rapidity rangeminus400 lt y lt minus325 and down to pT asymp 20 GeVc towards the y = minus250 limitFor the φ rarr micro+microminus decay from which φ-meson signal can be extracted (Atimes ε)micro+microminus issignificant down to pT = 00 GeVc in the rapidity range minus400 lt y lt minus300 and downto pT asymp 20 GeVc towards the y = minus250 limit

Figure 48 shows the reconstructed dimuon mass distribution for each two-body decayintegrated over minus400 lt y lt minus250 and 00 lt pT lt 100 GeVc These shapes enter to-gether with the Dalitz one discussed in the previous section as ingredients in the hadroniccocktail fit From the mass distributions in figure 48 the detector mass resolution for thenarrow η ω and φ mesons can be estimated performing a Gaussian fit on the centralpart of the peaks the value are found to be ση asymp 458 MeVc2 σω asymp 489 MeVc2 andσφ asymp 520 MeVc2

42 Dimuons from Open Heavy-Flavor DecaysIn the low mass region in addition to the Dalitz and two-body decays of light neutralmesons two other processes may contribute namely the so-called open charm and openbeauty processes In these processes a correlated muon pair comes from the simultaneoussemi-muonic decay of two correlated heavy-flavor hadrons coming from the hadronizationof a heavy qq pair These processes are illustrated in figure 49 for the open charm andbeauty

c

DX

micro

c

D

micro

X

b

BX

micro

b

B

micro

X

Figure 49 Illustration of open heavy-flavor decays

The open charm and beauty processes are generated with the PYTHIA6 MC gener-ator PYTHIA generates the primary cc (or bb) quark pairs performs the correspondinghadronization as well as the decay of the heavy flavor hadrons The decays of the long-livedparticles possibly appearing in the decay chains of the heavy-flavor hadrons are performedby the transport code GEANT3 To save CPU time the PYTHIA6-based parametric gener-ator (AliGenCorrHF) is used developed within the AliRoot framework generating oneheavy-flavor pair per event to further optimize the simulation the first heavy hadronpair is produced in the rapidity hemisphere of the muon spectrometer

The simulation of the open charm and beauty processes depends of the knowledgeof the kinematic distributions of the primary cc (or bb) quark pairs determining the

42 Dimuons from Open Heavy-Flavor Decays 61

kinematics of the first hadron pair and thus the shape of the mass distribution of finalmuon pairs The cc and bb kinematic distributions are known with large uncertainties atforward rapidity at the LHC energies due to the lack of measurements of heavy flavorhadrons in this kinematic range For this reason we also considered a second modelFONLL [86] (for Fixed-Order plus Next-to-Leading Log) giving an alternative descriptionof the cc and bb kinematic distributions based on some perturbative calculation madepossible by the large mass of the charm and beauty quarks To optimize the CPU timefor the simulations based on the FONLL predictions a reweighting is applied on the ex-isting simulations based on the ratio between the (pT minus y) parton distributions given byPYTHIA and FONLL The reweighting has been performed considering three FONLL kinemat-ics distributions the central prediction the prediction corresponding to the upper limitassociated to the uncertainty range and the prediction corresponding to the lower limitassociated to the uncertainty range in this way we can compare up to four hypothesesfor the input of the open charm and beauty processes

The discussion presented in the following section applies to the open charm processas well as to the open beauty one similarly each figure will include two panels the ldquoardquoone dedicated for the open charm case the ldquobrdquo for the beauty case

421 PYTHIAndash FONLL ComparisonTo estimate the difference between the available hypotheses on the input parton kinemat-ics the ratio of the FONLL partonic pT distributions (corresponding to the central valueand the upper-lower limits of the uncertainty range) to the PYTHIA one is shown in Fig-ure 410 In this figure the ratio corresponding to FONLL central value is represented insolid curve and the ratios corresponding to the upper and lower limits of FONLL uncertaintyrange are represented as an uncertainty band As can one see the ratio of the centralFONLL value to PYTHIA deviates significantly from unity the deviation becomes strongerwhen the upper-lower limits of the FONLL prediction are considered The PYTHIA-FONLLdisagreement is stronger for the charm than for the beauty

It is now interesting to investigate how the difference between the PYTHIA and FONLLpredictions for the input kinematic distributions of the cc and bb quark pairs affects theshape of the reconstructed dimuon mass spectra which will be used as ingredients ofthe fit of the data To do so the reconstructed mass spectra corresponding to the fouravailable MC inputs are compared in figure 411 PYTHIA FONLL central value FONLLupper value and FONLL lower value For the sake of comparison the four distributionsare normalized to the same integral In the case of the open charm process figure 411athe differences between the models are clearly visible accross the considered mass rangewhile for the open beauty process figure 411b there is a remarkable agreement betweenthe curves A possible way to quantify the uncertainty on reconstructed dimuon massdistributions of open charm and beauty due to the model assumed for the input partonicdistribution is to evaluate the FONLL over PYTHIA ratios as a function of the dimuon massas shown in figure 412

As expected the ratios for the open beauty process stay significantly closer to unitythan the open charm process By inspecting the graphs one can estimate the uncertaintyon the open charm shape to be of the order of 15 in the LMR significantly increasing

62 Chapter 4 Monte Carlo Simulations

]c [GeVT

p0 2 4 6 8 10

ratio

FO

NLL

Pyh

tia fr

om C

harm

0

1

2

3

(a) charm

]c [GeVT

p0 2 4 6 8 10

ratio

FO

NLL

Pyh

tia fr

om B

eaut

y

0

1

2

3

(b) beauty

Figure 410 Partonic pT distribution ratio FONLL [87] over PYTHIA the black curve represents thereference value of the ratio and the red hatching represents the error according to FONLL model

]2c [GeV-micro+microM0 1 2 3 4 5

au

0

10

20

30

40

50

3minus10times

FONLL

PYTHIA

FONLL - max

FONLL - min

(a) open charm

]2c [GeV-micro+microM0 1 2 3 4 5

au

0

10

20

30

40

3minus10timesFONLL

PYTHIA

FONLL - max

FONLL - min

(b) open beauty

Figure 411 Reconstructed dimuon mass coming from open heavy flavor semi-leptonic decays

towards large masses while from the open beauty shape the uncertainty in the LMR stayswithin 5 We will come back to these uncertainties in section 52 where the fit routineallowing the signal extraction will be discussed

422 Decay Chain Length in the Open Heavy-Flavor Processes

In the open heavy-flavor processes considered in this section the number of decay stepsbetween the initial parton and the final muon (noted decay chain afterwards) can bepotentially large resulting in a weakening of the kinematic correlation between the initialand the final states If the decay chains associated to the two final muons are sufficiently

42 Dimuons from Open Heavy-Flavor Decays 63

]2c [GeV-micro+microM0 1 2 3 4 5

0

02

04

06

08

1

12

14

FONLL over Pythia

FONLL - Min over Pythia

FONLL - Max over Pythia

(a) open charm

]2c [GeV-micro+microM0 1 2 3 4 5

09

095

1

105

FONLL over Pythia

FONLL - Min over Pythia

FONLL - Max over Pythia

(b) open beauty

Figure 412 Dimuon mass spectrum ratio from FONLL (reference min and max value) over PYTHIA

long the initial qq correlation could be substantially washed out in the final muon pairFor this reason it is interesting to study the distribution of the decay chain length (λmicro)in simulated open charm and beauty processes defined as the number of decay stepsbetween the initial parton and the final muon

-microlength 0 2 4 6 8 10

+ microle

ngth

0

2

4

6

8

10

1

10

210

310

410

510

(a) open charm

-microlength 0 2 4 6 8 10

+ microle

ngth

0

2

4

6

8

10

1

10

210

310

410

510

(b) open beauty

Figure 413 micro-chain for open heavy flavor at generated level

In figure 413 the correlation between the λmicro of the positive and negative muons isshown for the dimuons coming from the open charm and beauty simulations In thisfigure on can clearly see that λmicro can get as large as 10 As expected the average λmicrovalues are larger for the open beauty process than the open charm one due to the largerphase space available

Since the λmicro distributions extend over relatively large ranges one can wonder which isthe impact of having short or long muon decay chains on the shape of the dimuon invariant

64 Chapter 4 Monte Carlo Simulations

]2c [GeV-micro+microM0 1 2 3 4 5

au

4minus10

3minus10

2minus10

1minus10

4le plusmnmicroλ = 4 amp plusmnmicroλ 3le plusmnmicroλ = 3 amp plusmnmicroλ 2le plusmnmicroλ = 2 amp plusmnmicroλ 1le plusmnmicroλ = 1 amp plusmnmicroλ

(a) open charm

]2 [GeVc-micro+microM0 1 2 3 4 5

au

4minus10

3minus10

2minus10

1minus10

4le plusmnmicroλ = 4 amp plusmnmicroλ 3le plusmnmicroλ = 3 amp plusmnmicroλ 2le plusmnmicroλ = 2 amp plusmnmicroλ 1le plusmnmicroλ = 1 amp plusmnmicroλ

(b) open beauty

Figure 414 Generated dimuon mass coming from open heavy flavor semi-leptonic decays withparticular λmicro

mass distributions To do so in figure 414 the dimuon mass distributions are shown forfour particular λmicro+λmicrominus combinations As expected shorter decay chains correspond toharder mass distributions

We thus verified that the shape of the invariant mass profile of the open charm andbeauty dimuons depends of the length of the decay chains of the two muons This meansthat to properly reproduce the dimuon mass profile of the open charm and beauty com-ponents in the data we have to correctly reproduce the distribution of the decay lengthchains for the simulated dimuons Now this is not a problem as long as any dimuon froman open charm or beauty process is retained both in the data and in the MC Howeverthe data considered for the signal extraction are obtained by subtracting the combinato-rial background from the raw dimuon spectrum implying that we should retain in theMC the correlated dimuons only But the correlation of a muon pair coming from anopen charm or beauty process is progressively lost as the length of the decay chains of thetwo muons increases and it is extremely hard mdash in terms of analysis strategy and CPUtime mdash to estimate and take such an effect into account in the MC simulations Thisintroduces a source of uncertainty when describing the correlated continuum in the datawith the superposition of the open charm and beauty simulations

Chapter 5

Signal Extraction

Summary51 Combinatorial Background Evaluation and Subtraction 65

511 The Event Mixing Technique 66

512 Monte Carlo Validation of the Event Mixing Technique 67

513 The Combinatorial Background Estimation 68

52 Invariant Mass Fit Procedure 70

521 Specific Constraints on the Hadronic Cocktail Components 71

522 Correlated Continuum Treatment 72

523 A Few Examples of Hadronic Cocktail Fits 76

In this chapter the main source of background for the dimuon decay channel will bediscussed as well as the strategy considered for the extraction of the signals of interestFrom now on following a convention widely used within the ALICE muon communityrapidity values are given in the positive axis justified by the symmetry of the pp collisionsystem with respect to y = 0

51 Combinatorial Background Evaluation and Sub-traction

The present analysis is based on the study of the OS dimuon invariant mass spectrumDimuons are built by combining muon pairs coming from the same event (see section 31)Since dimuons coming from the light-neutral meson decays of interest for this work cannotbe disentangled from the other dimuon sources any pair of muons must be consideredwhen building the dimuon invariant mass spectrum This implies that a fraction of theconsidered dimuons actually comes from randomly paired uncorrelated muons this frac-tion of dimuons is conventionally named ldquocombinatorial backgroundrdquo The ratio betweenthe correlated and uncorrelated dimuon components varies significantly according to thecollision system the considered mass region and the apparatus performance In the low-mass region the ALICE muon spectrometer gives correlated over uncorrelated dimuonratios as large as few units (in pp collisions) and as low as few percents (in the mostcentral Pb-Pb collisions)

66 Chapter 5 Signal Extraction

511 The Event Mixing TechniqueThe combinatorial background for the OS dimuons has been evaluated using an eventmixing technique based on the reasonable assumption that the LS dimuon sample doesnot contain correlated muon pairs The mixing event technique implies the creation of asample of uncorrelated dimuon formed by pairing two muons coming from two differentevents In the following we will identify dimuons built from a same event with the labelldquodirrdquo and dimuons built from different events with the label ldquomixrdquo The event mixingtechnique is illustrated in figure 51

Event A

micro+A1

microminusA2

Event B

microminusB1

microminusB2

micro+B3

Opposite Signmicro+A1micro

minusB1

micro+A1micro

minusB2

microminusA2micro+B3

Like Sign ++micro+A1micro

+B3

Like Sign minusminusmicrominusA2micro

minusB1

microminusA2microminusB2

Figure 51 Illustration of mixing events with two events one with two muons and one with threemuons

The mixed OS dimuon sample is used in the event mixing technique to estimatethe OS combinatorial background in the direct OS dimuon sample for this reason onlyevents sharing same global properties are considered in the event mixing Among theseglobal properties one can cite the z-position of the primary vertex the charged-particlemultiplicity or in nucleus-nucleus collisions the orientation of the event plane In the ppcollisions considered in the present analysis the impact of classifying the events accordingto the z-position of the primary vertex and the charged-particle multiplicity was testedresulting in no difference with respect to the case in which the events are mixed regardlessof their global properties1

The shape of the invariant mass distribution expected for the OS uncorrelated dimuonsis taken for each kinematic range considered in the analysis directly from the outputdistribution Nmix

+minus (M) given by the event mixing technique The normalization is fixed tothe integral of the distribution 2R(M)

radicNdir

++(M) middotNdirminusminus(M) extracted from the data

Nmix+minus (M) minusrarr Nmix

+minus (M)

int2R(M)

radicNdir

++(M) middotNdirminusminus(M) dMint

Nmix+minus (M) dM

(51)

The integral of the 2R(M)radicNdir

++(M) middotNdirminusminus(M) distribution is indeed a good estimation

of the total number of the OS dimuons in the data as long as the LS dimuon samples1 This is valid as long as the analysis is integrated over the mentioned global properties in particular

the charged-particle multiplicity

51 Combinatorial Background Evaluation and Subtraction 67

Ndir++ and Ndir

minusminus do not contain any correlated muon pair The R factor accounts for thepossible differences between the acceptances of ++ minusminus and +minus muon pairs

R(M) = A+minus(M)2radicA++(M) middotAminusminus(M)

(52)

The R factor was estimated as

R(M) = Nmix+minus (M)

2radicNmix

++ (M) middotNmixminusminus (M)

(53)

where Nmix++ and Nmix

minusminus is the number of dimuons for the given sign combination theacceptances are evaluated with the mixing

512 Monte Carlo Validation of the Event Mixing TechniqueA Monte Carlo approach was considered to check the quality of the combinatorial back-ground estimation as follows Events containing two muons were simulated with thekinematics extracted randomly and independently for the two muons from some pT andy distributions taken from the data The azimuthal angle of each muon was randomlydrawn within flat distribution and the charges also randomly attributed In this waythe OS sample of the direct dimuons from this MC event sample could be assumed to bepurely combinatorial by construction We could thus check if the procedure describedabove was able to reproduce its mass shape and normalisation To do this we appliedto this same MC sample the event mixing technique to obtain the mass shape with thecorrect normalization

The ratio RMCdirmix between the true and estimated mass shapes of the combinatorial

OS dimuons was thus extracted for each kinematics interval considered in the analysisSeveral options are possible for the trigger class of the events considered in the eventmixing procedure The considered trigger classes are based on the ldquoV0rdquo trigger conditionsee section 31 to which a specific condition is added based on the response of the muontrigger

bull ldquoMULrdquo based on the presence of at least two tracklets in the muon trigger systemof opposite sign both passing the low-pT single-muon threshold

bull ldquoMLLrdquo based on the presence of at least two tracklets in the muon trigger systemof like sign both passing the low-pT single-muon threshold

bull ldquoMSLrdquo based on the presence of at least one tracklet in the muon trigger systempassing the low-pT single-muon threshold

bull ldquoMSL-onlyrdquo it is defined by this logical combination of trigger conditionsMSL ampMUL ampMLL so it is the condition which minimizes the impact of the dimuontrigger condition on the retained events

The trigger condition of the events considered for the event mixing technique waschosen as the one maximizing the flatness of RMC

dirmix Figures 52 and 53 show that the

68 Chapter 5 Signal Extraction

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeVmicromicroM

0 1 2 3 4 5 6

Dir

ect

Mix

ed

06

08

1

12

14

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

lt 40y25 lt

c lt 100 GeVT

p00 lt = 13 TeVsALICE pp

MUL

MLL

MSL

Figure 52 Comparison of background evalua-tion ratio direct over mixed for ldquoMULrdquo ldquoMLLrdquoand ldquoMSLrdquo conditions

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeVmicromicroM

0 05 1 15 2 25 3

Dir

ect

Mix

ed

09

095

1

105

11

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

MSL

MSL amp MUL amp MLL

Figure 53 Comparison of background evalu-ation ratio direct over mixed for ldquoMSLrdquo andldquoMSL-onlyrdquo conditions

best results are obtained considering events satisfying the ldquoMSL-onlyrdquo condition withldquoMSLrdquo condition also giving a reasonably small deviation of RMC

dirmix from unity On thecontrary the worst performance is associated to the MLL and MUL trigger conditions

The combinatorial background mass shape evaluated for the real data was correctedfor the RMC

dirmix ratio To get rid of the statistical fluctuations due to the limited availableMC sample this ratio is parametrized by the following function before being used tocorrect the data

f(M) = A eminusaM minusB eminusbM +C (54)

where all the parameters are imposed to be positive except C This correction is performedindependently in each (pT y) phase space interval considered in the analysis

513 The Combinatorial Background Estimation

Having validated the method for the evaluation of the combinatorial background it is nowpossible to use it for isolating the dimuon correlated signal in the data Following the resultof the MC validated presented in the previous section the ldquoMSL-onlyrdquo events are used asinput for the event mixing technique The typical mass dependence of the R-factor (ratiobetween the acceptance of LS and OS muon pairs) defined in equation (52) and estimatedas equation (53) is shown in figure 54 for the phase space interval 10 lt pT lt 100 GeVcand minus400 lt y lt minus250 In this same kinematics interval the comparison between theraw dimuon and the combinatorial background is shown in figure 55 The correspondingisolated dimuon correlated signal is shown in figure 56 forMmicromicro lt 100 GeVc2 where thepeaks of the Υ(1S) ψ(2S) and Jψ resonances can be observed and in figure 57 for thelow-mass region where the peaks of the φ and ρω two-body decays are visible togetherwith the structure of the η Dalitz decay

51 Combinatorial Background Evaluation and Subtraction 69

]2c [GeVmicromicroM0 2 4 6 8 10

R

0

02

04

06

08

1

12

lt 1000T

p100 lt

lt - 250y- 400 lt

B TeyssierWork Thesis

Figure 54 The R factor for the data integratedin 10 lt pT lt 100 GeVcand minus400 lt y lt minus250

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 2 4 6 8 10

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

dNd

M

210

310

410

510

610

raw mass spectrum

mass spectrummixOS

B TeyssierWork Thesis

Figure 55 Raw data between 250 lt y lt 400and 10 lt pT lt 100 GeVc

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeVmicromicroM0 2 4 6 8 10

]2 c [d

imuo

ns p

er 2

5 M

eV

micromicrodN

dM

210

310

410

510

610 B TeyssierWork Thesis

Jψ

ψ (2S)

Υ (1S)

Figure 56 Signal after subtraction of combina-torial background in mass range between 02 to100 GeVc2

0 02 04 06 08 1 12 140

01

02

03

04

05

610timesB Teyssier

Work Thesis

ρω

φ

Figure 57 Signal after subtraction of combina-torial background in mass range between 02 to15 GeVc2

70 Chapter 5 Signal Extraction

The combinatorial background estimation and subtraction is particularly challengingat very low pT where the signal-over-background ratio is smaller (as small as asymp 1 at theφ peak) In order to appreciate how the signal can nevertheless be extracted down tovery low pT in figure 58 (top panels) the raw data with the associated combinatorialbackground are shown for 00 lt pT lt 02 GeVc in the rapidity intervals where theacceptance is non-negligible (the most forward region see figures 43 and 47) Thecorresponding isolated signal is shown in the same figure (bottom panels)

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

25310times

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 375 lt y lt 400

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15310times

B TeyssierWork Thesis

(e) 350 lt y lt 375

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310timesB Teyssier

Work Thesis

(f) 375 lt y lt 400

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310timesB Teyssier

Work Thesis

Figure 58 Rapidity evolution of signal and combinatorial background shapes for 00 lt pT lt

02 GeVc

52 Invariant Mass Fit ProcedureAfter subtraction of the uncorrelated background the next step in the analysis is theextraction of the signals of interest from the dimuon correlated invariant mass spectrumin this specific case this means counting how many dimuons from the η rarr micro+microminusγω rarr micro+microminus and φ rarr micro+microminus decays can be extracted from the data for each of the pT-yintervals considered in the analysis For this step the dimuon correlated invariant massspectrum is decomposed into the expected sources composing the hadronic cocktail (two-body and Dalitz decays of light neutral mesons see section 41) via a fit procedure also

52 Invariant Mass Fit Procedure 71

including a description of the correlated continuum component

521 Specific Constraints on the Hadronic Cocktail Compo-nents

In the fit procedure considered in this analysis for the extraction of the signals of interestspecific constraints have been imposed to the components of the hadronic cocktail inorder to reduce the number of degrees of freedom fixing the minor processes (in terms ofreconstructed dimuons) to the major ones Each considered constraint has been also takenas a contribution in the evaluation of the systematics on the signal extraction discussedin section 61

Fixing the relative branching ratios of two-body and Dalitz decays for the ηand ω meson mdash The η and ω mesons contribute to the hadronic cocktail with twodecay channels ηrarr micro+microminusγ and ηrarr micro+microminus for the η and ωrarr micro+microminusπ0 and ωrarr micro+microminus

for the ω Since the branching ratios of each channel is known from the literature thenormalizations of the two-body and Dalitz decay modes can be fixed to each other (as longas the quality of the data does not allow for an independent measurement of the relativebranching ratios) This constraint has been technically implemented for the η meson byconsidering the normalization of the ηrarr micro+microminusγ process has a free parameter and fixingthe ηrarr micro+microminus contribution to it for the ω meson the normalization of the ωrarr micro+microminus

process has been left as a free parameter the contribution of the ω rarr micro+microminusπ0 decaybeing fixed to it For each particle the process associated to the free parameter is the onemore clearly identifiable in the invariant mass profile of the data The relevant branchingratios are listed in tables 42 and 43

Fixing the σηprimeσφ cross-section ratio mdash The contribution of the ηprime Dalitz decayaccounts for a very small fraction of the total reconstructed dimuon mass spectrum forthis reason and because of its continuum shape having no dominant structure apart fromthe broad peak at ρ mass (due to the contribution of the ρ meson to the ηprime form factorsee section 412) the fit procedure is not sensitive to this contribution Consequently thenormalization of the ηprime rarr micro+microminusγ process has been set by fixing the ηprime cross-section tothe cross-section of one of the particles giving a major contribution to the invariant massspectrum namely the φ meson The reference value for the σηprimeσφ cross-section ratio hasbeen evaluated with PHOJET to be 3151 in the rapidity window 25 lt y lt 40 integratedover pT This ratio has been rescaled in each pT-y interval considered in the analysisaccording to the kinematic distributions of the two particles also given by PHOJET

Fixing the σρσω cross-section ratio mdash Due to the broad line shape of the ρ mesonand the limited mass resolution of the detector for the superimposed ω rarr micro+microminus peakthe ρ rarr micro+microminus contribution cannot be easily disentangled in the fit procedure For thisreason the normalization of the ρrarr micro+microminus contribution has been set to the ωrarr micro+microminus

one by fixing the σρσω cross-section ratio The reference value for this ratio has beentaken as 10 from previous measurements [88ndash90]

72 Chapter 5 Signal Extraction

Due to the mass resolution of the ω peak the distinction of the ω and ρ two-bodycontribution is not obvious So it is better to enslave the ρ two-body component to theω to increase the stability of the fit The ratio of the production cross-section of ρω ismeasured to 10 in several previous experiments [88ndash90]

522 Correlated Continuum TreatmentSeveral choices can be considered for the description of the correlated continuum as dis-cussed below As discussed in section 42 the main sources in the correlated dimuoncontinuum are the open charm and beauty processes However as also discussed in sec-tion 42 the evaluation of the MC template of the invariant mass shape of the open charmand beauty dimuons is affected by potentially non-negligible uncertainties according tothe considered input for the cc and bb kinematics and the real degree of correlation of thefinal state muons Moreover one as to consider the possibility of having some residualuncertainty from the combinatorial background subtraction and a possible dimuon com-ponent from correlated light-flavor hadron decays On the basis of these considerationstwo approaches have been tested for the description of the correlated continuum

In the fit process for treating the underlying physics continuum we assume that themain source of this continuum is based on the open heavy-flavor where the way to obtainthe shapes of open charm and beauty are described in section 42 Two possible ways forusing these shapes in the fit process one based on the full description of all processes theother based on a phenomenological approach for the correlated continuum and realisticdescription of processes are considered

The ldquocharm+beautyrdquo approach mdash This approach is based on three assumptions

1 The correlated continuum has only two components open charm and beauty

2 The shapes of the dimuon invariant mass templates for the open charm and beautyprocesses are known with negligible uncertainties (with the same precision as thetemplates for the hadronic cocktail processes)

3 The ratio between the open beauty and the open charm dimuon components isknown (together with its pT and y dependence at the specific energy considered inthe analysis) either from measurements or from tuned models like FONLL or PYTHIA

In this approach the correlated continuum description is associated to one free parameterThe only available measurements for the cc and bb cross-section at forward rapidity comefrom LHCb [3891ndash93] the ratio σbbσcc is (594plusmn 055) middot 10minus2 in good agreement withthe central value of the FONLL prediction (645 middot 10minus2) [86 87]

When considering this approach in the description of the correlated continuum non-negligible tensions between data and MC can be found according to the specific phasespace interval considered These tensions increase towards mid-rapidity while are almostnegligible for the most forward rapidity intervals An example is given in the left-columnplots of figures 59 and 510 where the data-MC comparison is shown for the six y intervals

52 Invariant Mass Fit Procedure 73

considered for the analysis in the pT interval 20 lt pT lt 22 GeVc The same trend isobserved in almost all the considered pT intervals

As a matter of fact these tensions induce an indirect bias on the extraction ofthe signals of interest for the analysis particularly important for the extraction of theω rarr micro+microminus signal For this reason this approach is probably not well-fitted for thisspecific analysis aiming to simultaneously extract the η rarr micro+microminusγ ω rarr micro+microminus andφrarr micro+microminus signals

The semi-empirical approach mdash This new approach has been developed after con-sidering the major limitations of the ldquocharm+beautyrdquo approach in describing the dataover the full rapidity interval available The main difference with respect to the previousapproach is the fact that we abandon any strict physical interpretation of the correlatedcontinuum describing it with an empirical profile flexible enough to saturate the tensionbetween data and MC ensuring a robust extraction of the signals of interest for the anal-ysis This is achieved by describing the correlated continuum by means of two (or more)free parameters each controlling the normalization of an independent empirical shapeThe specific shape of these independent components is not really important still one hasto use sufficiently different mass shapes to ensure enough freedom on the total profile ofthe continuum

Two variants of this semi-empirical approach have been tested in this analysis

bull A 2-component description of the correlated continuum In this case an obviouschoice is to take the two components as the invariant mass distributions of OSdimuons from open charm and open beauty simulations2 This choice allows one tocombine the required smoothness of the continuum invariant mass shape with thekinematical constraints typical of a reconstructed dimuon mass distribution closeto the low-mass threshold this would not have been (easily) achievable with anytrivial combination of analytical parametric functions

bull A 3-component description of the correlated continuum In this variant we add athird component to the two components already considered in the previous case areasonable choice is to take this third component to have the profile of the combi-natorial background evaluated in each pT and y interval considered in the analysis

The results of the data description with these two variants of the semi-empirical ap-proach are shown in figures 59 and 510 in the center and right panels respectively forthe 2- and the 3-component description of the correlated continuum As one can see the2-component description already fixes the tension between data and MC found with theldquocharm+beautyrdquo approach in the full y range Nevertheless the addition of the third de-gree of freedom allowed by the 3-component description of the correlated continuum stillimproves the extraction of the signal in some specific cases see for instance the extractionof the φrarr micro+microminus signal in figures 59b and 59c For this reason the 3-component variantof the semi-empirical approach has been retained as the reference method for the signalextraction for the present analysis

2 It should be clear that in this semi-empirical approach the physical interpretation of any of the twocomponents taken separately is meaningless and must be avoided

74 Chapter 5 Signal Extraction

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 275y250 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 275y250 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 275y250 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 300y275 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 300y275 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 300y275 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(g) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(h) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(i) 300 lt y lt 325

Figure 59 Signal fit for 20 lt pT lt 22 GeVc and various y intervals The first figure of each linecorresponding to the method with the full description of processes the second and third figures ofeach line corresponding to the hybrid method with two or three components respectively

52 Invariant Mass Fit Procedure 75

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6310times

lt 400y375 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(g) 375 lt y lt 400

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6310times

lt 400y375 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(h) 375 lt y lt 400

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6310times

lt 400y375 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(i) 375 lt y lt 400

Figure 510 Signal fit for 20 lt pT lt 22 GeVc and various y intervals The first figure of eachline corresponding to the method with the full description of processes the second and third figuresof each line corresponding to the hybrid method with two or three components respectively

76 Chapter 5 Signal Extraction

523 A Few Examples of Hadronic Cocktail FitsThe detailed breakdown of the MC sources involved in the fit procedure is shown infigure 511 where the data sample considered in the present analysis is integrated over250 lt y lt 400 and 10 lt pT lt 100 GeVc The structures of the η rarr micro+microminusγω rarr micro+microminus and φ rarr micro+microminus processes considered for the estimation of the η ω and φyields are observed to shine out over the underlying continuum Here as well as in thefits presented in the rest of the document the red profile is the sum of the MC sourcesThe uncertainty on the total MC profile is evaluated by combining the uncertainties onthe normalization of each considered source For the processes whose normalization isleft free in the fit this uncertainty is the statistical one resulting from the fit procedureitself for the other processes we propagate the systematic uncertainty on the parameters(branching ratios or cross section ratios) which fix their normalizations to those of thefree processes

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

01

02

03

04

05

610times

γmicromicro

rarrη

γmicromicrorarrη

micromicrorarrη

micromicrorarrρ0πmicromicrorarrω

micromicrorarr

ω

micromicrorarrφ

continuumcorrelated

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

lt 400y250 lt

c lt 1000 GeVT

p100 lt = 13 TeVsALICE pp

lt 40y25 lt

c lt 100 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y250 lt

c lt 1000 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 40y25 lt

c lt 100 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y250 lt

c lt 1000 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

Figure 511 Example of hadronic fit in 250 lt y lt 400 and 10 lt pT lt 100 GeVc

The shape of the dimuon invariant mass spectrum changes significantly according tothe considered pT-y interval In particular at very low-pT and towards central rapiditythe acceptance constraints imposed by the detector deplete the mass spectrum near thekinematic threshold For this reason some of the processes are not measurable in specificregions of the phase space as it could be expected by inspecting the pT-y profiles of the(Atimes ε) reported in figures 43 and 47 In addition at high-pT one observes a decrease ofthe ratio of the hadronic cocktail over the correlated continuum which could be attributedto the decrease of the ratio of the light flavor sources (composing the hadronic cocktail)over the heavy flavor ones (contributing to the correlated continuum) The full evolutionof the dimuon invariant mass spectrum profile as a function of pT and y can be appreciated

52 Invariant Mass Fit Procedure 77

by considering the plots in appendix C In figure 512 we report a few examples illustratingthe discussed point

(a) 00 lt pT lt 02 GeVcand 375 lt y lt 400

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 04 lt pT lt 05 GeVcand 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 20 lt pT lt 22 GeVcand 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

310times

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 40 lt pT lt 45 GeVcand 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 70 lt pT lt 80 GeVcand 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 80 lt pT lt 100 GeVcand 250 lt y lt 275

Figure 512 A few examples of hadronic fit in several pT and y intervals

Chapter 6

Systematics Evaluation

Summary61 Systematics on the Signal Extraction 80

611 Relative Branching Ratio of two-body and Dalitz Decays for the ηand ω Mesons 80

612 σηprimeσφ Cross-Section Ratio 80

613 σρσω Cross-Section Ratio 81

614 Upper limit of the fit 81

615 The correlated continuum shape 81

616 Systematic Uncertainty Computation 82

62 Systematics from the MC input 82

63 Systematics on Trigger Efficiency 83

631 Evaluation of the Trigger Response Function 83

632 Results 84

64 Systematics on Tracking Efficiency 85

641 Preliminary Check 85

642 Tracking Efficiency Evaluation 86

643 MC parametrization 88

644 Results 89

65 Summary of Systematic Uncertainty 89

In this chapter all the systematics sources of the present analysis are presented Twomain groups of systematics uncertainties have been studied

bull the sources contributing to the systematics uncertainty on the signal extraction

bull the sources contributing to the systematics on the (Atimes ε) evaluation

In the first group we include the uncertainties on the parameters involved in thefit procedure (see section 52) relative branching ratios cross-section ratios correlatedcontinuum shape fit range In the second group we include the uncertainties on thekinematic input of the MC simulations on the tracking efficiency and the trigger response

80 Chapter 6 Systematics Evaluation

61 Systematics on the Signal ExtractionIn order to define the systematics tests on the signal extraction a reference scenario hasbeen defined based on the reference values of the parameters involved in the fit procedureFor each parameter one or more alternative values have been considered each systematictest is defined by the variation of one parameter only while the others are kept fixedto their reference value In total 10 systematic tests have been considered the totalsystematic uncertainty on the number of η rarr micro+microminusγ ω rarr micro+microminus and φ rarr micro+microminus

dimuons was taken as the standard deviation of the values resulting from these tests

Syst test reference value alternative value(s)BR ηrarr micro+microminus PDG PDG minus1σ PDG +1σBR ωrarr micro+microminusπ0 PDG PDG minus1σ PDG +1σRatio σηprimeση 0295 minus50 +50Ratio σρσω 10 minus10 +10Upper fit limits 15 GeVc2 20 GeVc2

Templates for thecorrelated contin-uum components

ccrarr micromicro from PYTHIAbbrarr micromicro from PYTHIA

OS from evt mix (data)

ccrarr micromicro from FONLLbbrarr micromicro from FONLL

OS from combinatorial bkg (MC)

Table 61 Summary of systematics tests

611 Relative Branching Ratio of two-body and Dalitz Decaysfor the η and ω Mesons

This systematics test reflects the uncertainty on the ratio between the branching ratio ofthe two-body and Dalitz decay channel of the η and ω mesons In this analysis this testwas implemented by varying the branching ratio of the η rarr micro+microminus and ω rarr micro+microminusπ0

processes by plusmn1σ where σ is the uncertainty on the measurement reported by the PDG(shown in tables 42 and 43) resulting in four independent alternative fits on the data

The variation of the ηrarr micro+microminus branching ratio was found to have a negligible impacton the extraction of η rarr micro+microminusγ and φ rarr micro+microminus signals and a limited impact on theextraction of the ωrarr micro+microminus signal of the order of 1 On the contrary the variation oftheωrarr micro+microminusπ0 branching ratio by plusmn1σ has an average impact of plusmn3 for the extractionof ηrarr micro+microminusγ and ωrarr micro+microminus signals and negligible for the φrarr micro+microminus signals

612 σηprimeσφ Cross-Section Ratio

The ratio σηprimeσφ was varied by plusmn50 to take into account the general lack of mea-surements for this ratio and the differences between the predictions from the availablephenomenological models PYTHIA6 and PHOJET The impact of the considered plusmn50 vari-ation has been observed to be in average ∓2 for the ωrarr micro+microminus signal and negligiblefor the φrarr micro+microminus and ηrarr micro+microminusγ signal

61 Systematics on the Signal Extraction 81

613 σρσω Cross-Section RatioThe uncertainty on the σρσω ratio has been taken from the existing measurements atlower energy [88ndash90] The absence of any strong theoretical argument in favor of animportant energy dependence of this ratio allowed us to take a plusmn10 for the associateduncertainty As expected the impact of this plusmn10 variation is non-negligible only for theextraction of theωrarr micro+microminus signal which is affected by a corresponding ∓2 uncertainty

614 Upper limit of the fitThe lower limit of the invariant mass fit range has been set to the 2mmicro kinematic thresholdin order to be sensitive to the full structure of the η rarr micro+microminusγ decay For the upperlimit a reference value has been set at 15 GeVc2 this value is a trade-off betweenbeing sensitive to the full width of the φ rarr micro+microminus peak and limiting the impact of thecontinuum region between the φ and Jψ resonance where no signal of interest for thelight-neutral mesons can be extracted To study the systematic uncertainty linked to thechoice of the upper limit of the fit range an alternative value has also been defined at20 GeVc2 The corresponding average impact on the extraction of the signals of interestis -3 -12 and -4 respectively for the η rarr micro+microminusγ ω rarr micro+microminus and φ rarr micro+microminus

signals

615 The correlated continuum shape

]2c [GeVmicromicroM0 02 04 06 08 1 12 14

[au

]micromicro

dNd

M

0

5

10

15

20

25

3minus10times

from OS mixing

(PYTHIA)bfrom b

(PYTHIA)cfrom c

(a) Reference

]2c [GeVmicromicroM0 02 04 06 08 1 12 14

[au

]micromicro

dNd

M

0

5

10

15

20

25

3minus10times

microfrom OS MC uncorr

(FONLL)cfrom c

(FONLL)bfrom b

(b) Alternative

Figure 61 Normalized shape of continuum templates

The shape of the correlated continuum is determined by the fit by optimizing therelative weight of three invariant mass templates as explained in section 522 To eval-uate the systematic uncertainty associated to the choice of this set of templates analternative set of templates have been considered The alternative templates correspond

82 Chapter 6 Systematics Evaluation

to the reconstructed open charmbeauty dimuons generated with the lower limit of theFONLL prediction range (offering the largest deviation from the corresponding referencetemplates see figure 412) and to the OS dimuons from the MC simulations of uncor-related muons already considered for the validation of the event mixing technique (seesection 512) Considering the alternative set of templates has an average impact of minus1for the ηrarr micro+microminusγ 2 for the ωrarr micro+microminus and 9 for the φrarr micro+microminus signals

616 Systematic Uncertainty ComputationAs already mentioned the systematic uncertainty on the signal extraction is computedseparately for the η rarr micro+microminusγ ω rarr micro+microminus and φ rarr micro+microminus processes as the standarddeviation of the distribution of value obtained from the systematic tests described above

σ2 = 1N

testssumi

(xi minus 〈x〉)2 (61)

where xi is the outcome of the i-th systematic test out of the N available tests andthe expectation value 〈x〉 is taken as the outcome of the reference fit This approach isjustified by the assumption that for each source of systematics the associated uncertaintycan be assumed to be Gaussian This evaluation is done for each pT-y interval consideredin this analysis

The global uncertainty on the signal extraction is reported in table 62 for the threesignals extracted with the fit procedure since its value depends on the pT and y intervalthe minimum and maximum values are quoted The average uncertainties correspondingto the considered systematic tests on the signal extraction are also reported in the table

Syst test ηrarr micro+microminusγ ωrarr micro+microminus φrarr micro+microminus

BR ηrarr micro+microminus lt 1 2 2 BR ωrarr micro+microminusπ0 3 3 2 Ratio σηprimeσφ lt 1 3 2 Ratio σρσω 1 2 2 Upper fit limit 5 6 8 Templates for the correlatedcontinuum 6 4 5

Standard deviation from (61) 1 - 22 2 - 12 1 - 16

Table 62 Summary of the systematic tests considered on the signal extraction procedure

62 Systematics from the MC inputThe first source of systematic uncertainty considered for the (Atimes ε) evaluation is thechoice of the input kinematic distributions assumed in MC simulations for the generatedη ρ ω ηprime and φ mesons see section 411 The reference choice being the correlated

63 Systematics on Trigger Efficiency 83

pT-y input from PHOJET the alternative MC input has been based on parametrized non-correlated pT and y distributions form PYTHIA6 The corresponding systematic uncer-tainty has been evaluated for each pT and y interval considered in this analysis by takingthe difference of the (Atimes ε) value estimated with the reference and the alternative MCinputs The corresponding average impact on the extraction of the signals of interest is5 55 and 1 respectively for the ηrarr micro+microminusγ ωrarr micro+microminus and φrarr micro+microminus signals

63 Systematics on Trigger Efficiency

The systematics on the trigger efficiency has been determined by comparing the proba-bility of reconstructing dimuons of a given kinematics with two different trigger responsefunctions one obtained from the data and the other from MC simulations The standardprocedure to estimate the systematic uncertainty from the trigger response function canbe summarized as follows

bull Fit the ratio low-pTA-pT obtained dividing the pT distribution of single muonsmatching the low-pT trigger condition by the pT distribution of single muons match-ing the A-pT condition (see paragraph e on section 223) This ratio is evaluatedboth in data and in realistic MC simulations and the corresponding fits define thetrigger response function

bull Select muons matching the A-pT trigger condition in the MC simulation of a specificdimuon signal and weigh each of them (according to their pT) by either the dataor the MC trigger response function

bull Extract the number of reconstructed dimuons under the two assumptions of thetrigger response function The difference is the systematics uncertainty of the triggerefficiency

631 Evaluation of the Trigger Response Function

The definition of the trigger response function given above cannot be used in the presentanalysis because in the considered data set the low-pT and the A-pT trigger matchingconditions coincide Therefore an alternative definition of the trigger response function isadopted here namely the ratio low-pTAll where the denominator is the pT distributionof All reconstructed muons imposing no trigger matching condition

Unfortunately this new definition of the trigger response function cannot be safelyapplied to the data because the All muon sample is contaminated by a non-negligiblehadronic component In this case one can still estimate the low-pTAll for the datastarting from the ratio of the corresponding MC ratio through a dataMC conversionfactor This conversion factor is defined as the ratio between the trigger response functionslow-pTA-pT of data and MC estimated in a dataset (B) as close as possible to the one(A) considered in the present analysis and characterized by different thresholds for the

84 Chapter 6 Systematics Evaluation

low-pT and A-pT trigger matching conditions

low-pT

All

∣∣∣∣∣data

A

(pT) = low-pT

All

∣∣∣∣∣MC

A

(pT)timeslow-pTA-pT

∣∣∣dataB

(stimes pT)low-pTA-pT

∣∣∣MC

B(stimes pT)

(62)

with the pT dependence of the trigger response functions in the reference dataset B beingldquostretchedrdquo by the s factor

s = pcutT (MC B)pcutT (MC A) (63)

where pTcut(MC x) is defined as the pT value for which the trigger response function

(low-pTAll or low-pTA-pT respectively for the datasets A and B) reaches half the dif-ference between the maximum and minimum This approach is correct as long as twoassumptions are valid

bull the trigger response per local board does not change with time

bull the relative difference dataMC between the low-pTA-pT trigger response func-tions from data and MC does not change when considering the low-pTAll triggerresponse functions

The low-pTA-pT trigger response functions defining the dataMC conversion factorin equation (62) can be replaced by a parametrization given by the function

F (pT pcutT σ) = 1 + p0 times

erfpT minus pcut

Tsradic

2σs

minus 1 (64)

based on the three free parameters p0 pcutT and σIn the present analysis the reference dataset B has been assumed to be the 2015 Pb-Pb

dataset (restricted to the peripheral collisions in the 60-100 centrality class) taken atradics = 502 TeV this choice is also used in other dimuon analyses based on the pp dataset

atradics = 5 TeV and the p-Pb dataset at radicsNN = 5 mdash 816 TeV

632 ResultsThe two versions of the trigger re-weighting described above produced two alternativeestimations of the (Atimes ε) for the three considered processes For each pT-y cell consideredin the analysis we retained the alternative version giving the largest deviation with respectto the reference value this deviation is shown in the form of a ratio in figure 62 Theabsolute deviation of this ratio is taken as the systematic uncertainty on the triggerefficiency the average values of this uncertainty are 2 06 and 1 respectively forthe ηrarr micro+microminusγ ωrarr micro+microminus and φrarr micro+microminus processes In the analysis this uncertaintyhas been evaluated for each specific pT-y cell considered for the extraction of the signalSystematic uncertainty values as large as 30 were tolerated in this analysis this resultedin the exclusion of the (minus350 lt y lt 325 04 lt pT lt 06 GeVc) interval for theηrarr micro+microminusγ signal affected by a systematic on the trigger efficiency larger than 70

64 Systematics on Tracking Efficiency 85

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

06

07

08

09

1

11

12

13

14 RefTrigg-reweight

γmicromicrorarrη ]εtimes[ A

(a) ηrarr micro+microminusγ

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

06

07

08

09

1

11

12

13

14 RefTrigg-reweightmicromicrorarrω ]εtimes[ A

(b) ωrarr micro+microminus

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

06

07

08

09

1

11

12

13

14 RefTrigg-reweight

micromicrorarrφ ]εtimes[ A

(c) φrarr micro+microminus

Figure 62 Ratio of Atimes ε for original simulation over the re-weighted simulation for estimating thesystematics associated to the trigger efficiency

64 Systematics on Tracking Efficiency

The systematics on tracking efficiency is one of the contributions to the uncertainty on the(Atimes ε) estimation To compute this uncertainty one has to evaluate the ratio betweenthe tracking efficiencies of data and MC

641 Preliminary Check

Before studying the tracking efficiencies in data and MC it must be verified that thestatus of the detector described in the realistic MC simulations is compatible with thestatus of the detector reflected by the data This is done by inspecting the cluster mapsof the tracking chambers in data and MC in this way one can verify whether the deadareas in the data are correctly reproduced in the MC and no additional dead area isintroduced An example of such comparison is shown in figure 63

Another point to be checked is the variation of the high voltage supplied to the track-ing chambers with respect to the value 16 kV corresponding to the nominal operatingconditions During Run 2 indeed some frequent high voltage drops to 14 kV were spot-ted resulting in a degraded efficiency of the chambers Since this intermediate behaviorbetween the full operation and the off status cannot be easily reproduced in MC specificdetector elements being significantly affected by high voltage drops are added to a ldquorejectlistrdquo and excluded from the reconstruction both in data and MC Alternatively when thispathological high voltage behavior only affects a limited fraction of the considered datasample full runs can be excluded it was the case in the present analysis where 4 runsof the LHC16n period were rejected to avoid major discrepancies between data and MC

After checking the agreement between data and MC concerning the detector statusand the behavior of the high voltage it is possible to launch the evaluation of the trackingefficiency both in data and MC

86 Chapter 6 Systematics Evaluation

Figure 63 Comparison between cluster maps of tracking chamber 4 in data (left) and MC (right)

642 Tracking Efficiency EvaluationThe tracking efficiency (εglobal) is computed as the product of the efficiency (εSti) of eachtracking station

εglobal = εSt1 middot εSt2 middot εSt3 middot εSt45 (65)

The fact the efficiencies of stations 4 and 5 are combined together in the efficiency εSt45 isdue to the logic operating mode implemented in the tracking algorithm [7894] requiringone cluster per station for stations 1 2 and 3 and three clusters from the combinedstations 4-5

Ch1 Ch2 Ch3 Ch4 Ch5 Ch6 Ch7 Ch8 Ch9 Ch10

NSt21-1

St1 St2 St3 St4 St5

NSt20-1

NSt21-0

NSt20-0

St45

Figure 64 Sketch showing the arrangement of the chambers into stations and the possible responsesof one station to the passage of a particle

64 Systematics on Tracking Efficiency 87

To evaluate the efficiency of a given station one has to start considering the efficiencyof the chamber composing the station (see section 223 for a more detailed description ofthe muon spectrometer structure) To evaluate the efficiency of each tracking chamberthe assumption is done that its efficiency does not depend on the efficiency of the otherchambers under this assumption the redundancy of the information given by the twochambers of a specific station can be used to determine the efficiency of each chamberseparately Figure 64 shows the possible responses of station 2 to the passage of aparticle Generalizing to the case of an arbitrary station k the reconstructed track canhave a cluster in both chambers (NStk

1-1 ) a cluster either in the first or the second of thetwo stations (NStk

1-0 or NStk0-1 ) or the track does not fulfill the tracking conditions so it is not

reconstructed (NStk0-0 ) Still focusing on station k composed of chamber i and j(= i+ 1)

one can express the number of reconstructed tracks (Ntot each of them crossing stationk due to the conditions imposed by the tracking algorithm) as

Ntot = NStk1-1 +NStk

0-1 +NStk1-0 (66)

Under the assumption that the efficiencies of chambers i and j are independent NStk1-1

NStk1-0 and NStk

0-1 can be expressed as a function of Ntot

NStk1-1 = Ntot middot εChi middot εChj (67)

NStk1-0 = Ntot middot εChi middot (1minus εChj) (68)

NStk0-1 = Ntot middot (1minus εChi) middot εChj (69)

By combining the above equations the efficiencies of chamber i and j are given by

εChi = NStk1-1

NStk1-1 +NStk

0-1εChj = NStk

1-1NStk

1-1 +NStk1-0

(610)

The individual chamber efficiencies can be combined to compute the efficiency of eachstation In the case of the first three stations the efficiency is defined as the probabilityfor a muon to be detected by at least one of the two chambers

εSt1(23) = 1minus(1minus εCh1(35)

) (1minus εCh2(46)

)= εCh1(35) εCh2(46) +

(1minus εCh1(35)

)εCh2(46) + εCh1(35)

(1minus εCh2(46)

) (611)

For the last two stations the efficiency has to be calculated as a whole due to the trackingalgorithm requirements This efficiency is the probability that a muon is detected by atleast three out of the four chambers in the stations the corresponding formula is thegeneralization of equation (611)

εSt45 =10prodi=7

εChi +10sumi=7

(1minus εChi)10prodj=7j 6=i

εChj

(612)

88 Chapter 6 Systematics Evaluation

643 MC parametrization

In order the tracking efficiency estimation in the MC to be reliable the considered para-metric muon generator must be tuned in order to reproduce the reconstructed kinematicsof the single muons measured in pp collisions at

radics = 13 TeV considered in the present

analysis The tuning is performed by means of a recursive procedure illustrated in fig-ure 65 which includes the following steps

1 Run MC simulations of single muons with given input pT and y distributions

2 Compute the (Atimes ε) as a function of pT and y

3 Use the (Atimes ε) to correct the reconstructed muon distributions from data

4 Compute the ratio as a function of both pT and y between the corrected datadistribution and the kinematic distributions considered for the MC input Shouldthis ratio be compatible with one convergence is reached and the procedure isstopped

5 Inject the corrected pT and y data distributions as the new input for MC simulation

until step 4 is equal to one

First Set of MC simulation

MC gen distribMC rec distrib

MC (Atimes ε)Rec

data distrib

Data corr distrib

Datacoor distrib =MC gen distrib

Data corr distrib rarr MC gen distrib

Done

1

2

3 34

No

Yes

51

Figure 65 Illustration of the data driven method used to tune the input distribution of single muon

65 Summary of Systematic Uncertainty 89

644 ResultsTracking efficiency estimations from the data and from the tuned MC simulation areshown in figure 66 as a function of pT y the azimuthal angle ϕ and the run number A2 systematic uncertainty is observed in average for single muon from the comparisonbetween data and MC For the dimuon signals the systematic uncertainty on the trackingefficiency is estimated to be twice the systematics on the single muons in this case thisresults in a 4 systematic uncertainty independent of pT and y

run number

2536

59

2541

28

2543

78

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

effic

ienc

y

0

02

04

06

08

1

Simulation Data

run number2536

59

2541

28

2543

78

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

EffD

ata

EffS

im

09

1

11

B TeyssierWork Thesis

Figure 66 Tracking efficiency measured in data and in the tuned MC simulation as a function ofrun number

65 Summary of Systematic UncertaintyIn table 63 are summarized the various sources of systematic uncertainties discussed inthis chapter For each of these sources and each signal of interest for this analysis wereport the value of the systematic uncertainty when the uncertainty values depend onthe pT or the y interval their maximum and minimum values are quoted

Syst source η ω φ

Signal extraction 1 - 22 2 - 12 1 - 157 MC input 5 55 1 Trigger efficiency 1 - 31 1 - 24 1 - 25 Branching ratio 13 2 1 Tracking efficiency 4 Luminosity 5

Table 63 Summary of the systematic uncertainty sources contributing to the measurement of theη ρω and φ meson cross-section

Chapter 7

Light Neutral Meson Production

Summary71 Estimation of the Number of Generated Mesons 91

711 The Two-Body Decay Case 91712 The Dalitz Decay Case 92

72 Cross-Section Production for Light Neutral Mesons 93

721 Double-Differential η Meson Production 93722 ρω Meson Production 94723 Double-Differential φ Meson Production 98

This chapter describes the steps followed to convert the reconstructed signal into cross-section for the η ρω and φ mesons The pT dependence of the production cross-sectionis extracted in six y intervals and compared to the predictions of the available modelsIn the case of the φ and ρω mesons the pT dependence of the rapidity-integratedcross-section is also derived allowing for the comparison with the results from existingmeasurements in pp collisions in the same rapidity range

71 Estimation of the Number of Generated MesonsThe very first step after signal extraction consists in correcting the number of recon-structed dimuons for the Atimesε evaluated with the MC simulations discussed in section 41In the case of the two-body decays ρω rarr micro+microminus and φ rarr micro+microminus the information onthe dimuons can be directly converted into the corresponding information on the parentmesons by correcting for the branching ratios of the involved decays In the case of theDalitz decay ηrarr micro+microminusγ an additional step is required to convert the dimuon kinematicsto the η meson one before correcting for the branching ratio

711 The Two-Body Decay CaseAs far as the two-body decays of the ρω and φ mesons are concerned the corrected num-ber of mesons (Nρω and Nφ respectively) corresponding to the reconstructed dimuonsN recmicromicro is given for each pT-y interval considered in this analysis by the following formula

Nρω φ(pT y) =N recmicromicro (pT y)

[Atimes ε]micromicro (pT y) middotBRmiddot ∆pT middot ∆y (71)

92 Chapter 7 Light Neutral Meson Production

where [Atimes ε]micromicro (pT y) is the product of the acceptance and the dimuon reconstructionefficiency evaluated in the specific pT-y cell BR is the branching ratio of the considereddecay channel (see table 43) and ∆pT middot ∆y are the widths of the pT-y cell For theestimation relative to the ρω mesons N rec

micromicro (pT y) [Atimes ε]micromicro (pT y) and the BR arereferred to the ωrarr micro+microminus decay

712 The Dalitz Decay Case

When dealing with the Dalitz decay of the η we start by correcting the number ofreconstructed dimuons for the Atimes ε and the widths of the considered pT-y cell

Ngenmicromicro (pT y) =

N recmicromicro (pT y)

[Atimes ε]micromicro (pT y) middot ∆pT middot ∆y (72)

Contrary to the two-body case the corrected kinematics distribution of the dimuon doesnot coincide with the one of the parent meson due to the Dalitz decay kinematics implyinga third body

)ηyηT

pId(0 50 100 150 200 250 300

)micromicroymicromicro T

pId

(

0

50

100

150

200

250

300

1

10

210

310

410

510

610

710

810

)micromicroy micromicroT

p ηy ηT

pT(

Figure 71 Correlation matrix T(pηT yη pmicromicroT ymicromicro) represented in cell coordinates

72 Cross-Section Production for Light Neutral Mesons 93

So to obtain the correct kinematic distributions of the parent η meson an additionaltransformation is needed

Nηrarrmicromicroγ(pT y) = Tminus1 middot Ngenmicromicro (pT y) (73)

where Tminus1 is the inverse of the matrix encoding the correlation between the kinematics ofthe parent η meson and the one of the dimuon both expressed in terms of pT and y TheT(pηT yηp

micromicroT y

micromicro) is shown in figure 71 each T(pηT yη pmicromicroT y

micromicro) element of the matrix isdefined as the probability of an η meson with a given (pηT yη) kinematics to produce adimuon with a given (pmicromicroT ymicromicro) kinematics so that one can write

Ngenmicromicro (pT y) = Tmiddot Nηrarrmicromicroγ(pT y) (74)

from which equation (73) is derived The row-column indexes of the elements of theTmatrix identify a specific pηT yη and pmicromicroT ymicromicro cell respectively In this specific analysisthe phase space limits considered for both the η and the dimuon are 20 lt y lt 45 and00 lt pT lt 150 GeVc in this way any possible edge effect affecting the numericalproblem will have a limited impact on the phase space covered by the available data

Once the correction expressed by equation (73) is performed the resulting kinematicdistribution is further scaled for the η rarr micro+microminusγ branching ratio in order to obtain thecorrect normalization for the Nη(pT y) distribution

72 Cross-Section Production for Light NeutralMesons

The Nηρωφ(pT y) distributions obtained after correcting for the Atimesε and the branchingratio (and for the meson-dimuon kinematic correlation in the case of the η) must be furthernormalized to the integrated luminosity Lint corresponding to the analyzed data sample(the evaluation of the integrated luminosity is discussed in section 32) This normalizationallows one to obtain the cross-section for the three mesons

d2σ(pT y)dpTdy = Nηρωφ(pT y)times 1

Lint (75)

721 Double-Differential η Meson Production

In figure 72 the pT distributions of the dimuon coming from the η rarr micro+microminusγ decay areshown for the six y interval considered in this analysis These distributions representthe Ngen

micromicro (pT y) input from which the kinematic distribution of the parent meson can beextracted via equation (73) The implementation in the current analysis of the kinematiccorrection based on equation (73) is however still under way for this reason no resulton the η meson cross-section is shown in the rest of the chapter

94 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

ydT

pd η

dN

510

710

910

1110

13100250 lt y lt 275 x 101275 lt y lt 300 x 102300 lt y lt 325 x 103325 lt y lt 350 x 104350 lt y lt 375 x 105375 lt y lt 400 x 10

B TeyssierWork Thesis

Figure 72 Comparison of the pT distribution of η dimuon generated as a function of y

722 ρω Meson ProductionFor the ρω mesons the double-differential pT-y production cross-section has been eval-uated in the available phase space the results are shown in figure 73 as a function ofpT in six y intervals For each y interval the measured cross-section has been comparedto the predictions of PYTHIA8-Monash2013 [95] and PHOJET The comparison is shown inthe panels of figure 74 the two models systematically overestimate by a factor sim 2 thedata in the full accessible pT range for each of the considered y intervals

In figure 75 the y dependence of the production cross-section is shown integratedover the pT range 20 lt pT lt 65 GeVc common to the considered y intervals Thecomparison with the predictions from PYTHIA8-Monash2013 and PHOJET confirms thatthe models overestimate the data by a factor sim 2 Besides the global overestimation thePHOJET prediction seems to provide a better description than PYTHIA8-Monash2013 of they dependence of the data

The ρω production cross-section was also measured in ALICE in pp collisions atradics =

7 TeV integrated over 25 lt y lt 40 as a function of pT in the 10 lt pT lt 50 GeVcrange In order to compare our data to the ones at

radics = 7 TeV the production cross-

section measured in this analysis has been integrated over the full accessible 25 lt y lt 40range As it can be seen from figure 73 the integration over 25 lt y lt 40 was possiblelimited to the 20 lt pT lt 65 GeVc range The comparison between the two energiesshows that the 13 TeV cross-section is larger than the 7 TeV one by a factor sim 2 seefigure 76

72 Cross-Section Production for Light Neutral Mesons 95

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

210

310

410

510

610

0250 lt y lt 275 x 10

1275 lt y lt 300 x 10

2300 lt y lt 325 x 10

3325 lt y lt 350 x 10

4350 lt y lt 375 x 10

5375 lt y lt 400 x 10

B TeyssierWork Thesis

Figure 73 Comparison of the pT distribution of ω meson as a function of y

96 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

375 lt y lt 400

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

3minus10

2minus10

1minus10

1

10350 lt y lt 375

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

325 lt y lt 350

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

300 lt y lt 325

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

275 lt y lt 300

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

250 lt y lt 275

Pythia8

PHOJETB Teyssier

Work Thesis

Figure 74 pT distributions of ω meson for various y intervals

72 Cross-Section Production for Light Neutral Mesons 97

y4minus 2minus 0 2 4

[mb]

yωσd

0

05

1

15

2

25

3

(reflected)ω

(measured)ω

Pythia8 - monash2013

Phojet

c lt 65 GeVT

p20 lt

B TeyssierWork Thesis

Figure 75 y distribution of ω meson integrated in 20 lt pT lt 65 GeVc

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσ2 d

3minus10

2minus10

1minus10

1

=7TeVspp at

=13TeVspp at

B TeyssierWork Thesis

Figure 76 pT distribution of ω meson integrated in y and comparison with measurements at7 TeV [43]

98 Chapter 7 Light Neutral Meson Production

723 Double-Differential φ Meson ProductionAs for the ρω mesons the double-differential pT-y production cross-section has beenevaluated for the φ meson too in the available phase space the results are shown infigure 77 as a function of pT in the y intervals considered in the analysis extended at mid-rapidity with the φ rarr K+Kminus measurements [96] The comparison of the data with thepredictions of the PYTHIA8-Monash2013 and PHOJET models is shown for each y intervalconsidered in the analysis in the panels of figure 78 contrary to what observed for theω meson the PYTHIA8-Monash2013 prediction provides a good description of the dataThe PHOJET prediction on the contrary still slightly fails in estimating the normalizationand the shape of the pT dependence of the production cross-section

The y dependence of the production cross-section is shown in figure 79 integratedover the pT range 20 lt pT lt 65 GeVc common to the considered y intervals As one cansee the data points sit between the predictions from PYTHIA8-Monash2013 and PHOJETwhich both slightly fail in describing the shape of the y dependence The results for theφ meson production in the dikaon channel provide an additional point at mid-rapiditywhich could be compared to the forward measurements presented here

Results for the φ meson production cross-section are also available from ALICE mea-surements in pp collisions at

radics = 276 502 7 and 8 TeV integrated over 25 lt y lt 40

as a function of pT in various pT ranges In order to compare our data to the ones atlower energies the φ meson production cross-section measured in this analysis has beenintegrated over the full accessible 25 lt y lt 40 range As it can be seen from figure 77this integration was possible limited to the 20 lt pT lt 65 GeVc range As expected thecross-section at 13 TeV is found to be larger than the measurements at lower energies

The energy dependence of the φ meson production cross-section has been studiedintegrating the present measurement over the y and pT ranges 25 lt y lt 40 and15 lt pT lt 50 GeVc common to the data at the various available energies Theresults are shown in figure 711 compared with the PYTHIA8-Monash2013 and PHOJETprediction the trend as a function of

radics is found to be approximately linear in the con-

sidered energy range with the PHOJET model in good agreement with the data and thePYTHIA8-Monash2013 prediction systematically underestimating the results The analysisstrategy at 13 TeV is being slightly revised in order to reduce the systematic uncertaintyassociated to the integrated cross-section by optimizing the integration procedure namelyintegrating over the rapidity before signal extraction

72 Cross-Section Production for Light Neutral Mesons 99

]c [GeVT

p0 2 4 6 8 10 12

)]c [m

b(G

eV

ydT

pd φσd

4minus10

3minus10

2minus10

1minus10

1

10

210

310

410

510

-1|lt05 x 10y |-

K+ Krarrφ0250 lt y lt 275 x 10

1275 lt y lt 300 x 10

2300 lt y lt 325 x 103325 lt y lt 350 x 10

4350 lt y lt 375 x 10

5375 lt y lt 400 x 10

B TeyssierWork Thesis

Figure 77 Comparison of the pT distribution of φ meson as a function of y extended at mid-rapidityby the φrarr K+Kminus measurements [96]

100 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1375 lt y lt 400

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

350 lt y lt 375

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1325 lt y lt 350

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

300 lt y lt 325

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

275 lt y lt 300

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

250 lt y lt 275

Pythia8

PHOJETB Teyssier

Work Thesis

Figure 78 pT distribution of φ meson for various y intervals

72 Cross-Section Production for Light Neutral Mesons 101

y4minus 2minus 0 2 4

[mb]

y φσd

0

01

02

03

04

05

(refkected)φ (dikaon measurement)φ (measured)φ

Pythia8 - monash2013

Phojet

c lt 65 GeVT

p20 lt

B TeyssierWork Thesis

Figure 79 y distribution of φ meson integrated in 20 lt pT lt 65 GeVc extended at mid-rapidityby the φrarr K+Kminus measurements [96]

102 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσ2 d

3minus10

2minus10

1minus10

1 =276TeVspp at

=5TeVspp at

=7TeVspp at

=8TeVspp at

=13TeVspp at

lt 40y25 lt

B TeyssierWork Thesis

Figure 710 φ meson pT distribution integrated over 25 lt y lt 40 in pp collisions atradics = 13 TeV

(this analysis) compared to previous measurements at lower energies

72 Cross-Section Production for Light Neutral Mesons 103

B TeyssierWork Thesis

Figure 711 Energy dependence of the φ meson production cross-section in 25 lt y lt 40 and15 lt pT lt 50 GeVc

Conclusions and Perspectives

This work focused on the study of the production cross-section of the η ρω and φmesons This study has been achieved by performing a double-differential pT-y analysisin the phase space available for each meson Results have been compared to the availabletheoretical predictions from the PYTHIA8 and PHOJET models this comparison resultedin a better datamodel agreement for the φ meson than for the ρω meson Moreoverexisting results at several lower collision energies in the same y interval allowed toinvestigate the energy evolution of the production cross-section for the φ meson andlimited to the comparison with the

radics = 7 TeV results for the ρω mesons For the φ

meson the energy evolution of the production cross-section integrated over 25 lt y lt 40and 15 lt pT lt 50 GeVc was found to be approximately linear with the PHOJET modelin good agreement with the data and the PYTHIA8-Monash2013 prediction systematicallyunderestimating the results In a next future the results for the φ meson from thepresent analysis could also be compared to the mid-rapidity measurement performed inALICE in the dikaon channel

The present analysis did not exploit the full potential of the large data sample availablein pp collisions at

radics = 13 TeV which could possibly profit from the combination of the

2016 and 2017 data taking Among the measurements which could still be performedbased on the analysis of the low-mass dimuon region one can cite

bull the study of the multiplicity dependence of the light-neutral meson production

bull the search for strangeness enhancement collective phenomena and azimuthalanisotropies in light-neutral meson production in high-multiplicity pp events

bull the study of the light-neutral meson polarization

Finally beyond the standard dimuon analyses the large pp data sample atradics = 13 TeV

could also be exploited for the search of the first evidence of the η rarr 2micro+2microminus decayfor which only an upper limit is currently available from literature [4] The proximity ofthe η meson mass to the 4mmicro threshold makes the observation of this decay particularlychallenging and sensitive to the description to the combinatorial background

Appendix A

List of Runs

000253659 000253680 000253682 000253748 000253751 000253755 000253756 000253757000253813 000253819 000253825 000253826 000253832 000253834 000253951 000253956000253957 000253958 000253961 000253978

Table A1 Run list for period LHC16f

000254128 000254147 000254148 000254149 000254174 000254175 000254178 000254193000254199 000254204 000254205 000254293 000254302 000254304 000254331 000254332

Table A2 Run list for period LHC16g

000254378 000254381 000254394 000254395 000254396 000254419 000254422 000254476000254479 000254604 000254606 000254608 000254621 000254629 000254630 000254632000254640 000254644 000254646 000254648 000254649 000254651 000254652 000254653000254654 000254983 000254984 000255008 000255009 000255010 000255042 000255068000255071 000255073 000255074 000255075 000255076 000255079 000255082 000255085000255086 000255091 000255111 000255154 000255159 000255162 000255167 000255171000255173 000255176 000255177 000255180 000255182 000255240 000255242 000255247000255248 000255249 000255251 000255252 000255253 000255255 000255256 000255275000255276 000255280 000255283 000255350 000255351 000255352 000255398 000255402000255415 000255440 000255442 000255447 000255463 000255465 000255466 000255467000255469

Table A3 Run list for period LHC16h

000255515 000255533 000255534 000255535 000255537 000255538 000255539 000255540000255542 000255543 000255577 000255583 000255591 000255592 000255614 000255615000255616 000255617 000255618

Table A4 Run list for period LHC16i

108 Appendix A List of Runs

000256146 000256147 000256148 000256149 000256156 000256157 000256158 000256161000256169 000256204 000256207 000256210 000256212 000256213 000256215 000256219000256222 000256223 000256227 000256228 000256231 000256281 000256282 000256283000256284 000256287 000256289 000256290 000256292 000256295 000256297 000256298000256302 000256307 000256311 000256356 000256357 000256361 000256362 000256363000256364 000256365 000256366 000256368 000256372 000256373 000256415 000256417000256418 000256420

Table A5 Run list for period LHC16j

000256504 000256506 000256510 000256512 000256552 000256554 000256556 000256557000256560 000256561 000256564 000256565 000256567 000256589 000256591 000256592000256619 000256620 000256658 000256676 000256677 000256681 000256684 000256691000256694 000256695 000256697 000256941 000256942 000256944 000257011 000257012000257021 000257026 000257028 000257071 000257077 000257080 000257082 000257083000257084 000257086 000257092 000257095 000257224 000257260 000257318 000257320000257322 000257330 000257358 000257364 000257433 000257457 000257468 000257474000257487 000257488 000257490 000257491 000257492 000257530 000257531 000257540000257541 000257560 000257561 000257562 000257563 000257564 000257565 000257566000257587 000257588 000257590 000257592 000257594 000257595 000257601 000257604000257605 000257606 000257630 000257632 000257635 000257636 000257642 000257644000257682 000257684 000257685 000257687 000257688 000257694 000257697 000257724000257725 000257727 000257733 000257734 000257735 000257737 000257892 000257893000257901 000257912 000257932 000257936 000257937 000257939 000257957 000257958000257960 000257963 000257979 000257986 000257989 000258008 000258012 000258014000258017 000258019 000258039 000258041 000258042 000258045 000258048 000258049000258059 000258060 000258062 000258063 000258107 000258108 000258109 000258113000258114 000258117 000258178 000258197 000258202 000258203 000258204 000258256000258257 000258258 000258270 000258271 000258273 000258274 000258278 000258280000258299 000258301 000258302 000258303 000258306 000258307 000258332 000258336000258359 000258387 000258388 000258391 000258393 000258399 000258426 000258452000258454 000258456 000258477 000258498 000258499 000258537

Table A6 Run list for period LHC16k

000258919 000258920 000258921 000258923 000258931 000258962 000258964 000259086000259099 000259117 000259118 000259162 000259164 000259204 000259261 000259263000259264 000259269 000259270 000259271 000259272 000259273 000259274 000259302000259303 000259305 000259307 000259334 000259339 000259340 000259341 000259342000259378 000259379 000259381 000259382 000259394 000259395 000259396 000259469000259471 000259477 000259649 000259650 000259668 000259697 000259700 000259703000259704 000259705 000259711 000259713 000259750 000259751 000259756 000259788000259789 000259822 000259841 000259842 000259860 000259866 000259867 000259868000259888 000259954 000259961 000259979 000260010 000260011 000260014

Table A7 Run list for period LHC16l

109

000260218 000260240 000260310 000260312 000260313 000260338 000260340 000260351000260354 000260357 000260379 000260411 000260432 000260435 000260437 000260440000260441 000260447 000260471 000260472 000260475 000260476 000260481 000260482000260487 000260490 000260495 000260496 000260497 000260537 000260539 000260540000260541 000260542 000260564 000260586 000260611 000260613 000260614 000260615000260616 000260647

Table A8 Run list for period LHC16m

000260649 000260650 000260657 000260667 000260671 000260672 000260689 000260691000260693 000260695 000260700 000260704 000260710 000260713 000260722 000260723000260727 000260728 000260740 000260741 000260749 000260750 000260751 000260752000260763 000260770 000260777 000260782 000260784 000260786 000260788 000260804000260808 000260809 000260810 000260815 000260913 000260914 000260920 000260934000260935 000260936 000260938 000260960 000260963 000260992 000260993 000261020000261022 000261025 000261026 000261027 000261052 000261055 000261065 000261076000261083 000261088 000261093 000261094 000261095 000261099 000261100

Table A9 Run list for period LHC16n

000262399 000262418 000262419 000262422 000262423 000262424 000262428 000262430000262451 000262487 000262492 000262528 000262532 000262533 000262537 000262563000262567 000262568 000262569 000262570 000262571 000262572 000262574 000262578000262583 000262593 000262594 000262628 000262632 000262635 000262705 000262706000262713 000262717 000262719 000262723 000262725 000262727 000262760 000262768000262776 000262777 000262778 000262841 000262842 000262844 000262847 000262849000262853 000262855 000262858 000263332 000263487 000263490 000263496 000263497000263647 000263652 000263653 000263654 000263657 000263662 000263663 000263682000263689 000263690 000263691 000263737 000263738 000263739 000263741 000263743000263744 000263784 000263785 000263786 000263787 000263790 000263792 000263793000263803 000263810 000263813 000263823 000263824 000263829 000263830 000263861000263863 000263866 000263905 000263916 000263917 000263920 000263923 000263977000263978 000263979 000263981 000263984 000263985 000264033 000264035

Table A10 Run list for period LHC16o

000264076 000264078 000264082 000264085 000264086 000264109 000264110 000264129000264137 000264138 000264139 000264164 000264168 000264188 000264190 000264194000264197 000264198 000264232 000264233 000264235 000264238 000264259 000264260000264261 000264262 000264264 000264265 000264266 000264267 000264273 000264277000264279 000264281 000264305 000264306 000264312 000264336 000264341 000264345000264346 000264347

Table A11 Run list for period LHC16p

Appendix B

Raw-Background Comparison mdashfigures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150

lt 275y250 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 300y275 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 325y300 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

25310times

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B1 Evolution of signal and combinatorial background shapes for 000 lt pT lt 020 GeVc

112 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

lt 275y250 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 300y275 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 325y300 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 375y350 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 400y375 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B2 Evolution of signal and combinatorial background shapes for 020 lt pT lt 040 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 275y250 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5

310times

lt 300y275 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20310times

lt 325y300 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 400y375 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B3 Evolution of signal and combinatorial background shapes for 040 lt pT lt 060 GeVc

113

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 275y250 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 300y275 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 325y300 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

80310times

lt 375y350 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 400y375 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B4 Evolution of signal and combinatorial background shapes for 060 lt pT lt 080 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 275y250 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8310times

lt 300y275 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 325y300 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 350y325 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

80310times

lt 375y350 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

50

310times

lt 400y375 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B5 Evolution of signal and combinatorial background shapes for 080 lt pT lt 100 GeVc

114 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600 lt 275y250 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 300y275 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 325y300 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 350y325 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60310times

lt 375y350 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 400y375 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B6 Evolution of signal and combinatorial background shapes for 100 lt pT lt 120 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 275y250 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 300y275 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

50310times

lt 325y300 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

310times

lt 350y325 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

310times

lt 375y350 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

50310times

lt 400y375 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B7 Evolution of signal and combinatorial background shapes for 120 lt pT lt 160 GeVc

115

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4310times

lt 275y250 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 300y275 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 325y300 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 375y350 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 400y375 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B8 Evolution of signal and combinatorial background shapes for 160 lt pT lt 200 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5310times

lt 275y250 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 300y275 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20310times

lt 350y325 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 375y350 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

310times

lt 400y375 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B9 Evolution of signal and combinatorial background shapes for 200 lt pT lt 240 GeVc

116 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 275y250 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

310times

lt 300y275 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12310times

lt 325y300 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

310times

lt 375y350 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5

310times

lt 400y375 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B10 Evolution of signal and combinatorial background shapes for 240 lt pT lt 280 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 275y250 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 300y275 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 325y300 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5

310times

lt 350y325 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 375y350 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3310times

lt 400y375 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B11 Evolution of signal and combinatorial background shapes for 280 lt pT lt 320 GeVc

117

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25310times

lt 275y250 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 300y275 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 325y300 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 350y325 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 375y350 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 400y375 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B12 Evolution of signal and combinatorial background shapes for 320 lt pT lt 360 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 275y250 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 300y275 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3310times

lt 325y300 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 350y325 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 375y350 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 400y375 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B13 Evolution of signal and combinatorial background shapes for 360 lt pT lt 400 GeVc

118 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 300y275 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 325y300 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 350y325 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 375y350 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800

lt 400y375 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B14 Evolution of signal and combinatorial background shapes for 400 lt pT lt 450 GeVc

119

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800 lt 275y250 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310times

lt 300y275 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 325y300 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310times

lt 350y325 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 375y350 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 400y375 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B15 Evolution of signal and combinatorial background shapes for 450 lt pT lt 500 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 275y250 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 300y275 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310times

lt 325y300 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 350y325 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 375y350 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300 lt 400y375 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B16 Evolution of signal and combinatorial background shapes for 500 lt pT lt 550 GeVc

120 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400 lt 275y250 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 300y275 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 325y300 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 350y325 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800

lt 375y350 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150

200

250

lt 400y375 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B17 Evolution of signal and combinatorial background shapes for 550 lt pT lt 600 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

lt 275y250 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 300y275 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12310times

lt 325y300 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1310times

lt 350y325 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 375y350 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150 lt 400y375 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B18 Evolution of signal and combinatorial background shapes for 600 lt pT lt 650 GeVc

121

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

lt 275y250 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800

lt 300y275 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800 lt 325y300 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600 lt 350y325 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 375y350 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

80

100

120

140

lt 400y375 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B19 Evolution of signal and combinatorial background shapes for 650 lt pT lt 700 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400 lt 275y250 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 300y275 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 325y300 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 375y350 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150 lt 400y375 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B20 Evolution of signal and combinatorial background shapes for 700 lt pT lt 800 GeVc

122 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 300y275 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 325y300 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800 lt 350y325 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 375y350 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150

200

lt 400y375 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B21 Evolution of signal and combinatorial background shapes for 800 lt pT lt 1000 GeVc

Appendix C

Hadronic-Cocktail fits mdash figures

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C1 Hadronic cocktail fits for 000 lt pT lt 020 GeVc

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 350y325 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 040 GeVT

p020 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 375y350 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 040 GeVT

p020 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 400y375 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 040 GeVT

p020 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C2 Hadronic cocktail fits for 020 lt pT lt 040 GeVc

124 Appendix C Hadronic-Cocktail fits mdash figures

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 350y325 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 400y375 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C3 Hadronic cocktail fits for 040 lt pT lt 060 GeVc

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

12

14

310times

lt 350y325 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 080 GeVT

p060 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 375y350 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 080 GeVT

p060 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

25

310times

lt 400y375 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 080 GeVT

p060 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C4 Hadronic cocktail fits for 060 lt pT lt 080 GeVc

125

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 325y300 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

25

310times

lt 350y325 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

50

310times

lt 375y350 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 400y375 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 375 lt y lt 400

Figure C5 Hadronic cocktail fits for 080 lt pT lt 100 GeVc

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

12

14

310times

lt 325y300 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 350y325 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 375y350 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 400y375 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 375 lt y lt 400

Figure C6 Hadronic cocktail fits for 100 lt pT lt 120 GeVc

126 Appendix C Hadronic-Cocktail fits mdash figures

Not available fit in250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

12

310times

lt 300y275 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 325y300 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

50

310times

lt 350y325 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

50

310times

lt 375y350 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 400y375 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 375 lt y lt 400

Figure C7 Hadronic cocktail fits for 120 lt pT lt 160 GeVc

Not available fit in250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 300y275 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 325y300 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 350y325 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30310times

lt 375y350 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

310times

lt 400y375 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 375 lt y lt 400

Figure C8 Hadronic cocktail fits for 160 lt pT lt 200 GeVc

127

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 275y250 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 300y275 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

310times

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 350y325 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 375y350 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 400y375 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C9 Hadronic cocktail fits for 200 lt pT lt 240 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 275y250 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 300y275 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

5

310times

lt 400y375 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C10 Hadronic cocktail fits for 240 lt pT lt 280 GeVc

128 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

310times

lt 275y250 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 300y275 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 325y300 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

5

310times

lt 350y325 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 375y350 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

310times

lt 400y375 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C11 Hadronic cocktail fits for 280 lt pT lt 320 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 275y250 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 300y275 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 325y300 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

310times

lt 350y325 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 375y350 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 400y375 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C12 Hadronic cocktail fits for 320 lt pT lt 360 GeVc

129

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 275y250 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 300y275 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 325y300 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp lt 325y300 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 350y325 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 375y350 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

310times

lt 400y375 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C13 Hadronic cocktail fits for 360 lt pT lt 400 GeVc

130 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 300y275 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp lt 300y275 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times lt 325y300 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times lt 350y325 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

12

310times

lt 375y350 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

800

lt 400y375 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C14 Hadronic cocktail fits for 400 lt pT lt 450 GeVc

131

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

800

lt 275y250 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

12

14310times lt 300y275 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

310times

lt 325y300 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1310times

lt 350y325 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 375y350 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

500

lt 400y375 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C15 Hadronic cocktail fits for 450 lt pT lt 500 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 275y250 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

800

lt 300y275 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 325y300 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 350y325 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 375y350 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 400y375 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C16 Hadronic cocktail fits for 500 lt pT lt 550 GeVc

132 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 275y250 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 300y275 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

500

lt 325y300 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 350y325 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 375y350 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 400y375 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C17 Hadronic cocktail fits for 550 lt pT lt 600 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300 lt 275y250 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 300y275 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 325y300 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 350y325 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 375y350 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 400y375 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C18 Hadronic cocktail fits for 600 lt pT lt 650 GeVc

133

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200 lt 275y250 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 300y275 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 325y300 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 350y325 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 375y350 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

20

40

60

80

100

lt 400y375 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C19 Hadronic cocktail fits for 650 lt pT lt 700 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 275y250 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 300y275 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 325y300 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 375y350 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 400y375 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C20 Hadronic cocktail fits for 700 lt pT lt 800 GeVc

134 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 300y275 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 325y300 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 350y325 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 375y350 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375Not available fit in

375 lt y lt 400

Figure C21 Hadronic cocktail fits for 800 lt pT lt 1000 GeVc

Bibliography

[1] Michael E Peskin and Daniel V Schroeder An Introduction to Quantum FieldTheory Addison-Wesley 3 edition 1951 (Cited pages 1 et 7)

[2] C A Baker D D Doyle P Geltenbort and others Improved Experimental Limiton the Electric Dipole Moment of the Neutron Phys Rev Lett 97(13)131801September 2006 [link] (Cited page 4)

[3] SM Barr A review of CP violation in atoms International Journal of ModernPhysics A 08(02)209ndash236 January 1993 [link] (Cited page 4)

[4] C Patrignani K Agashe G Aielli and others Review of Particle PhysicsChinPhys C40100001 October 2016 [link] (Cited pages 4 5 7 54 56 58et 105)

[5] E Eichten K Gottfried T Kinoshita and others Charmonium The model PhysRev D 17(11)3090ndash3117 June 1978 [link] (Cited page 6)

[6] Gerardrsquot Hooft Symmetry Breaking Through Bell-Jackiw Anomalies PhysRevLett378ndash11 1976 (Cited page 10)

[7] S P Klevansky The Nambu-Jona-Lasinio model of quantum chromodynamics RevMod Phys 64649ndash708 1992 (Cited pages 10 et 12)

[8] P Costa C A de Sousa M C Ruivo and others The QCD critical end pointin the SU(3) NambundashJona-Lasinio model Physics Letters B 647(5)431ndash435 April2007 [link] (Cited page 10)

[9] J Stachel and G R Young Relativistic Heavy ION Physics at CERN and BNLAnnu Rev Nucl Part Sci 42(1)537ndash597 December 1992 [link] (Cited page 13)

[10] H R Schmidt and J Schukraft The physics of ultra-relativistic heavy-ion collisionsJ Phys G Nucl Part Phys 19(11)1705 1993 [link] (Cited page 13)

[11] RHIC Physics of the Relativistic Heavy Ion Collider 2017 [httpswwwbnlgovrhicphysicsasp] (Cited page 13)

[12] CERN Heavy ions and quark-gluon plasma [httpshomecernaboutphysicsheavy-ions-and-quark-gluon-plasma] (Cited page 13)

[13] ALICE Collaboration φ-meson production at forward rapidity in p-Pb collisionsat radicsNN = 502 TeV and in pp collisions at

radics = 276 TeV Physics Letters B

768203ndash217 May 2017 [link] (Cited pages 14 15 et 26)

[14] Michael L Miller Klaus Reygers Stephen J Sanders and others Glauber Model-ing in High-Energy Nuclear Collisions Annu Rev Nucl Part Sci 57(1)205ndash243October 2007 [link] (Cited page 14)

Abstract The ordinary matter surrounding us is made of hadrons which in turn arecomposed of quarks and gluons These latter are elementary constituents which cannotbe observed in a free state However it is at present recognized that this matter confinedwithin hadrons can undergo under extreme conditions of high temperature andor highnet baryonic density a transition to a state of deconfined quarks and gluons which iscalled quark gluon plasma

The conditions required to form this quark gluon plasma can be experimentallyachieved using a machine capable of colliding nuclei at very high energies this is partic-ularly the case at CERN where is located the worldrsquos largest and most powerful particleaccelerator the Large Hadron Collider which collided Pb ions at a center-of-mass energyof 276 to 502 TeV per nucleon pair and protons of 09 to 13 TeV Pb-Pb collisions atsuch relativistic energies definitely allow for the suitable density conditions to form thequark gluon plasma phase

This thesis work contributes to this physics program by studying the production ofneutral light mesons in collisions of proton-proton at 13 TeV which provides the necessaryreference to understand further observations done in Pb-Pb collisions This study has beenperformed in the dimuon decay channel by analyzing the dimuon invariant mass spectrumin the region of masses lower than 15 GeVc2 giving access to the measurement of thecross sections of η ρω and φ meson

Keywords CERN LHC ALICE QGP Chirality Muon Meson StrangenessHadronic Physics High Energy Physics

Eacutetude de la production de meacutesons neutres leacutegers dans la voie de deacutesinteacutegrationdimuonique en collisions proton-proton agrave

radics = 13 TeV agrave rapiditeacute vers lrsquoavant

dans ALICE au LHC du CERN

Reacutesumeacute La matiegravere qui nous entoure est formeacutee de hadrons eux-mecircmes constitueacutesde quarks et de gluons Ces derniers sont des composants eacuteleacutementaires qui nrsquoexistentpas sous forme libre Cependant nous savons agrave lrsquoheure actuelle que la matiegravere confineacuteedans des hadrons peut dans des conditions de haute tempeacuterature etou de haute densiteacutebaryonique se retrouver sous une forme deacuteconfineacutee de plasma de quarks et de gluons

Pour reacutealiser expeacuterimentalement les conditions permettant de former ce plasma dequarks et de gluons nous avons besoin drsquoune machine capable de faire entrer en collisionsdes noyaux agrave des eacutenergies tregraves eacuteleveacutees cela est notamment possible au CERN ougrave se situele plus grand acceacuteleacuterateur de particules du monde le Large Hadron Collider qui a permisde faire entrer en collisions des noyaux de Plomb agrave une eacutenergie par paire de nucleacuteonsde 276 et 502 TeV et des protons agrave des eacutenergies allant de 09 agrave 13 TeV Les collisionsentre noyaux de Plomb permettent en particulier drsquoatteindre les conditions de densiteacutedrsquoeacutenergie neacutecessaires agrave la formation de la phase de plasma de quarks et de gluons

Ce travail de thegravese contribue agrave ce programme de physique par lrsquoeacutetude de la productionde meacutesons neutres leacutegers en collisions proton-proton agrave 13 TeV reacutefeacuterence neacutecessaire pourcomprendre les observations en collisions Plomb-Plomb Lrsquoeacutetude des meacutesons neutres leacutegersa eacuteteacute meneacutee dans le canal dimuonique par lrsquoanalyse du spectre de masse invariante desdimuons de masse infeacuterieure agrave 15 GeVc2 permettant notamment de mesurer les sectionsefficaces des meacutesons η ρω et φ

Mots cleacutes CERN LHC ALICE QGP Chiraliteacute Muon Meacuteson Eacutetrangeteacute PhysiqueHadronique Physique des hautes eacutenergies

Remerciements

Je tiens tout drsquoabord agrave remercier lrsquoIPNL sous la direction de Guy Chanfray ainsi quele groupe ALICE de Lyon sous la direction de Brigitte Cheynis pour mrsquoavoir accueillipendant ces trois anneacutees Je tiens aussi agrave remercier le CNRS pour mrsquoavoir permis defaire cette thegravese gracircce agrave leur financement ainsi que le LAVEX LIO (Lyon Institute ofOrigins) de lrsquouniversiteacute de Lyon pour le serveur de calcul du groupe theacuteorie que jrsquoai eulrsquoopportuniteacute drsquoutiliser

Je voudrais remercier Barbara Erazmus qui a bien voulu ecirctre la preacutesidente de monjury de thegravese Roberta Arnaldi et Philippe Crochet pour avoir eacuteteacute mes rapporteurs quigracircce agrave leurs commentaires ont permis drsquoameacuteliorer la qualiteacute de ce manuscrit Merciaussi agrave Alberto Baldisseri et Hubert Hansen qui ont bien voulu ecirctre examinateurs decette thegravese ce qui a contribueacutee agrave lrsquoameacutelioration du document Je voudrais aussi vousremercier drsquoavoir fait le trajet sur Lyon pour avoir assisteacute agrave ma soutenance

Le groupe ALICE de Lyon mrsquoa permis de reacutealiser cette thegravese dans une bonne ambianceJe remercie Brigitte Cheynis ma directrice de thegravese avec qui jrsquoai pu avoir de nombreusesdiscussions que ce sois sur le VZERO pour ma tacircche de service au sein de la collaborationALICE sur des aspects scientifiques de mon analyse ou tous simplement sur lrsquoactualiteacuteainsi que pour les nombreuses corrections orthographiques que ce sois en anglais ou enfranccedilais qursquoelle a apporteacutees agrave mon travail Je tiens aussi agrave remercier Antonio mon co-encadrant de thegravese qui mrsquoa appris la ponctualiteacute italienne avec qui jrsquoai beaucoup apprissur lrsquoanalyse de donneacutees de ma thegravese et avec qui jrsquoai eu de nombreux eacutechangesdiscussionsque se sois scientifiques ou non Je voudrais aussi remercier Cvetan pour toutes lesdiscussions que jrsquoai pu avoir que ce sois sur le VZERO en lien avec ma tacircche de service ousur la physique hadronique et lrsquoexpeacuterience ALICE Ces discussions mrsquoont permis drsquoeacutelargirma vision du domaine Merci aussi agrave Laurent Ducroux pour les eacutechanges en lien aveclrsquoenseignement ainsi que les conseils apregraves mes diffeacuterentes preacutesentations au laboratoireMerci aussi agrave Raphaeumll pour les divers eacutechanges ainsi que sur lrsquoaide apporteacute durant lapreacuteparation de lrsquooral et agrave Massimiliano pour ces quelques mois au laboratoire en tantque nouveau post-doc du groupe ougrave tes conseils et points releveacutes durant ma preacuteparationdrsquooral ont eacuteteacute utile En plus des permanents et post-doc le groupe agrave accueilli des stagiairesdurant ma preacutesence dans le groupe et jrsquoaimerai les remercier pour la bonne humeur etambiance qursquoils sont apporteacutes tous particuliegraverement ceux qui ont cocirctoyeacute mon bureau quece sois pour deux ou six mois merci agrave Thibault Pierre Demongodin Samuel et AlexandreThyvollet ainsi que Pierre-Etienne et Satya pour leur bonne humeur et leur motivationpour participer au tournoi de volley de lrsquoAPPN

Je souhaiterais aussi remercier Hubert et Alexandre Biguet pour leur eacutechanges sur laQCD et la physique hadronique theacuteorique que jrsquoai pu avoir

Je souhaiterai aussi remercier les membres de lrsquoobservatoire des sciences de lrsquouniversqui mrsquoont permis de reacutealiser une tacircche drsquoenseignement pendant deux ans de ma thegravese

vi

Merci agrave Jean-Philippe Perrillat Jean-Franccedilois Gonzalez et Laurent Ducroux pour mrsquoavoirpris dans leur eacutequipe drsquoenseignement cela a eacuteteacute une expeacuterience tregraves enrichissante

I would like to thank all the ALICE collaboration that allowed me to do this thesisand especially I thank all the collaborators who contributed at the lmmumu PAG inparticular Alessandro Di Falco and Ester Casula from the INFN of Cagliari for theirhelp and advice given during the thesis Satoshi Yano from the Hiroshima university forhis contribution of the pp at 13 TeV In addition to the PAG collaborator I would liketo thanks all the DQ people and in particular Diego Laurent Aphecetch and PhilippePillot for their help in the evaluation of the muon arms systematics Martino for all theenriching exchanges on the operation of the ALICE trigger system and the luminosityEvgeny for his response concerning the physics selection and David for the response onthe multiplicity evaluation I would like to thanks Andreas Elena and Marie qualityassurance coordinator with whom I was in contact for my service task for their kindnessand efficiency during the two and a half years or I participated in the QA as well as fortheir understanding on the delays

Cette thegravese mrsquoa permis de mrsquoimmerger dans la communauteacute franccedilaise de la physiquehadronique notamment gracircce aux rencontre QGP France et je voudrais remerciertoutes les personnes avec qui jrsquoai pu avoir de bonnes discussions lors de ces rencontresnotamment les doctorants et post-doc que jrsquoai pu rencontrer Antoine Astrid AudreyBenjamin Emilie Gabriel Gabriele Jana Julien Lucile Maxime Michael et MohamadCette thegravese mrsquoa permis aussi de faire des rencontres enrichissantes durant les diverseseacutecoles que jrsquoai reacutealiseacutes et je souhaiterai remercier les doctorants qui y ont participeacute pourles bons moments passeacutes dans ces diverses eacutecoles

Bien sucircr je souhaite aussi remercier les doctorants qui ont cocirctoyeacute lrsquoIPNL durant cestrois anneacutees notamment Alexandre Biguet Anne-Laure Bertrand Ceacutecile Elvire Eme-line Franccedilois Guillaume Garilot Guillaume Victor Jean-Baptiste Joffrey Lola NicolasBaillot Nicolas Deutschmann Nicolas Galy Pierre Becker Reacutemi et Solegravene En plus desdoctorants que jrsquoai cocirctoyeacutes je souhaiterai aussi remercier Alain Cleacutement David GeoffreyHubert Martin Sylvie et Yoan pour les nombreuses pauses cafeacute pris ensemble durant cestrois anneacutees ainsi qursquoAntoine pour avoir accepteacute drsquoecirctre mon parrain pour ma thegravese

Merci aussi agrave Aureacutelie Camille Eacuteloiumlse Florian et Laurine pour tous les bons momentsque ce sois les midis en soireacutee durant des films ou des sessions jeux Merci aussi agrave Clairepour toutes ces discussions et soutiens mutuel pour nos thegraveses malgreacute le deacutecalage entrela France et le Breacutesil

Enfin jrsquoaimerais remercier ma famille pour leur soutiens durant toute ma formationuniversitaire ainsi que durant ma thegravese Je suis sucircr que mes grands-parents paternel auraieacuteteacute tregraves fiegravere de me voir arriver jusqursquoagrave ce diplocircme eux qui eacutetaient inquiets de savoir sijrsquoy arriverai ainsi que Christian et Thierry mes oncles auraient eacuteteacute fiegravere et auraient aimeacuteme voir agrave ce niveau

Reacutesumeacute

Ce manuscrit sur mon travail de thegravese commence par un premier chapitre sur les motiva-tions physiques du sujet eacutetudieacute tant sur le plan theacuteorique qursquoexpeacuterimental Dans le deux-iegraveme chapitre je traiterai du collisionneur de particules ayant produit les collisions danslrsquoexpeacuterience ALICE utiliseacutees durant lrsquoanalyse preacutesenteacutee dans ce manuscrit La secondepartie de ce chapitre est justement deacutedieacutee agrave lrsquoappareillage ALICE Le troisiegraveme chapitreporte sur la caracteacuterisation du jeu de donneacutees que jrsquoai exploiteacute ainsi que sur lrsquoeacutevaluationde la luminositeacute inteacutegreacutee correspondant agrave cet eacutechantillon Le quatriegraveme chapitre quant agravelui porte sur les simulations Monte-Carlo qui ont du ecirctre faites pour mener agrave bien cetteanalyse Le cinquiegraveme chapitre sur la meacutethodologie utiliseacutee pour extraire de nos don-neacutees les signaux drsquointeacuterecirct Dans lrsquoavant-dernier chapitre le sixiegraveme nous traiterons delrsquoeacutevaluation des quatre sources de systeacutematiques qui impactent notre analyse Le dernierchapitre traitera des reacutesultats que nous avons pu obtenir en termes de sections efficacesde production de meacutesons neutres leacutegers

Cadre Physique (chapitre 1)Le cadre theacuteorique englobant le travail preacutesenteacute dans ce document est la chromodynamiquequantique deacutecrivant lrsquointeraction forte lrsquoune des quatre interactions fondamentales quenous connaissons agrave lrsquoheure actuelle agissant sur les quarks et les gluons par eacutechangede gluons On verra que cette theacuteorie peut srsquoexprimer matheacutematiquement en termes dedensiteacute Lagrangienne De ce Lagrangien peut ecirctre extraite une symeacutetrie particuliegraverementinteacuteressante pour lrsquoeacutetude des meacutesons leacutegers neutres la symeacutetrie chirale qui sera traiteacutee endeacutetails dans ce chapitre introductif De la chromodynamique quantique peut ecirctre extraitun diagramme thermodynamique de la matiegravere hadronique dans lequel deux principalesphases sont visibles la phase ougrave la matiegravere hadronique se condense sous forme de hadronset la phase partonique ougrave est creacuteeacute un plasma de quarks et de gluons (QGP)

Expeacuterimentalement ce diagramme de phases peut ecirctre eacutetudieacute gracircce agrave des acceacuteleacuterateursde particules permettant de faire des collisions cible fixe etou en mode collisionneurDans la seconde partie de ce chapitre je commencerai par introduire quelques variablescineacutematiques drsquointeacuterecirct pour le domaine ainsi que deux concepts geacuteomeacutetriques qui sont lacentraliteacute de la collision deacutetermineacutee par la distance qui seacutepare les centres des deux noyauxet le plan de reacuteaction de la collision Une collision entre deux noyaux comporte plusieurseacutetapes chronologiques notamment la phase de QGP suivie par deux phases hadroniquesdomineacutees respectivement par des collisions ineacutelastiques et eacutelastiques cela engendre desproductions de particules tregraves diverses Dans la suite du chapitre seront parcourus tousles types de sondes inteacuteressantes pour lrsquoeacutetude des collisions drsquoions lourds jrsquoen profiteraipour faire un petit eacutetat de lrsquoart des mesures faites dans les diffeacuterentes voies drsquoobservationBien sucircr les reacutesultats montreacutes le sont seulement agrave titre drsquoexemple et pas de maniegravereexhaustive

La derniegravere section sur les reacutesultats expeacuterimentaux est focaliseacutee sur la productionde dimuons de basses masses dans ALICE qui fait lrsquoobjet de lrsquoeacutetude rapporteacutee dans ce

viii

manuscrit Dans les preacuteceacutedentes eacutetudes lrsquoaccent eacutetait mis sur le meacuteson φ qui est agrave lrsquooriginedu signal le plus facilement observable dans la reacutegion des basses masses Dans notre caslrsquoeacutetude a eacuteteacute porteacutee sur les meacutesons η ρω et φ car la statistique disponible dans le lotde donneacutees eacutetudieacute est suffisante pour extraire les signaux correspondants

LHC et ALICE (chapitre 2)La premiegravere partie du chapitre 2 sera consacreacutee au LHC notamment au complexedrsquoacceacuteleacuterateurs permettant drsquoinjecter au sein du LHC des noyaux ou des protons Onen profitera pour eacutevoquer les sceacutenarios futurs agrave relativement court terme pour le LHC etpour finir cette courte partie les programmes drsquoions lourds au CERN et plus geacuteneacuteralementdans le monde

La seconde partie du chapitre est deacutedieacutee au deacutetecteur ALICE Cette partie peut ecirctregrossiegraverement coupeacutee en deux parties la premiegravere deacutedieacutee au deacutetecteur actuel et son fonc-tionnement la seconde au programme drsquoameacutelioration qui doit deacutebuter agrave la fin du Run 2du LHC

Luminositeacute et Jeu de Donneacutees (chapitre 3)Dans ce chapitre deux points seront eacutevoqueacutes Le premier porte sur les conditions expeacuteri-mentales pour les donneacutees proton-proton agrave 13 TeV prises en 2016 utiliseacutees dans lrsquoanalysedeacutecrite dans ce manuscrit Le second porte sur lrsquoeacutevaluation de la luminositeacute inteacutegreacuteeCette mesure nous permet drsquoeacutevaluer des sections efficaces de production agrave partir des tauxde production connaissant la section efficace associeacutee agrave la condition de deacuteclenchement debiais minimal de lrsquoexpeacuterience et le nombre drsquoeacuteveacutenements de biais minimal eacutequivalent aujeu de donneacutees consideacutereacute dans lrsquoanalyse Ce chapitre ne traitera pas de lrsquoeacutevaluation decette section efficace de biais minimal qui fait lrsquoobjet drsquoune eacutetude agrave part entiegravere non dis-cuteacute dans ce manuscrit et qui sert agrave toutes les analyses Cette section traitera en deacutetailsde la proceacutedure permettant drsquoavoir le facteur de conversion entre le nombre drsquoeacuteveacutenementsanalyseacutes et le nombre eacutequivalent drsquoeacuteveacutenements de biais minimal

Simulations Monte-Carlo (chapitre 4)Ce chapitre est structureacute en deux parties la premiegravere se focalisant sur les meacutesons neutresleacutegers et la deuxiegraveme sur les simulations des processus de charme et beauteacute ouverte

Dans la partie sur les meacutesons on commencera par donner quelques geacuteneacuteraliteacutes surces particules ainsi que sur le geacuteneacuterateur employeacute dans les simulations Puis on traiteradeux cas drsquointeacuterecirct Le premier cas concerne les processus faisant intervenir trois particulesdans lrsquoeacutetat final de la deacutesinteacutegration (deacutesinteacutegration Dalitz) en mettant lrsquoaccent sur leurfacteur de forme Le second cas quandt agrave lui correspond aux deacutesinteacutegrations agrave deuxcorps dans les canaux dileptoniques et plus particuliegraverement dans celui dimuonique

La seconde partie du chapitre est consacreacutee aux dimuons venant des deacutesinteacutegrationsdes saveurs lourdes ouvertes Un dimuon venant des saveurs lourdes ouvertes est deacutefini

ix

comme deux muons produits durant les chaicircnes de deacutesinteacutegration drsquoune paire quark anti-quark charmeacutes ou beaux On verra dans cette section qursquoun impact visible sur le spectreen masse deacutecoule de la distribution cineacutematique initiale du quark beau ou charmeacute gracircceaux comparaisons que nous avons faites avec des simulations utilisant les distributionscineacutematiques de PYTHIA6 et de FONLL Le dernier point eacutevoqueacute dans ce chapitre concernela longueur de chaicircne de deacutesinteacutegration des hadrons charmeacutes et beaux car nous sommesinteacuteresseacutes agrave reproduire les dimuons venant des paires de charme ou de beauteacute qui sontcorreacuteleacutes Une hypothegravese que nous pouvons faire est que plus une chaicircne de deacutesinteacutegrationest longue plus la correacutelation reacutesultante de la paire est amoindrie On montrera que leprofil de longueur de chaicircne de deacutesinteacutegration possegravede une structure relativement complexeet qursquoil y a un impact sur le spectre en masse en ne consideacuterant qursquoun certain intervallede longueur de deacutesinteacutegration

Extraction du Signal (chapitre 5)Dans ce chapitre deux points seront eacutevoqueacutes le premier sera lrsquoeacutevaluation et la soustractiondu bruit combinatoire le second portera sur la proceacutedure utiliseacutee pour extraire le signal

La composante de bruit combinatoire dans les dimuons de signes opposeacutes aussi appeleacutebruit non-correacuteleacute provient de la meacutethode de construction des dimuons Cette meacutethodeneacutecessite la creacuteation de toutes les paires de dimuons possibles dans un eacuteveacutenement Poureacutevaluer cette composante nous employons la technique du mixage drsquoeacuteveacutenements crsquoest-agrave-dire que nous creacuteons agrave lrsquoaide des donneacutees un lot de dimuons qui par construction serontnon-correacuteleacutes en formant chaque dimuon par combinaison drsquoun muon drsquoun eacuteveacutenement avecun muon drsquoun autre eacuteveacutenement La distribution ainsi obtenue est normaliseacutee agrave partir desdistributions de dimuons de mecircmes signes Cette proceacutedure agrave eacuteteacute valideacutee agrave lrsquoaide desimulations Monte-Carlo Une fois la soustraction du bruit faite pour chaque intervalleen pT et y consideacutereacute dans notre analyse nous pouvons passer agrave lrsquoextraction du signal

Pour extraire le signal drsquointeacuterecirct de notre spectre de dimuons correacuteleacutes nous utilisonsune proceacutedure drsquoajustement par minimisation du χ2 Cette proceacutedure est baseacutee sur unefonction servant agrave lrsquoajustement qui est composeacutee des distributions en masse des pro-cessus hadroniques composant notre cocktail hadronique Nous verrons notamment parquel moyen nous arrivons agrave reacuteduire le nombre de degreacutes de liberteacute de notre fonction enasservissant certaines composantes agrave drsquoautres Une grande partie de ce point est consacreacuteeau traitement du continuum correacuteleacute et aux meacutethodes permettant de deacutecrire la forme dela fonction modeacutelisant le continuum correacuteleacute

Eacutevaluation des Systeacutematiques (chapitre 6)Ce chapitre est diviseacute en quatre parties une pour chaque contribution agrave la systeacutematiquede notre analyse

La premiegravere partie traitera de la systeacutematique sur lrsquoextraction du signal et notammentsur lrsquoeacutevaluation de la systeacutematique sur tous les choix que nous avons faits pour reacutealisernotre ajustement Pour cela un ou plusieurs tests sont faits en modifiant agrave chaque foisun seul paramegravetre par rapport agrave notre ajustement de reacutefeacuterence Une fois tous les tests

x

reacutealiseacutes pour un intervalle en pT-y consideacutereacute dans cette analyse on eacutevalue par la meacutethodede deacuteviation standard lrsquoerreur systeacutematique qui en reacutesulte

Les autres parties traiteront de la systeacutematique lieacutee agrave lrsquoestimation du produit delrsquoacceptante geacuteomeacutetrique et de lrsquoefficaciteacute de reconstruction notamment le choix de lrsquoinputcineacutematique pour les simulations Monte-Carlo lrsquoincertitude sur lrsquoefficaciteacute du systegraveme dedeacuteclenchement et sur lrsquoefficaciteacute du systegraveme de trajectographie

Reacutesultats (chapitre 7)Dans ce dernier chapitre avant de parler des reacutesultats nous discuterons la correction dusignal extrait des distributions de masse invariante reconstruit pour lrsquoestimation de lasection efficace de production Nous passerons ensuite aux reacutesultats en preacutesentant et endiscutant la deacutependance en pT et y de la section efficace de production des meacutesons ηρω et φ Les reacutesultats obtenus dans cette analyse seront compareacutes aux preacutedictions desmodegraveles PYTHIA et PHOJET et aux reacutesultats disponibles dans ALICE agrave drsquoautres eacutenergies

Table of contents xi

Table of contents

1 Physics Motivations 111 Theoretical Baseline 1

111 Quantum ChromoDynamics (QCD) 3112 Chiral Symmetry 6113 Hadronic Matter mdash Quark-Gluon Plasma (QGP) 11

12 Heavy-Ion Physics Experimental Program 12121 Relevant Kinematic Variables 13122 Collision Geometry 14123 Evolution of a Heavy-Ion Collision 15124 Experimental Observables of the QGP 16125 Proton-Proton Collisions 22

13 Low-Mass Dimuon Measurements in ALICE 23

2 ALICE at the CERN LHC 2921 The Large Hadron Collider 29

211 The CERN accelerator complex 29212 The LHC schedule 30213 The Experimental Heavy-Ion Program 32

22 A Large Ion Collider Experiment (ALICE) 33221 The Central Barrel 34222 The Forward Detectors 36223 The Muon Spectrometer 38224 The ALICE software framework 40225 The ALICE Upgrade 41

3 Data Sample Selection and Integrated Luminosity Evaluation 4531 Data Sample Event and Track Selection 4532 Integrated Luminosity Evaluation 46

321 F inorm Calculation 47

322 The MB Trigger Cross Section 50323 Lint Evaluation 51

4 Monte Carlo Simulations 5341 Light-Meson Decays 53

411 Kinematical Distributions 54412 Dalitz Decays 54413 Two-Body Decays 57

42 Dimuons from Open Heavy-Flavor Decays 60421 PYTHIAndash FONLL Comparison 61422 Decay Chain Length in the Open Heavy-Flavor Processes 62

xii Table of contents

5 Signal Extraction 6551 Combinatorial Background Evaluation and Subtraction 65

511 The Event Mixing Technique 66512 Monte Carlo Validation of the Event Mixing Technique 67513 The Combinatorial Background Estimation 68

52 Invariant Mass Fit Procedure 70521 Specific Constraints on the Hadronic Cocktail Components 71522 Correlated Continuum Treatment 72523 A Few Examples of Hadronic Cocktail Fits 76

6 Systematics Evaluation 7961 Systematics on the Signal Extraction 80

611 Relative Branching Ratio of two-body and Dalitz Decays for the ηand ω Mesons 80

612 σηprimeσφ Cross-Section Ratio 80613 σρσω Cross-Section Ratio 81614 Upper limit of the fit 81615 The correlated continuum shape 81616 Systematic Uncertainty Computation 82

62 Systematics from the MC input 8263 Systematics on Trigger Efficiency 83

631 Evaluation of the Trigger Response Function 83632 Results 84

64 Systematics on Tracking Efficiency 85641 Preliminary Check 85642 Tracking Efficiency Evaluation 86643 MC parametrization 88644 Results 89

65 Summary of Systematic Uncertainty 89

7 Light Neutral Meson Production 9171 Estimation of the Number of Generated Mesons 91

711 The Two-Body Decay Case 91712 The Dalitz Decay Case 92

72 Cross-Section Production for Light Neutral Mesons 93721 Double-Differential η Meson Production 93722 ρω Meson Production 94723 Double-Differential φ Meson Production 98

Conclusions 105

A List of Runs 107

B Raw-Background Comparison mdash figures 111

C Hadronic-Cocktail fits mdash figures 123

Table of contents xiii

Bibliography 135

Chapter 1

Physics Motivations

Summary11 Theoretical Baseline 1

111 Quantum ChromoDynamics (QCD) 3112 Chiral Symmetry 6113 Hadronic Matter mdash Quark-Gluon Plasma (QGP) 11

12 Heavy-Ion Physics Experimental Program 12121 Relevant Kinematic Variables 13122 Collision Geometry 14123 Evolution of a Heavy-Ion Collision 15124 Experimental Observables of the QGP 16125 Proton-Proton Collisions 22

13 Low-Mass Dimuon Measurements in ALICE 23

11 Theoretical BaselineThe theoretical framework underlying the subject of the present thesis is the StandardModel of particle physics (SM) The SM gathers the theories describing the electromag-netic weak and strong interactions as well as Higgs sector providing at the same timea classification of all the subatomic particles known in terms of matter constituents andgauge bosons see figure 11 It was developed throughout the latter half of the 20th cen-tury the current formulation having been finalized in the mid-1970s upon experimentalconfirmation of the existence of quarks Since then discoveries of the Wplusmn and Z0 bosons(1983) the top quark (1995) the tau neutrino (2000) and the Higgs boson (2012) havegiven further credence to the Standard Model [1]

Each elementary interaction in the SM is characterized by an interaction range anda set of gauge bosons carrying the interaction charge It should be noted that the SMdescribes the weak and electromagnetic interactions as two different aspects of a singleelectroweak interaction

bull The weak interaction has a very small range of the order of 10minus18 m and is medi-ated by the Z0W+ and Wminus bosons This interaction affects all known elementaryfermions

2 Chapter 1 Physics Motivations

bull The electromagnetic interaction is characterized by an infinite range and affectsany particle having a non-zero electric charge The associated gauge boson is thephoton

bull The strong interaction acts at small distances having a range of the order of 10minus15 mat this range the strong interaction dominates over the other elementary interac-tions The strong interaction is mediated by the exchange of massless gauge bosonscalled gluons that interact with quarks anti-quarks and other gluons via a chargecalled color charge The theoretical framework for the strong interaction is givenby the theory of Quantum Chromodynamics described in more details in the nextsection

12e neutrino

νe

minus1

12

510999 keV

electron

e

RGB23

12

22+06minus04 MeV

up

uRGB

minus13

12

47+05minus04 MeV

down

d

12micro neutrino

νmicro

minus1

12

105658 MeV

muon

micro

RGB23

12

127 plusmn 003 GeV

charm

cRGB

minus13

12

96+8minus4 MeV

strange

s

12τ neutrino

ντ

minus1

12

177686 plusmn 016 MeV

tau

τ

RGB23

12

160+5minus4 GeV

top

tRGB

minus13

12

418+004minus003 GeV

bottom

b

plusmn1

1

80385 plusmn 0015 GeV

Wplusmn1

911876 plusmn 00021 GeV

Z

1photon

γ

color

1gluon

g0

12509 plusmn 024 GeV

Higgs

Hst

rong

inte

ract

ion

elec

trom

agne

ticin

tera

ctio

n

weak

inte

ract

ion

6qu

arks

(+6

anti-

quar

ks)

6le

pton

s(+

6an

ti-le

pton

s)

12 fermions(+12 anti-fermions)

13 bosons

Matter Constituents Gauge BosonsGoldstone

bosons

1st 2nd 3rd generation

1

Figure 11 Standard Model of particle physics and the different families of matter

11 Theoretical Baseline 3

111 Quantum ChromoDynamics (QCD)The Quantum ChromoDynamics (QCD) is the theory describing the hadronic physicsphenomena in the framework of the SM For this reason QCD is needed to correctlydescribe and interpret the observations in experiments involving high-energy hadronicinteractions like ALICE at the LHC

The color charge of the QCD can have three different values (red green and blue) aswell as the corresponding anti-colors This determines a part of the mathematical struc-ture of QCD based on the special unitary group of degree 3 mdash the Lie group SU(Nc=3)cThe complete mathematical structure of QCD is based on the Lorentz group L = SO(1 3)for the space-time transformations (gluons are in the vector representation and quarksin the spinor one) a gauge symmetry SU(Nc = 3)c an approximate light flavor symme-try SU(Nf = 3)f (this symmetry is not relevant even approximately for the remaining3 heavy flavors) The introduction of a three-color charge allowed at the beginning ofthe development of the QCD for the reconciliation of the observation of the spin-3

2 ∆++

baryon composed of three up quarks in the same spin state with the Pauli exclusionprinciple

The QCD Lagrangian LQCD

In the Quantum Field Theory formalism of particle physics any theory can be expressedin terms of a Lagrangian The mathematical expression of the Lagrangian density ofQCD1 is

LQCD =flavorssumf

qc1f (ipartmicroγmicroδc1c2 minusmfδc1c2) qc2

f

+flavorssumf

qc1f gsA

amicrotac1c2γ

microqc2f minus

14G

microνa G

amicroν + LCP

(11)

(Besides the explicit flavor summation each index when repeated twice indicates asummation on this index) In equation (11) micro ν are Minkowski indexes ranging from 0to 3 the qcf spinor represents the quark field of flavor f and color c (the Dirac index ofquark fields and γ-matrices are not written explicitly for convenience) mf is the massof a quark of flavor f gs is linked to the coupling constant of the theory αs = g2

s4π(after quantification and renormalization αs becomes a running coupling constant alsoquantification requires the introduction of ghost fields) the gluon fields Aamicro are Lorentzvectors Gmicroν

a is the gluon strength tensor and the ta matrices (generators of SU(Nc=3)c)are defined after the Gell-Mann matrices ta = λa2

The first term of LQCD

Lfree q =flavorssumf

qc1f (ipartmicroγmicroδc1c2 minusmfδc1c2) qc2

f = q (ipart minus mf ) q (12)

is a free Lagrangian representing the propagation of free quarks m representing thediagonal quark mass matrix

1 By language abuse the QCD Lagrangian density is simply named QCD Lagrangian

4 Chapter 1 Physics Motivations

The second term

Lint =flavorssumf

qc1f gsA

amicrotac1c2γ

microqc2f = gsqAq (13)

encodes the minimal (or Yukawa) coupling describing the interaction of the quark fieldswith the gluons

The third term of LQCD involvesGamicroν the gluon strength tensor which can be expressed

asGamicroν = partmicroA

aν minus partνAamicro + gsf

abcAbmicroAcν (14)

The fabc coefficients are the structure constants of SU(3) The first part of the tensor inequation (14) partmicroAaν minus partνA

amicro describes the gluon kinematics in analogy to the kinematics

description of photons in quantum electrodynamics (QED) The last term gsfabcAbmicroA

cν is

specific to QCD and describes the gluon auto-coupling due to the fact the QCD is anon-Abelian theory

The last term in equation (11) LCP is related to a possible violation of the CP-symmetry (due to a breaking of T symmetry and the conservation of the CPT symmetry)in the QCD sector This term is defined as

LCP = θg2s

32π2 GamicroνG

microνa (15)

where G is the dual of GGamicroν = 1

2εmicroναβGαβa (16)

and εmicroναβ is the antisymmetric Levi-Civita pseudo-tensor The θ parameter which wouldtake a non-zero value in case of CP-violation of LQCD can be experimentally accessed bymeasuring the electric dipole momentum of the neutron Its value compatible with zerois currently not explained by the theory [2 3]

The QCD Running Coupling Constant αs

By using the perturbative-QCD (pQCD) and the renormalization group equation [4] it ispossible to extract a running coupling constant αs depending on the momentum transferQ and on a parameter ΛQCD establishing the scale at which the perturbatively-definedcoupling would diverge At first order of perturbation theory αs can be expressed as

αs(Q2) = 12π

(11Nc minus 2Nf ) ln(

Q2

Λ2QCD

) (17)

where Nc is the number of colors (3) Nf is the number of light flavors respecting mq Q

and ΛQCD asymp 200 MeVFigure 12 shows the excellent agreement between available measurements of αs(Q2)

and the pQCD theoretical prediction beyond first order According to the value of thetransfer momentum Q two regimes of QCD can be defined for values of the transfermomentum Q above Q asymp 1 GeV (of the order of the nucleon mass) implying Q ΛQCD(or for distances well below 1 fm corresponding to the nucleon size) QCD is in the regime ofasymptotic freedom for Q 1 GeV QCD behavior is dominated by the color confinementmechanism

11 Theoretical Baseline 5

Figure 12 Summary of measurements of αs as a function of the momentum transfer Q and thepQCD prediction [4]

Asymptotic Freedom

In the large momentum transfer region Q ΛQCD or at small distance the decreasingof the coupling constant αs reflects the fact that the particles interacting over shortdistances 1 fm (the typical size of the nucleon) can be treated asymptotically as quasi-free particles This allows one to use a perturbative approach in performing calculationsbased on series of αs powers Let us notice that asymptotic freedom does not mean thatquarks are not interacting at all in high-energy collisions (the freedom is only asymptotic)Indeed it has been shown that at RHIC energy a strongly interacting QGP (s-QGP) iscreated

Color Confinement

Figure 13 Sketch of twoquark separation

In the small momentum transfer region or large distancethe coupling constant perturbatively diverges The physicalinterpretation for this phenomenon is the color confinementA schematic explanation of this phenomenon is the followingif it was possible to hold two color charges (for example twoquarks) and pull them part the energy density would con-centrate into a flux tube due to the non-Abelian characteris-tics of QCD (differently to QED) The energy would increasewith the separation until it reaches a threshold above whichpair creation is possible Figure 13 sketches this effect known as string breaking This isthe reason why in vacuum it is not possible to observe directly one isolated quark and allof them are found in composite particles named hadrons the color charge of hadrons iszero (hadrons are ldquocolorlessrdquo or ldquowhiterdquo) as the colored flux tube wraps within the hadronitself and can be observed

6 Chapter 1 Physics Motivations

A simple modelisation of the potential V (r) between two quarks is given by the Cornellpotential [5]

V (r) = minusαsr

+ σr (18)

In equation (18) the first term models the asymptotic freedom with a Coulomb potential(this term is dominating at r rarr 0) and the second term (dominating when r rarr infin) iscalled the string potential with the string tension σ sim (260 MeV2)

Hadrons can be classified as

bull mesons composed of one quark and one anti-quark

bull baryons composed of three quarks

bull exotic states like the recently observed tetra-quark etc

112 Chiral SymmetryThe chiral symmetry is one of the two fundamental symmetries of QCD governing low-energy QCD (low-hadronic masses) and the properties of the transition between the par-tonic and the hadronic phases observed in heavy-ion collisions

The chiral symmetry can be conveniently introduced and discussed considering theway Lorentz transformations act on bosons and fermions To start this discussion let usconsider a massless universe To understand the properties of the Lorentz transformationof any quantum state one can decompose it into its fundamental building blocks calledchiral fermions χR (the right chiral fermion) and χL (the left chiral fermion) PhysicallyχR and χL are spinor fields (spin frac12) and the R and L indices denote the helicities ofthe states In a massless universe the helicity is a good quantum number there is noLorentz transformation that can change the ldquoorientationrdquo of the spin hence for any inertialobservers the measured helicity would be the same Since χR and χL are fundamentalstates when Lorentz transformations are considered one can build any spin state bymixing these building blocks mathematically the Lorentz group can then be describedas a SU(2)RotimesSU(2)L group whose fundamental representations2 are χR and χL

Let us now consider a massive fermion state obviously now two observers with differ-ent speed relative to the fermion will measure different projections of the spin along themomentum of the particle the helicity is no more a good quantum number The chiralfermions χR and χL can now transform into one another this mechanism is called thebreaking of the chiral symmetry As anticipated in the introduction of this section thissymmetry is crucial to understand the low-mass sector of QCD since it is dominated byhadronic states composed of almost massless quarks (namely u d s composing the light

2 To see why the SO(13) Lorentz group L can be described by the combination of two SU(2) groupsone has to remember that L contains three rotations (that gives one SU(2) group) and three boosts (thatcan be seen as rotation involving the time direction and an imaginary angle that gives another SU(2)group) Those two algebras are not independent (eg boost and rotation do not commute) but they canbe decoupled into SU(2)RotimesSU(2)L independent algebras

11 Theoretical Baseline 7

neutral meson studied in this thesis) compared to the typical scale of QCD ΛQCD (seetable 11)

u m = 22+06minus04 MeVc2 c m = 127plusmn 003 GeVc2 t m = 160+5

minus4 GeVc2

d m = 47+05minus04 MeVc2 s m = 96+6

minus4 MeVc2 b m = 418+04minus03 GeVc2

Table 11 Quark masses [4]

In the following we will explain with a very simple quark model some observablephenomena linked to the fundamental QCD chiral symmetry the non observation ofdegeneration in mass between the scalar and pseudo-scalar octet as well as the spontaneouschiral symmetry breaking related to the phase transition observed eg in LHC arounda temperature of 170 MeV

a A Lagrangian for a free massless quark

For one chiral quark χR the free Lagrangian is3

Lfree qR = iχdaggerRpart0χR + iχdaggerRminusrarrσ middotminusrarrpart χR (19)

the form of the Lagrangian being dictated by the usual constraints (Lorentz invariancehermiticity conservation laws) but for one quark flavor the state with opposite helicityalso exists in nature for one quark flavor one can write Lfree q = Lfree qR + Lfree qLThis can be conveniently written

Lfree q = qipartq (110)

where q is a Weyl spinor (4 component spinor)

q =[χRχL

] (111)

and the usual notation q = qdaggerγ0 (see chapter 32 of [1])

b Explicit breaking of the chiral symmetry in presence of a mass term

The Lagrangian of a free quark of mass m is

Lfree q = q (ipart minusm) q = L0 + Lm (112)

This Lagrangian contains a mass term which is explicitly written as

Lm = mqq = m(χdaggerRχL + χdaggerLχR

) (113)

The number of R (L) quarks in this system is given by

NRL = χdaggerRχR(χdaggerLχL

) (114)

3 We do not consider Majorana fermions in this manuscript

8 Chapter 1 Physics Motivations

Let us define a transformation belonging to the symmetry group U(1)RotimesU(1)L

χR rarr eiθR χR

χL rarr eiθL χL

Lfree q rarr L0 +m(ei(θLminusθR) χdaggerRχL + ei(θRminusθL) χdaggerLχR

) (115)

this symmetry is broken by the mass term as discuss previously when considering thecase of the boost of a massive fermion the number of R or L quarks is not the samefor all observers However this symmetry restricted to the case of θR = θL equiv θV is notbroken and is associated to the conservation of the fermion number This result in theUV (1) symmetry

q rarr eiθV q lArrrArr[χRχL

]rarr eiθV

[χRχL

] Lfree q rarr Lfree q (116)

The V stands for Vector (it is the conservation of the so-called vector current V micro = qγmicroq)For further convenience we also define UA(1) as the symmetry group with transformationgiven by θR = minusθL equiv θA the A stands for Axial (a transformation in UA(1) is thus givenby q rarr eiθAγ5 q)

c For more than one flavor

Finally let us consider the Lagrangian of a system composed by the two lightest flavorsu and d giving Nf = 2 (but this discussion could also be extended to a system includinga third flavor s light enough compared to ΛQCD)

Lfree light q = iqupartmicroγmicroqu + iqdpartmicroγ

microqd minusmuququ minusmdqdqd (117)

In this case one can introduce for convenience the iso-spinor ψ =(quqd

)

Lfree light q = ψ (ipart minus m0)ψ (118)

= iψpartmicroγmicroψ minus mu +md

2 ψψ minus mu minusmd

2 ψτ3ψ (119)

where m0 is the quark masses matrix τ3 is the iso-spin Pauli matrix (noted τ not toconfuse it with σ3 that acts on spinor index) For convenience let us also use

ψR equiv[quRqdR

]equiv

quR0qdR0

equiv PRψ (120)

wherePR = 1 + γ5

2 (121)

and the same for ψL wherePL = 1minus γ5

2 (122)

11 Theoretical Baseline 9

The symmetry we discussed in paragraph b is extended by adding a mixing ofthe flavor states This is what is usually called in the literature ldquochiral symmetryrdquoSUR(Nf )timesSUL(Nf )

The iso-spinor ψ = ψR + ψL transforms under the chiral symmetry as

ψ rarr eiminusrarrθR middotminusrarrt ψR + ei

minusrarrθL middotminusrarrt ψL (123)

where minusrarrt = ~τ

2 and minusrarrθRminusrarrθL isin (R3)2

As in the one flavor case the kinetic term

Lk = iψLpartmicroγmicroψL + iψRpartmicroγ

microψR (124)

is chiral invariant while the mass term is not However when the mass difference is zero(the so-called exact isospin limit) the SUV (Nf ) symmetry is exact

d The symmetry of the quark sector of QCD mdash the eightfold way

Let us consider only massless quarks (a good approximation for u d and s) giving Nf = 3and the light sector only

LQCD = Lfree light q + Lr (125)

where Lr incorporates the terms appearing in the second line of equation (11) as wellas any term relative to heavy quark Lr transforms trivially or in the same way as aLfree light q For this reason the chiral transformation of LQCD can be studied consideringLfree q only In this massless scenario the largest symmetry group for LQCD can be ex-pressed as G=UR(1)otimesUL(1)otimesSUR(Nf )otimesSUL(Nf ) = UR(Nf )otimesUL(Nf ) A transformationof this group is given by

ψ rarr eiθR t ψR + eiθL t ψL (126)

where t =(1~t

)and θ =

(θ ~θ

) This symmetry would allow one to classify light hadronic

states into double U(Nf = 3) multiplets (one for left-handed and one for right-handed)where scalar and pseudo-scalar members would be invariant under U(Nf = 3) rotationin the flavor space which implies the same mass This is not what is observed Atmost one sees multiplets (approximately) invariant under vector symmetry SUV (Nf = 3)rotation (see paragraph b ) for example the octet of pseudo-scalar mesons π K η andthe decuplet of baryons n p Λ etc

The chiral partner of the cited pseudoscalar meson octet is the scalar octet of the a0κ and σ meson the fact that no degeneracy in mass is observed between the members ofthe pseudoscalar octet and the members of the scalar one is linked to the G symmetrybreaking For convenience one can rewrite G = UR(Nf = 3)timesUL(Nf = 3) as

G = UV (1)otimes UA(1)otimes SUV (3)otimes SUA(3) (127)

where

bull UV (1) is the symmetry already discussed in paragraph b it is the conservation ofthe individual flavor quark number

10 Chapter 1 Physics Motivations

bull UA(1) was also introduced in paragraph b This group should be a symmetry in themassless scenario leading to the observation of mη = mηprime (one should see a nonetinstead of an octet of degenerated pseudoscalar mesons) [6] This is howevernot the case The more generally accepted explanation is that the gluon part Lr

of LQCD generates an explicit breaking of the UA(1) symmetry due to non-zeroquantum fluctuations in the gluon strength tensor sim 〈G2〉

G2 = GmicroνGmicroν (128)

bull SUV (3) this is the observed (approximate) symmetry between the masses of themembers of a multiplet4 This means that the SUV (3) symmetry is good enough toclassify hadronic states this corresponds to ldquothe eightfold wayrdquo

bull SUA(3) this group should be again a symmetry in a massless scenario one wouldthen observe a degeneracy between the scalar and the pseudoscalar meson octetThis is not the case because the chiral symmetry SUV (Nf )otimesSUA(Nf ) is sponta-neously broken (Goldstone mechanism) to SUV (Nf = 3) The π K η are the(almost) massless Goldstone bosons of this mechanism

e Spontaneous breaking of the chiral symmetry and phase transition

The Goldstone mechanism just mentioned when discussing the SUA(3) group can beunderstood in the framework of a quark model the Nambu-Jona-Lasinio model [78] withmassless quarks For two light flavors one has

LNJL = ψ (ipart)ψ +Gs

[(ψψ

)2+(ψiγ5~τψ

)2] (129)

where Gs is a coupling constant for four-quark contact interactions It mimics the shortrange strong interaction as a contact interaction This Lagrangian is chirally invariantsince the interaction term is built from a scalar ψψ and its pseudoscalar counterpart soas to be invariant

If the interaction term is sufficiently large (GsΛQCD2 sim 1) quarks can condense

(〈ψψ〉 6= 0) and equation (129) can be rewritten as

LNJL ψ(ipart + 2Gs〈ψψ〉

)ψ + middot middot middot (130)

The quantity mD equiv minus2Gs〈ψψ〉 acts exactly as a mass term (it is the so-called dynamicalmass) and spontaneously breaks the chiral symmetry

If temperature increases generally there will be a screening of the interaction and〈ψψ〉(T ) = 0 for T gt Tc where Tc is called the phase transition temperature the chiralsymmetry is said to be restored At approximately the same temperature the decon-finement occurs hence the high temperature phase is also known as the Quark GluonPlasma (or QGP) phase The fact that chiral symmetry restoration and deconfinementare occurring at almost the same temperature happens because in low-energy QCD thereis basically one scale only ΛQCD

4 The observed mass differences are not exactly zero because the u d s mass differences are notexactly zero (isospin limit)

11 Theoretical Baseline 11

minusrarrπσ

Ueff

A

B

a

minusrarrπσ

Ueff

b

minusrarrπσ

Ueff

c

1Figure 14 Effective potential as a function of ~πndashσ left to right going towards fully chirality restora-tion

If one takes σ sim ψψ and ~π sim ψiγ5~τψ the chiral symmetry restoration can be describedin the same way as the Goldstone mechanism related to the Higgs mechanism At lowtemperature one has a Goldstone effective potential Ueff (see figure 14 a) that has the well-known Mexican hat shape the ldquovacuumrdquo (relative to the expectation value 〈~π〉 = 0 = 〈σ〉)is in fact unstable The physical vacuum is located at the bottom of the potential on theso-called chiral circle As the temperature increases the chiral circle shrinks until the state〈~π〉 = 0 = 〈σ〉 is stable (see figure 14 c) this is the restoration of the chiral symmetry

The chiral symmetry restoration has an impact on the in-medium spectral functionsof hadrons the most easily accessible experimental observable related to this mechanismis the ρ meson thanks to its short life-time (13 fmc) allowing it to be produced anddecay inside the volume of the QGP typically obtainable in heavy-ion collisions

113 Hadronic Matter mdash Quark-Gluon Plasma (QGP)

As already remarked low-energy QCD mechanisms are driven by the same scale param-eter ΛQCD this is the reason why chiral symmetry restoration and color deconfinementhappen under the same thermodynamical conditions identifiable in the QCD phase dia-gram shown in figure 15

This schematic diagram presents two main regions The first one is the region atlow temperature and density where quarks and gluons are confined inside hadrons andthe chiral symmetry is broken The second region is characterized by large values oftemperature and or net baryon density where the relevant degrees of freedom are quarkand gluon and is a new state of matter the Quark Gluon Plasma (QGP) These tworegions are separated by a phase transition At vanishing net baryonic density (from 0 toan hypothetical critical point) this frontier is a smooth phase (ldquocross-overrdquo) transitionAt increasing value of net baryonic density beyond an hypothetical critical point thefrontier becomes a first order phase transition At extreme values of the net baryonicdensity and low temperature other hadron phases of the hadronic matter can be possibleas the hypothetic color superconducting phase proposed by some theoretical speculations

The only way to get experimental access to the QCD phase diagram in the regionof deconfinement under controlled conditions is to perform ultra-relativistic heavy-ioncollisions Different regions of the phase diagram can be covered by changing the center-

12 Chapter 1 Physics Motivations

Figure 15 Schematic QCD phase diagram as a function of temperature and net baryon density

of-mass energy of the collision as the energy increases the initial temperature of thesystem increases and its net baryonic density decreases At the high-energy frontier theexperiments carried at the Large Hadron Collider (LHC) at CERN and the RelativisticHeavy-Ion Collider (RHIC) at the BNL are suited to reproduce the conditions of hightemperature and low-net baryonic density present in the early Universe

In this QCD phase diagram there is a hypothetical Critical Point and this pointprovides a major research focus both theoretically and experimentally On the theory sidelattice QCD (LQCD) gives accurate results only at zero density It can be extrapolatedat finite density Another technique is the use of effective models as the NJL one [7] Onthe experimental side studies of heavy-ion collisions are done with several energies andion species (NA61 STAR PHENIX) and they probe different density regimes Finallycompact star observation may also give results about the zero temperature high densityphase of QCD

12 Heavy-Ion Physics Experimental ProgramThe experimental study of QGP needs this state of matter to be recreated in laboratoryAs we have seen in the previous section high density andor temperature are needed inorder to reach the conditions for the creation of the QGP state these conditions are metin ultra-relativistic heavy-ion collisions This experimental tool allows one to change theenergy density of the system by varying the size and the energy of the colliding nuclei

12 Heavy-Ion Physics Experimental Program 13

Several probes of the QGP exist which will be described later in this chapter the design ofa heavy-ion detector directly depends on the probes chosen for the experimental program

The relativistic heavy-ion experimental program started in the early 1980s at the BNLAGS [9] and CERN SPS [10] (collision energy per nucleon pair up to radicsNN asymp 20 GeV)and continues today both at the SPS and at the RHIC [11] and LHC [12] colliders whereenergies up to radicsNN = 02 TeV and 5 TeV are reached respectively

121 Relevant Kinematic Variables

Before discussing collision geometry and QGP probes we briefly introduced the mainkinematic variables of interest for heavy-ion physics and particularly for the study pre-sented in this manuscript

Transverse Momentum (pT) The kinematics of a particle can be described by anenergy-momentum quadrivector In the context of a high-energy experiment where aprivileged axis is defined by the beams the 3-momentum can be conveniently decomposedinto its longitudinal (pz) and transverse (pT) components The transverse momentum isinteresting for two reasons firstly the transverse degree of freedom is created during thecollision since the initial state is characterized only by the longitudinal degree of freedomof the colliding particles secondly the transverse momentum is invariant under Lorentzboosts along the z-axis allowing one to directly compare the pT distributions measuredin fixed-target and collider experiments

Rapidity (y) The longitudinal degree of freedom of a particle kinematics can be con-veniently expressed in terms of the rapidity variable y defined as

y = 12 ln

(E + pzcE minus pzc

) (131)

It can be shown that the rapidity is additive under Lorentz boosts along the z-axisthis allows one to directly compare the shape of the rapidity distributions measured infixed-target and collider experiments

Pseudo-Rapidity (η) In the ultra-relativistic regime where p m and E asymp p therapidity can be approximated by the pseudo-rapidity η

y = 12 ln

(E + cp cos θE minus cp cos θ

)asymp 1

2 ln(

1 + cos θ1minus cos θ

)= minus ln

[tan

(θ

2

)]equiv η (132)

The pseudo-rapidity is especially useful whenever the energy and the longitudinal mo-mentum pz are not available at the same time in this case the pseudo-rapidity providesan approximation of the rapidity based on the measurement of the polar angle θ only (theangle between the z-axis and the particle direction)

14 Chapter 1 Physics Motivations

Invariant Mass In case the particle of interest for a given analysis is not directlyobservable (because of its short life time) its kinematics can still be reconstructed byidentifying and measuring its decay products the quadrivectors of the daughters canbe composed to obtain the quadrivector of the mother particle from which can be easilyobtained its invariant massm2c4 = E2minusp2c2 In the specific case of the analysis presentedin this thesis the φ meson (as well as the other low-mass neutral mesons η ρ ω) hasbeen identified through its decay into two muons

122 Collision GeometryTo clearly interpret the observables in a heavy-ion collision one also needs to characterizeits geometry The two main geometric parameters characterizing a heavy-ion collision arethe centrality and the event plane

Centrality mdash The centrality is a concept related to the finite size of the collidingnuclei in fact heavy nuclei (like the lead nuclei accelerated at the LHC) can be regardedas extended objects consisting of several nucleons Some of these nucleons participate tothe collision and are called participants while the remnants do not interact and are calledspectators see figure 16-left

x

y

ΦRP

Figure 16 Schematic representation of a lead-lead collision

As it can be also seen in figure 16-left an impact parameter b can be identified whenlooking at a nucleus-nucleus collision in the transverse plane If this parameter is nullthe overlap between the two nuclei and the energy available in the overlapping volumeis maximal these collisions are classified as most central For larger impact parametersthe overlap region between the two nuclei and the energy available in the overlappingvolume become smaller these collisions are classified as semi-central semi-peripheral andperipheral for increasing values of b If the impact parameter is larger then two nuclearradii the collision is called ultra-peripheral and there is no hadronic interaction betweenthe two nuclei

The impact parameter in a heavy-ion collision is not directly measurable due to itsfemtoscopic size Yet b (so the centrality of the collision) can be estimated by quantifyingthe produced particle multiplicity since the two quantities are strongly correlated [13]An effective way to establish this correlation is provided by the Glauber Model [14]

In smaller collision systems like pp and p-Pb the measurement of the produced parti-cle multiplicity is still possible giving insight into the energy of the partonic interactions

12 Heavy-Ion Physics Experimental Program 15

involved in the collision (the so-called ldquoevent activityrdquo) However due to the loose corre-lation between this quantity and the geometry of the collision in such small systems [13]no geometrical interpretation can be established in this case

Event plane mdash In case the collision is not head-on it is possible to define the eventplane as a plane formed by the beam direction and the impact parameter The transverseprofile of this plane in non-central nucleus-nucleus collisions is represented in the rightpanel of figure 16 The determination of the event plane orientation event-by-event isimportant to characterize the azimuthal anisotropies observed in the measurement of theparticles produced in the collisions

123 Evolution of a Heavy-Ion CollisionFigure 17 illustrates the evolution of the hadronic collision in the two cases where theQGP is created (right side) or not (left side)

Figure 17 Space time evolution left-side without QGP right-side with QGP

Collisions with creation of QGP mdash In this case a dense and hot system of freepartons is created in the collision the typical size of the system is such that a ther-modynamical approach can be adopted and a medium temperature defined This sys-tem of deconfined quarks and gluons undergoes multiple interactions and the expansioncharacterized by a hydrodynamic-like collective expansion During this expansion thehadronization starts and there is a cooling of the system until the critical temperatureof the transition between the partonic and hadronic phases (Tc) is reached The coolingcontinues the medium is a hadronic gas until the temperature of chemical freeze-out(Tch) is reached (from above) beyond this point the inelastic interactions stop and the

16 Chapter 1 Physics Motivations

composition of hadronic species is fixed The cooling continues until the kinetic freeze-outis reached beyond this point the elastic interactions also stop and the hadrons fly to thedetectors with kinematic distributions characterized by a temperature Th

Collisions without creation of QGP mdash In this case the collision starts by a pre-equilibrium partonic phase which directly leads to the hadronic phase without passingthrough any significant hydrodynamic or thermodynamic evolution After the elasticinteractions between the hadrons stop the species and their kinematics are fixed

124 Experimental Observables of the QGPA variety of observables exists giving insight into the properties of the QGP each ob-servable providing a complementary piece of information

Bulk physics light-flavor radiation

Figure 18 Hadron yields from ALICE at theLHC and fit with the statistical hadronizationmodel [15]

The bulk radiation is mainly composed oflight-flavored hadrons (u d s quarks) Hav-ing a typical scale of 1 fm 1(200 MeV)these hadrons cannot exist inside the decon-fined medium For this reason the light-flavor radiation measured by the detector isformed at the transition between the QGPand the physical vacuum taking place at thecritical temperature Tc 160minus 180 MeVThis fact is confirmed by the good agreementbetween the measured relative abundancesof the main light hadron species (includinglight hypernuclei) and the prediction of a sta-tistical hadronization model with fixed ther-modynamical parameters at the transitionphase see figure 18

The global hydrodynamical flow drivingthe expansion of the deconfined medium in-

duces the radial flow characterizing the light-flavor radiation pT spectrum Experimen-tally it is possible to observe this radial flow by measuring the pT dependence of the yieldfor the various species of the bulk radiation an example is given in figure 19

Moreover if the initial conditions are not spherically symmetric as it is in fact the casein non-central heavy-ion collisions the difference in pressure in different spatial directionswill lead to a further ldquodirectedrdquo or ldquoellipticrdquo flow (characterized by the v2 parametersin the Fourier expansion of the azimuthal particle distribution) Since the elliptic flowdepends on the initial conditions of the expending medium (like the geometry and theshear viscosity) the flow studies of hadron spectra can provide information about theearlier pre-hadronic stages of the collisions For example figure 110 illustrates how the

12 Heavy-Ion Physics Experimental Program 17

Figure 19 Transverse momentum distributionsof the sum of positive and negative particles asmeasured by ALICE fitted individually with ablast wave function compared to RHIC dataand hydrodynamic models [16]

Figure 110 Elliptic flow coefficient of chargedparticle in PbndashPb collisions as a function of cen-trality compared to viscous hydrodynamic re-sults [1718]

shear viscosity (ηs) of the medium can be estimated by the analysis of the centralitydependence of the v2 parameter

Strangeness productionWithin the light-flavor radiation strangeness production plays a peculiar role since thereare no strange valence quarks in the initial state of the collision as opposed to u and dquarks yet they are sufficiently light to be abundantly created in the course of the colli-sions High-pT strangeness production happens either at the early stages of high-energycollisions in hard partonic scattering processes by flavor creation and flavor excitation(see Feynman diagrams in figure 111) or during the subsequent partonic evolution viagluon splittings Low-pT strangeness production is dominated by non-perturbative pro-cesses like string fragmentation however due to the heavier mass of the strange quark(95plusmn 5 MeVc2) than the u and d quarks the production of strange hadrons in fragmen-tation processes is suppressed in comparison to the production of hadrons containing onlyu and d quarks

q

q s

s g

g s

s

g

g s

s g

g s

s

Figure 111 Feynman diagrams in pQCD at first order for the strangeness production inside QGP

18 Chapter 1 Physics Motivations

Figure 112 pT-integrated yield ratios of strange and multi-strange hadrons to (π+ + πminus) as afunction of 〈dNchdη〉 measured in the rapidity interval |y| lt 05 [20]

An enhancement of strange hadron production was historically proposed [19] as anindication of the QGP formation the argument is that strangeness production would beenhanced by the large energy density available in the medium the enhancement scal-ing with the strangeness content of each hadron Figure 112 shows the ratio of strangehadrons over pions as a function of event multiplicity for pp p-Pb and Pb-Pb collisionsIn this figure one can appreciate the difference of the measured enhancement for strangehadrons containing different numbers of strange quarks Ks mesons and Λ baryons con-taining one strange quark Ξ baryons containing two strange quarks and Ω baryonscontaining three strange quarks

JetsIn high-energy collisions a significant production of hard partons is observed thehadronization of these partons produces a narrow cone of hadrons and other particlescorrelated together named jet In heavy-ion collisions jet measurements offer the pos-sibility to probe the deconfined medium by measuring the energy loss of the initial hardparton (jet quenching) and the modification of the jet cone structure and composition(jet broadening) Due to the high energy involved in the production of hard partons jetphysics in heavy-ion collision basically started at RHIC in 2000rsquo whereradicsNN values of theorder of 100 GeV became available for the first time Today jet physics in heavy-ion col-lisions profits from the larger energies available at the LHC implying larger cross-sectionsfor hard scattered partons and an extended range of jet energies

In figure 113 and 114 two examples of jet physics results in heavy-ion collisions are

12 Heavy-Ion Physics Experimental Program 19

Figure 113 The b-tagged jet RAA as a functionof Npart for two jet pT selections in Pb-Pb atradicsNN = 276 TeV in CMS [21]

(GeVc)Tassoc

p1 15 2 25 3 35 4 45

)shyπ

++

π)

(p

(p+

0

02

04

06

08

1

12

1415)plusmn lt η∆06 lt plusmn lt 052 φ∆Bulk Ratio (shy052 lt

lt 04)η∆ lt 052 shy04 lt φ∆Peak shy Bulk Ratio (shy052 lt

Pythia (Peak shy Bulk Ratio)

= 276TeV 0shy10 centralNN

sPbshyPb

lt 100 GeVcTtrig

50 lt p

ALIminusPRELminus15474

Figure 114 Ratio of proton to pion spectraas function of pT for the ldquobulkrdquo and ldquopeak-bulkrdquo [22]

shown In figure 113 the nuclear modification factor (RAA) of b-tagged jets is shown as afunction of Npart as measured by the CMS experiment at the LHC in Pb-Pb collisions atradicsNN = 276 TeV A clear decreasing trend for RAA is observed for increasing values of

Npart interpreted as a manifestation of the jet-quenching mechanism In figure 114 theproton-over-pion ratios in the bulk and in jet are shown as a function of pT measuredby ALICE in Pb-Pb collisions at radicsNN = 276 TeV The comparison of the measuredproton-over-pion ratio in jets (ldquopeak-bulkrdquo) with the prediction from PYTHIA suggeststhat no significant medium-induced modification of particle ratios is at play in jets

Heavy flavorsThe abundant production of c and b quarks at LHC offers a unique possibility to un-derstand the details of the energy loss thermalization and hadronization mechanismscharacterizing the interaction of heavy quarks with the medium

The energy loss can be studied through the measurement of the pT-dependence of thenuclear modification factor RAA for the various heavy flavor hadron species In figures 115and 116 the RAA averaged over the main non-strange D-meson species is compared withthe RAA of light-flavored mesons and (non-prompt) Jψ from B decays respectivelyprobing the suppression hierarchy RB

AA gt RDAA amp Rlight quarks

AA reflecting the different energyloss of light charm and beauty quarks Despite the large uncertainties the data suggesta similar energy loss for the charm and light quark a scenario also supported by sometheoretical models [23] The heavy quark hadronization mechanism in the medium can bestudied by comparing the production of various species of heavy flavor hadrons [2425]

QuarkoniaQuarkonia are resonance states of charm-anticharm (charmonia) or bottom-antibottom(bottomonia) pairs Quarkonium measurements provide information on the properties of

20 Chapter 1 Physics Motivations

Figure 115 Prompt D-meson RAA as a func-tion of pT compared to the pion and charged par-ticles RAA in the 0-10 centrality classes [26]

rangpart

Nlang0 50 100 150 200 250 300 350 400

AA

R

0

02

04

06

08

1

12

14

(empty) filled boxes (un)correlated syst uncertψ() 50shy100 for nonshyprompt J

|lt05y |clt16 GeVT

pD mesons (ALICE) 8lt

= 276 TeVNNsPbshyPb

rangpart

Nlang shifted by +10 in plusmnπ

(CMS)ψ Nonshyprompt J|lt12y |clt30 GeV

Tp 65lt EPJC 77 (2017) 252

50shy80

40shy5030shy40

20shy3010shy20

0shy10

|lt08y |clt16 GeVT

p (ALICE) 8ltplusmnπ

ALIminusPUBminus129313

Figure 116 Comparison of the average D-meson RAA in 8ltpT lt16 GeVc with chargedpions in the same pT range and Jψ from Bdecays in 65ltpT lt30 GeVc [27]

the medium in the early stages of heavy-ion collisions being sensitive to the in-mediumdissociation and recombination mechanisms for the various quarkonium states Quarko-nium dissociation was indeed proposed as a signature of the production of QGP in heavy-ion collisions due to a color-screening effect [28 29] in analogy to the Debye-screeningin electrostatics coupled to a dynamical interaction of the heavy-quark pair with thesurrounding partons [3031]

Figure 117 Dimuon mass spectrum in the Υregion in Pb-Pb collisions at radicsNN = 502 TeVwith CMS experiment [32]

rangpart

Nlang0 50 100 150 200 250 300 350 400

AA

R

0

02

04

06

08

1

12

14-micro+micro rarr ψInclusive J

c lt 8 GeVT

p lt 4 y = 502 TeV 25 lt NN

sPb minusALICE Pb

c lt 8 GeVT

p lt 4 y = 276 TeV 25 lt NN

sPb minusALICE Pb

c gt 0 GeVT

p| lt 22 y = 02 TeV 12 lt |NN

sAu minusPHENIX Au

ALI-DER-112313

Figure 118 The participant number depen-dence of RAA for inclusive Jψ in ALICE in Pb-Pb collisions at radicsNN = 502 and 276 TeVand in PHENIX at forward rapidity in Au-Au atradicsNN = 200 GeV

12 Heavy-Ion Physics Experimental Program 21

The dissociation mechanism resulting in the suppression of the less bound quarkoniumstates is best illustrated in figure 117 showing the dimuon mass spectrum in the Υ regionmeasured by the CMS experiment with the Pb-Pb data at radicsNN = 502 TeV comparedto the expected yield in pp One can observe that the suppression of the Υ(3S) state isstronger than the one of the Υ(2S) with respect to the Υ(1S) due to the different bindingenergy of the two resonance states (sequential melting of quarkonium)

For the charmonium states a statistical recombination mechanism is expected to com-pete with dissociation for sufficiently large values of the cc cross-section expected forinstance in Pb-Pb collisions at the LHC energies The interplay of the suppression andrecombination mechanisms has indeed been proposed to explain the ALICE data for thecentrality dependence of the Jψ RAA in Pb-Pb at radicsNN = 502 and 276 TeV shown infigure 118 together with the PHENIX results in Au-Au collisions at radicsNN = 200 GeVFor 〈Npart〉 gt 120 the ALICE Jψ RAA shows no significant centrality dependence and isalmost a factor of 3 larger than the PHENIX data for the most central points no sizablerecombination mechanism being at play at RHIC energy Further insight on the role ofstatistical recombination in charmonium production at the LHC could come from thecomparison of the Jψ elliptic flow measurements with the theoretical models

Electromagnetic probesElectromagnetic radiation (real photons and dileptons from virtual photons) is emittedfrom a variety of processes prompt photons from initial hard scatterings thermal photonsand medium-modified ρ dileptons from the QGP phase real and dileptons from radiativedecays after hadronization The fact that electromagnetic radiation is emitted during thewhole evolution of the collision represents at the same time an advantage (for instancethe possibility of probing the entire lifetime of the fireball) and a drawback (the variouscomponents being hard to disentangle) Another advantage of electromagnetic radiationis that whenever emitted it is not affected during its propagation by the strong inter-action dominating inside the deconfined medium providing a clean probe of hadronicinteractions

Figure 119 shows the pT spectrum of real photons in Pb-Pb collisions atradicsNN = 276 TeV measured by ALICE for three centrality classes In all centrality

classes no evidence for medium influence is observed at high pT At low pT (gt 2 GeVc)on the contrary an excess of real photons with respect to pQCD real photon productionis observed for mid- and central collisions with a temperature of Teff asymp 300 MeV ex-tracted in central collisions [33] This excess might be related indeed to the productionof thermal photons from the QGP phase

Figure 120 shows the excess in the dimuon mass spectrum with respect tothe expected hadronic sources measured by NA60 in semi-central In-In collisions atradicsNN = 173 GeV compared to various theoretical scenarios This excess is domi-

nated by the medium-modified ρ line shape at low mass (gt 1 GeVc2) and by a thermalcontribution at intermediate mass ( 1 GeVc2) and its study allows one to shed lighton the relevant properties of QGP equation of state [34 35]

22 Chapter 1 Physics Motivations

Figure 119 Direct photon spectra in PbndashPbcollisions atradicsNN = 276 TeV for three central-ity classes compared to model in pp collisions atthe same energy scaled by the number of binarynucleon collisions for each centrality class [33]

Figure 120 Dimuon invariant-mass in semi-central In-In collisions with NA60 [34]

125 Proton-Proton Collisions

Proton-proton collisions present various aspects of interest in the context of heavy-ionphysics namely as a reference for heavy-ion observations test for pQCD calculationsinput for phenomenological non-perturbative models and environment for collectivity insmall systems

As a reference for heavy-ion collisions pp measurements are needed in order hot andcold nuclear matter effects to be properly disentangled respectively in nucleus-nucleusand proton-nucleus collisions This implies two necessities collecting pp reference dataat the same radicsNN energy as more complex collision systems and finding appropriatevariables which could relate pp pA and AA observations A primary example is givenby the nuclear modification factor (RAA) defined as the direct ratio of production cross-sections in AA or pA over the corresponding pp reference scaled by the number of binarycollisions for example to study the charged-particle production [36]

Proton-proton collisions are also an ideal environment for the study of hard and softprocesses in vacuum In the first case (jets Jψ Υ ) one has the possibility to testpQCD calculations in the second case constraints on phenomenological models can bederived in terms of kinematic distributions and production cross-sections [3738]

Finally it is possible to use pp collisions for studying the emergence of collective ef-fects in small systems This study is typically performed analyzing the data in classes ofcharged particle multiplicity the onset of collectivity being driven by the event activityIn this context the observation of collective effects in large-activity pp and p-Pb colli-sions showing striking similarities with those observed in Pb-Pb collisions represents anintriguing challenge for theoretical models [39]

13 Low-Mass Dimuon Measurements in ALICE 23

13 Low-Mass Dimuon Measurements in ALICEThis thesis work is focused on low-mass dimuon measurements in pp collisions atradics = 13 TeV For this reason it is interesting to report here about low-mass dimuon re-

sults and currently ongoing analyses in the other collision systems and energies availableLow-mass dimuon production is studied in ALICE in Pb-Pb collisions atradicsNN = 276 and502 TeV in p-Pb collisions at radicsNN = 502 and 816 TeV as well as in pp collisions atradics = 276 502 7 and 8 TeV Due to the favorable position of its two-body decay in the

low-mass dimuon region with no significant competing sources beyond the smooth cor-related continuum from open heavy flavors the φ-meson has been the privileged subjectof the low-mass dimuon analyses in the first years of LHC operation

Pb-Pb collisionsThe LHC provided Pb-Pb collisions in Run 1 at radicsNN = 276 TeV and in Run 2 atradicsNN = 502 TeVDue to the limited statistics of the Run 1 data the φ-meson study is limited to the

pT range from 20 to 50 GeVc for the dimuons in Pb-Pb collisions at radicsNN = 276 TeVsee figure 121 where the lower limit is imposed by the hardware trigger condition onsingle muons (pT 1 GeVc) and the upper limit is defined by the available statisticsThe analysis of the Run 1 low-mass dimuon data allowed the measurement of the nu-clear modification factor RAA of the φ-meson at forward rapidity in Pb-Pb collisions atradicsNN = 276 TeV shown in figure 122 together with the corresponding ALICE mea-

surement at mid-rapidity and the PHENIX measurement at mid-rapidity in Au-Au andCu-Cu collisions at radicsNN = 200 GeV As can be seen from the comparison of the twoALICE sets of points the RAA does not exhibit any significant dependence on the rapidityregion considered on the contrary the PHENIX points seem systematically higher thanthe ALICE ones although still compatible with the latter within the total uncertaintiesAll the data sets agree on the general decreasing trend of RAA as a function of 〈Npart〉

The larger statistics available from the first Pb-Pb data taking at radicsNN = 502 TeVof Run 2 (2015 a second one being foreseen for 2018) allows the analysis of φ-mesonproduction to be performed up to 7 GeVc starting again from 2 GeVc due to thehardware trigger condition The pT dependence of the φ-meson yield could be studied inseveral centrality classes as shown in figure 123 where the data points are fitted withthe power-law function

dNdpTprop pT[

1 +(pTp0

)2]n (133)

where n and p0 are the free parameters of the fit The centrality dependence of φ-mesonproduction is also studied by looking at the central-to-peripheral ratio RAA as a functionof 〈Npart〉 as shown in figure 124 this dependence suggests a general decreasing trendof RAA as a function of centrality

p-Pb collisionsThe LHC provided in Run 1 p-Pb collisions at radicsNN = 502 TeV and in Run 2 at

24 Chapter 1 Physics Motivations

Figure 121 φ-meson yield as a function of pT inPb-Pb collisions at radicsNN = 276 TeV in threecentrality classes and two rapidity regions [40]

Figure 122 φ-meson RAA as functionof 〈Npart〉 in Pb-Pb collision at radicsNN =276 TeV and Au-Au and Cu-Cu collisions atradicsNN = 200 GeV [40]

)c (GeVT

p

0 1 2 3 4 5 6 7 8

shy1 )c

(G

eV

T

pd

yd

φN

2d

6minus10

5minus10

4minus10

3minus10

2minus10

1minus10

1

10

210

Centr 0shy10 x 8 Centr 10shy20 x 2

Centr 20shy40 Centr 40shy60

Centr 60shy90 Power law

= 502 TeVNN

sPbshyPb

lt 4y25 lt

ALICE Preliminary

ALIminusPRELminus117465

Figure 123 φ yield as a function of pT for fivecentrality classes in Pb-Pb collisions at radicsNN =502 TeV [41]

rang part

N lang

0 50 100 150 200 250 300 350

AA

R

0

05

1

15 = 502 TeV

NNsPbshyPb

shymicro+micro rarr φ

lt 4y25 lt c lt 7 GeV

Tp2 lt

ALICE Preliminary

ALIminusPRELminus131928

Figure 124 φ nuclear modification factor Rcpas a function of Npart in Pb-Pb collisions atradicsNN = 502 TeV [41]

13 Low-Mass Dimuon Measurements in ALICE 25

radicsNN = 816 TeV Because of the different energy of the proton and Pb beams in

p-Pb collisions the nucleon-nucleon center-of-mass moves in the laboratory with a posi-tive rapidity in the direction of the proton beam The directions of the proton and Pbbeam orbits can be inverted during the p-Pb data taking periods allowing the ALICEmuon spectrometer to access a forward rapidity region when the proton beam is directedtowards the muon spectrometer (203 lt y lt 353) and a backward rapidity region whenthe Pb beam is directed towards the muon spectrometer (minus446 lt y lt minus296)

y

shy4 shy2 0 2 4

(b

)y

dφ

σd

0

005

01

015

02data

HIJING

DPMJET

=502 TeVNN

sALICE pshyPb

c lt 7 GeVT

p1 lt

ALI-PUB-94059

Figure 125 φ-meson cross-section as a func-tion of y in p-Pb collisions at radicsNN = 502 TeVand 10 lt pT lt 70 GeVc Predictions fromHIJING and DPMJET are also shown for com-parison

)c (GeVT

p

0 1 2 3 4 5 6 7

)shymicro

+micro

rarr φ

(F

BR

0

05

1

15

data

HIJING

DPMJET

=502 TeVNN

sALICE pshyPb

|lt353y296lt|

ALI-PUB-94063

Figure 126 φ-meson forward-backward cross-section ratio as a function of pT for 296 lt |y| lt353 in p-Pb collisions at radicsNN = 502 TeVPredictions from HIJING and DPMJET are alsoshown for comparison

Figure 125 reports the φ-meson cross-section as a function of y for p-Pb collisions atradicsNN = 502 TeV showing a clear asymmetry between the forward and backward regions

not reproduced by the predictions of HIJING and DPMJET also shown To establish a moredirect comparison of the φ-meson cross-section in the forward and backward regions thecross-section was extracted as a function of pT in the common |y| range 296 lt |y| lt 353in terms of the ratio RFB between the forward and backward cross-section shown infigure 126 The observation of RFB values significantly different than 1 is consistent withthe observation of the asymmetry in the y dependence of the cross-section reported infigure 125 No significant pT dependence of RFB is visible within statistical and systematicuncertainties

p-Pb data have also been taken in 2016 at radicsNN = 816 TeV with a total integratedluminosity larger than the one of the radicsNN = 502 TeV data taking (see table 22) Theanalysis of this data is currently ongoing and is expected to produce the first preliminaryresults in 2018

pp collisionsLow-mass dimuon data in pp collisions are available at several center-of-mass energiesradics = 276 7 and 8 TeV (data taken during the LHC Run 1) 502 and 13 TeV (data

taken during the LHC Run 2)

26 Chapter 1 Physics Motivations

pp results atradics = 276 TeV [13] are used as a reference for Pb-Pb collisions at

the same radicsNN Figure 127 shows the opposite-sign dimuon signal (after combinatorialbackground subtraction) integrated over the available pT and y ranges compared to theresult of the hadronic cocktail fit the good quality of the data-MC comparison leads toa robust extraction of the φ-meson signal Figure 128 shows the φ-meson differentialcross-section as a function of pT compared to the Levy-Tsallis function [42]

1pT

dNdpTprop1 +

radicpT2 +m2

φ minusmφ

nT

minusn (134)

with n and T as free parameters In figure 128 data are also compared to the predictionsby PHOJET and PYTHIA tunes ATLAS-CSC D6T Perugia0 and Perugia11 As one cansee a good agreement is found between predictions and data except for PYTHIA tunesPerugia0 and Perugia11 which underestimate the cross-section measurement

)2c (GeVmicromicroM

0 02 04 06 08 1 12 14

)2

c (

dim

uo

ns p

er

25

Me

V

micromicro

Md

Nd

0

05

1

15

310times

micromicro

rarrρ

0πmicromicrorarrω

micromicro

rarr φ

γmicromicrorarrrsquoηmicromicro rarr bb

γmicro

micro rarr

η

micromicro

rarr ω

micromicro rarr cc

= 276 TeVspp

lt 4y25 lt

c lt 5 GeV T

p1 lt

micromicro

rarr η

ALICE

ALI-PUB-94035

Figure 127 Dimuon opposite-sign mass spec-trum in pp collisions at

radics = 276 TeV af-

ter combinatorial background subtraction pT-and y-integrated data compared to the hadroniccocktail fit [13]

)c (GeVT

p

0 1 2 3 4 5

))c

(m

b(

Ge

V

Tp

dy

dφ

σ2

d

shy310

shy210

shy110

1 = 276 TeVsALICE pp

lt 4y25 lt

Data

PYTHIA ATLASshyCSC

PYTHIA D6T

PYTHIA Perugia0

PYTHIA Perugia11

PHOJET

LevyshyTsallis

ALI-PUB-94047

Figure 128 φ-meson cross-section as a func-tion of pT in pp collisions at

radics = 276 TeV

Predictions from PHOJET and PYTHIA are alsoshown for comparison as well as the result of afit with a Levy-Tsallis function [13]

Low-mass dimuon data taken in 2015 in pp collisions atradics = 502 TeV offer the

possibility to establish a data-based reference for Pb-Pb and p-Pb data at the sameenergy The opposite-sign dimuon signal in pp collisions at

radics = 502 TeV is shown

in figure 129 integrated over the available pT and y ranges compared to the resultof the hadronic cocktail fit the good quality of the data-MC comparison allows for arobust extraction of the φ-meson signal The pT-differential φ-meson cross-section couldbe extracted up to 6 GeVc as shown in figure 130 compared to different theoreticalmodels

Low-mass dimuon data in pp collisions atradics = 7 TeV allowed for the study of the pT-

differential ω and φ cross-sections The hadronic cocktail fit on the isolated opposite-signdimuon signal is shown in figure 131 The identification of the ω and the φ meson signals

13 Low-Mass Dimuon Measurements in ALICE 27

)2c (GeVmicromicroM

0 02 04 06 08 1 12 14

)2

c (

dim

uo

ns p

er

25

Me

V

micromicro

Md

Nd

1000

2000

3000

4000 = 502 TeVspp

lt 4 y25 lt c lt 7 GeV

Tp1 lt

γmicro

microrarr

η

micromicrorarrρ

micromicro

rarrω

0πmicromicrorarrωmicro

microrarr

φ

γmicromicrorarrrsquoη

cc

bb

γmicro

microrarr

η

micromicrorarrρ

micromicro

rarrω

0πmicromicrorarrωmicro

microrarr

φ

γmicromicrorarrrsquoη

cc

bb

ALICE Preliminary

ALIminusPRELminus131989

Figure 129 Dimuon opposite-sign mass spec-trum in pp collisions at

radics = 502 TeV af-

ter combinatorial background subtraction pT-and y-integrated data compared to the hadroniccocktail fit [41]

)c (GeVT

p

0 1 2 3 4 5 6 7 8

))c

(m

b(

Ge

V

Tp

dy

dφ

σ2

d

3minus10

2minus10

1minus10

1 = 502 TeVspp

ATLASshyCSCD6TPerugiashy0

Perugiashy11PhojetMonashshy2013

ALICE Preliminary

lt 4y25 lt

ALIminusPRELminus132725

Figure 130 φ-meson cross-section as a functionof pT in pp collisions at

radics = 502 TeV [41]

resulted in the measurements of the pT differential cross-section shown in figure 132 for theω-meson only calculation based of PHOJET and PYTHIA with ATLAS-CSC and D6T tunesfairly agree with the data while the Perugia0 and Perugia11 PYTHIA tunes underestimatethe cross-section by about a factor of 2 and 25 respectively (the same conclusions standfor φ-meson)

)2M (GeVc

0 02 04 06 08 1 12 14

)2

dN

dM

(p

air

s p

er

25 M

eV

c

0

1000

2000

3000

4000

cc

micro micro

rarr φ

micro micro

rarr ω

micro micro rarr ρ

γ micro

micro rarr

η

micro micro

rarr η

0π micro micro rarr ω

γ micro micro rarrrsquo η

lt 5 GeVct

1 lt p

= 7 TeVsALICE pp

25 lt y lt 4

ALIminusPUBminus26621

Figure 131 Dimuon opposite-sign mass spec-trum for pp collisions at

radics = 7 TeV after com-

binatorial background subtraction pT- and y-integrated sample compared to the result of thehadronic cocktail fit [43]

Figure 132 ω-meson cross-section as a func-tion of pT in pp collisions at

radics = 7 TeV com-

pared to the predictions of various phenomeno-logical models [43]

Finally low-mass dimuon data are also available in pp collisions atradics = 8 TeV This

28 Chapter 1 Physics Motivations

)2c (GeVmicromicroM

0 02 04 06 08 1 12 14

)2

c (

dim

uo

ns p

er

25

Me

V

micromicro

Md

Nd

0

2000

4000

6000

8000

10000

12000 ALICE Preliminary

s = 8 TeVradicpp

25 lt y lt 4

c lt 80 GevT

p15 lt

γmicromicro

rarr

η

γmicromicro rarrrsquo η0πmicromicro rarr ω

bb

micromicro

rarr ω micro

micro rarr φ

micromicro rarr ρcc

ALIminusPRELminus133143

Figure 133 Dimuon opposite-sign mass spec-trum in pp collisions at

radics = 8 TeV after com-

binatorial background subtraction pT- and y-integrated data compared to the hadronic cock-tail fit [41]

)c (GeVT

p

0 1 2 3 4 5 6 7 8

))c

(m

b(

Ge

V

Tp

dy

d φσ

2d

3minus10

2minus10

1minus10

1hEmpty

Entries 0

Mean x 0

Mean y 0

Std Dev x 0

Std Dev y 0

s = 8 TeVradicpp ATLASshyCSCD6TPerugiashy0Perugiashy11

PhojetMonashshy2013

ALICE Preliminary

lt 4 y25 lt

ALIminusPRELminus133207

Figure 134 φ-meson cross-section as a functionof pT in pp collisions at

radics = 8 TeV [41]

offers the possibility to enrich the study of light neutral meson production in pp collisionsas a function of

radics providing at a same time a useful reference for the p-Pb data at

the same radicsNN energy The available statistics larger than the one in pp collisions atradics = 7 TeV allows to extract the low-mass dimuon analysis up to pT = 80 GeVc On

the other side the higher single muon threshold implies that the analysis could only startfrom pT = 15 GeVc The pT- and y-integrated opposite-sign dimuon signal is shown infigure 133 with the associated hadronic cocktail fit Figure 134 shows the extracted φcross-section as a function of pT compared to three predictions of EPOS-LHC and PYTHIA-8with and without multiple parton interactions As one can see the EPOS-LHC predictionoverestimates the φ cross-section while the comparison to the PYTHIA-8 predictions seemsto favor a scenario including multiple parton interactions

Chapter 2

ALICE at the CERN LHC

Summary21 The Large Hadron Collider 29

211 The CERN accelerator complex 29212 The LHC schedule 30213 The Experimental Heavy-Ion Program 32

22 A Large Ion Collider Experiment (ALICE) 33

221 The Central Barrel 34222 The Forward Detectors 36223 The Muon Spectrometer 38224 The ALICE software framework 40225 The ALICE Upgrade 41

21 The Large Hadron ColliderThe Large Hadron Collider (LHC) straddling the FrenchSwiss border in average100 meter underground in a circular tunnel of some 27 km of circumference is as fornow the worldrsquos largest and most powerful particle collider It operates at the TeVenergy scale with nominal energy of 14 TeV (in pp collision) and 55 TeVnucleon pair(in Lead-Lead) foreseen to be achieved in 2018 To carry out this technical challengethe CERN machine engineers developed a new accelerating technique based on supercon-ducting magnets (NbTi) cooled down to a temperature below 2 K which can generatemagnetic fields up to 8 T Four main experiments have been installed within the LHCring namely ATLAS (A Toroidal LHC ApparatuS) CMS (Compact Muon Solenoid)LHCb (LHC-beauty) and ALICE (A Large Ion Collider Experiment) ALICE will bedescribed in more details in section 22

211 The CERN accelerator complexFigure 21 displays the LHC ring and the full complex of accelerators upstream the LHCFollowing a complete trip from the proton source to the final output within the LHCprotons are produced in the LINAC 2 and then injected in the BOOSTER (PSB forProton Synchroton Booster) first accelerator ring This accelerating stage increases the

30 Chapter 2 ALICE at the CERN LHC

Figure 21 The LHC and the CERN accelerator complex [44]

proton energy from 50 MeV to 14 GeV Once protons have reached the top PSB energythey are injected into the Proton Synchroton (PS) where their energy is ramped up to25 GeV and then into the Super Proton Synchrotron (SPS) (7 km in circumference) tothe nominal energy of 450 GeV The latter is the LHC injector and is used in parallel toprovide particle beam to other CERN experiments (for example NA61SHINE)

In the case of the LHC heavy ions runs the lead ions are firstly accelerated in aLINAC 3 then further accelerated in the Low Energy Ion Ring (LEIR) which increasesthe lead energy from 42 MeV to 72 MeVnucleon before injection in the PS The leadions are then accelerated and injected in the SPS and from there to the LHC

212 The LHC schedule

During the first LHC run (Run 1 2009ndash2013) several energies and three collision systems(pp p-Pb Pb-Pb) have been explored In pp collisions five different center-of-massenergies have been considered 09 236 276 7 and 8 TeV p-Pb and Pb-Pb collisionshave been measured at radicsNN = 502 TeV and radicsNN = 276 TeV respectively Run 1was followed by a first Long Shutdown (LS1) mainly dedicated to the upgrade of theaccelerator system mdash resulting in an increase of the collision energy from 7minus 8 TeV to13minus 14 TeV in proton-proton collisions (from 276 TeV to 502 TeV in Pb-Pb collisions)mdash and the completion of the detectors of some of LHC experiment (in the case of ALICEthe electromagnetic calorimeter and the Transition Radiation Detector were updated)Run 2 started in mid-2016 and is planned to last until the end of 2018 with pp collisionsdelivered at 502 and 13 TeV Pb-Pb collisions delivered at radicsNN = 502 TeV and p-Pbcollision delivered at radicsNN = 502 minus 8 TeV LS2 is foreseen to start at the beginningof 2019 ending in late 2020 during LS2 the installation phase of the ALICE upgrade

21 The Large Hadron Collider 31

program will take place During Run 3 pp and Pb-Pb collisions will be delivered atthe nominal LHC energy (14 TeV for pp and radicsNN = 55 TeV for Pb-Pb) and the firstPb-Pb data taking at high-luminosity will take place LS3 will be mainly devoted to theinstallation of the High-Luminosity LHC (HL-LHC) providing unprecedented luminositiesin pp collisions at the designed LHC energy During LS3 the CMS and ATLAS upgradeprograms will be finalize Run 4 will see the beginning of the HL-LHC program in ppcollisions and the continuation of the high-luminosity heavy ion program

Figure 22 LHC schedule for 2015 to 2035 [45]

a Delivered Luminosity Measurement in ALICE

In high energy physics the luminosity is an essential concept expressing the interactionrate normalized to the intensity of the interacting fluxes of particles In the specific caseof a collider with beam pulsing the luminosity is defined by equation (21) where Nb

is the number of particles per bunch nb is the number of bunches per beam frev therevolution frequency γ is the relativistic gamma factor εn the normalized transversebeam emittance βlowast the beam beta function at the interaction point (for more details seechapter 4 of [46]) and F the geometric luminosity reduction factor due to the crossingangle at the interaction point (IP) [47]

L = N2b nbfrevγ

4πεnβlowastF (21)

The luminosity determination in ALICE is based on visible cross section measurementsperformed during van der Meer (vdM) scans [48 49] In standard vdM scans the twobeams are moved across each other in transverse directions x and y The two scans are

32 Chapter 2 ALICE at the CERN LHC

performed separately and the visible cross section is given by the detectors used for thedefinition of the minimum bias triggering conditions typically the V0 and T0 in ALICE

213 The Experimental Heavy-Ion ProgramThe goal of the LHC heavy-ion program is to produce the hottest the largest and thelongest-lived volumes of QGP in laboratory and to provide a precise characterizationof this new state of matter For that nucleus-nucleus collisions (A-A) are delivered atenergies up to radicsNN = 55 TeV Proton-proton and proton-nucleus collisions are also partof the LHC heavy-ion program providing the needed baseline (in terms of vacuum-likecross-sections and cold nuclear matter effects) allowing for a correct interpretation of theobservations in A-A collisions

In addition to the LHC there are other experimental complexes developing specificheavy-ion programs The most important one is the experimental program implementedat the Relativistic Heavy Ion Collider (RHIC) [50] hosted at the Brookhaven NationalLaboratory (BNL) in Long Island (New York US) RHIC is a dedicated heavy-ion facilityand it has a large flexibility in the choice of both the nuclear species accelerated (fromprotons to Uranium) and the center-of-mass energy (in the range radicsNN = 75minus200 GeV)Four detectors are installed at RHIC one of them STAR still operates today whilePHOBOS BRAHMS and PHENIX completed there operations respectively in 2005 2006and 2016 At CERN a fixed-target heavy-ion program complementary to the LHC one isalso running at the SPS with the NA61SHINE experiment [51] currently performing asystematic scan both in beam energy (radicsNN = 45minus 173 GeV) and colliding system size

In addition to the upgrade of some of the existing experiments several new heavy-ionprograms are under discussion or already in preparation [52]

bull The NICA1 facility at JINR [53] will operate in collider mode in the center-of-massenergy range radicsNN = 4 minus 11 GeV and in fixed-target mode in the center-of-massenergy range radicsNN = 19minus 24 GeV

bull The FAIR2 [54] facility at GSI3 will provide fixed-target collisions in the center-of-mass energy range radicsNN = 2minus 29 GeV

bull The AFTER4 project [55] aiming at running a fixed-target heavy-ion program withthe LHC beams at a center-of-mass energy of radicsNN asymp 72 GeV

bull The NA60+ [5657] is a project of fixed-target experiment based at the SPS focusingon dimuon observables at a center-of-mass energy range radicsNN = 63 ndash 173 GeV

1Nuclotron-based Ion Collider fAcility2Facility for Antiproton and Ion Research3Gesellschaft fuumlr Schwerionenforschung mbH4A Fixed Target ExpeRiment at LHC

22 A Large Ion Collider Experiment (ALICE) 33

22 A Large Ion Collider Experiment (ALICE)

Figure 23 Scheme of the ALICE detector

ALICE is an experiment optimized for the study of the physics of strongly interactingmatter at extremely high energy density focusing in particular on the investigation of theQGP state and the characterization of its properties A key design consideration drivingthe developement of the ALICE detector is the possibility to study the most energeticPb-Pb collisions delivered by the LHC This is done by measuring the particles emergingfrom the interaction region it is achieved by ALICE by exploiting a rich variety of sub-detectors see figure 23 based on different technologies described in the following sections[58] Beyond the heavy-ion program ALICE is also interested in collecting data in proton-proton (pp) and proton-Lead (p-Pb) collisions where no large volumes of deconfinedmatter are supposed to be produced to be used as a reference for the Pb-Pb ones

In table 21 and table 22 the ALICE running conditions in the LHC Run 1 and Run 2respectively are summarized

System ECM [TeV] Year Delivered luminosity

pp

09 2009 196 microbminus1

236 2009 087 microbminus1

276 2011 46 nbminus1

2013 129 nbminus1

7 2010 05 pbminus1

2011 49 pbminus1

8 2012 97 pbminus1

p-Pb 502 2012 15 microbminus1

2013 0891 nbminus1 and 140 nbminus1

Pb-Pb 276 2010 9 microbminus1

2011 146 microbminus1

Table 21 Summary of Run 1 ALICE data taking considered for published or ongoing analyses [59]

34 Chapter 2 ALICE at the CERN LHC

System ECM [TeV] Year Delivered luminosity

pp

502 2015 14951 nbminus1

132015 694 pbminus1

2016 1335 pbminus1

2017 192 pbminus1

p-Pb 502 2016816 2016 868 nbminus1 and 124 nbminus1

Pb-Pb 502 2015 280 microbminus1

Table 22 Summary of Run 2 ALICE data taking considered for published or ongoing analyses [59]

221 The Central Barrel

The ALICE central barrel refers to the assembly of detectors installed around the inter-action point inside the L3 magnet These detectors are dedicated to the tracking andidentification of isolated charged particles and photons as well as to the reconstructionof jets

Inner Tracking System (ITS)

The Inner Tracking System (ITS) is the internal tracker of ALICE It is formed by sixcylindrical layers of silicon detector the innermost one having an internal radius of 39 cmlimited by the external radius of the beam pipe The radius of the outermost layer is430 cm The geometric parameters of the ITS are summarized in table 23

sub-system name layer technology r(cm) plusmnz(cm)

SPD 1 Pixel 39 1412 Pixel 76 141

SDD 3 Drift 150 2224 Drift 239 297

SSD 5 Strip 380 4316 Strip 430 489

Table 23 ITS Geometric features

The pseudo-rapidity coverage of the ITS is |η| lt 09 The six layers are grouped intosix groups of two layers each differing by the adopted technology The two innermost lay-ers are composed of silicon pixel detectors (SPD) the central one of silicon drift detectors(SDD) the two outermost are composed of silicon strip detectors (SSD) The ITS allowsthe position of the primary and secondary (from strange and charmed particles) verticesto be determined with a resolution better than 200 microm in rφ and 300 microm in z directionFurthermore it contributes to the particle identification complementing the informationprovided by the TPC especially for the low momentum particles (p lt 200 MeVc)

22 A Large Ion Collider Experiment (ALICE) 35

Time Projection Chamber (TPC)

The Time Projection Chamber (TPC) is the main detector of the central barrel It iscomposed of a 51 m long cylindrical drift volume of 90 m3 developing between an innerradius of 85 cm and an outer radius of 247 cm This volume is filled with NendashCO2 and isdivided into two parts by the central cathode which is kept at minus100 kV The end platesare equipped with multiwire proportional chambers (MWPC) As the ITS the pseudorapidity coverage is |η| lt 09 In addition to tracking the TPC provides charged-particleidentification via measurement of the specific ionization energy loss dEdx Due to theadopted technology and the large size the TPC is the slowest detector of ALICE thuslimiting the interaction rate that can be supported

Transition Radiation Detector (TRD)

The Transition Radiation Detector (TRD) is composed of eighteen super-modules dividedinto thirty modules arranged in six radial layers and five sectors along the beam directionThe TRD has full azimuth coverage and spans the pseudo-rapidity region |η| lt 09This sub-detector provides particle identification for electrons of momentum larger than1 GeVc

Time-Of-Flight (TOF)

The Time Of Flight (TOF) detector allows the particle time-of-flight to be measuredThe TOF coverage is |η| lt 09 in full azimuth It has a modular structure organized intoeighteen sectors in azimuth and five modules along the beam axis The whole detectoris inscribed in a cylindrical volume with an internal radius of 370 cm and an externalone of 399 cm The TOF has an intrinsic time resolution of about 50 ps thanks to thetechnology of Multi-Resistive Plate Chambers (MRPC)

High-Momentum Particle Identification Detector (HMPID)

The ALICE HMPID is based on proximity focusing Ring Imaging Cherenkov (RICH)counters and consists of seven modules mounted in an independent support cradle fixedto the space frame at the radial distance of 490 cm from the interaction point Thepseudo-rapidity acceptance is |η| lt 06 and an azimuthal coverage develops between 1and 59 corresponding to 5 of the central barrel acceptance The HMPID allows oneto extend the particle identification for π and K up to pT asymp 3 GeVc and pT asymp 5 GeVcfor protons

PHOton Spectrometer (PHOS)

The PHOton Spectrometer (PHOS) is a high resolution electromagnetic spectrometercovering the pseudo-rapidity range |η| lt 013 and the azimuth between 220 to 320 andinstalled at the radial distance of 460 cm The detector technology is based on lead-tungstate (PbWO4) crystals The PHOS is used to detect photons in the transversemomentum range between 05 to 10 GeVc including diphotons coming from the decayof the light pseudoscalar neutral mesons

36 Chapter 2 ALICE at the CERN LHC

ElectroMagnetic Calorimeter (EmCal)

The ElectroMagnetic Calorimeter (EMCal) and its extension the Di-jet Calorimeter(DCal) are sampling electromagnetic calorimeters with the pseudo-rapidity coverage|η| lt 07 and azimuth coverage from 80 to 187 (for the EMCal) and 260 to 327 (for theDCal) Specific allowance is made in the DCal acceptance for the space occupied by thePHOS detector The combined information of the EmCal and the DCal allows to studyjets and di-jets providing trigger signals for hard jets photons and electrons

222 The Forward DetectorsIn this section the ALICE sub-detectors covering the forwardbackward acceptance regionare presented These detectors are used to measure global observables especially thecentralityactivity of the collisions and the event plane

Forward Multiplicity Detector (FMD)

The Forward Multiplicity Detector (FMD) is based on the silicon strip technology Itis divided in seven disks perpendicular to the beam pipe located at distances between42 and 225 cm from the interaction point The goal of this sub-detector is to study thecharged particle multiplicity in the pseudo-rapidity ranges minus34 lt η lt minus17 and17 lt η lt 51 complementary to the one of the ITS

T0

The T0 is composed of two arrays of Cherenkov counters circularly arranged around thebeam pipe with a time resolution better than 50 ps The forward and backward parts ofthis sub-detector are located at 375 cm and minus727 cm covering a pseudo-rapidity rangeof 461 lt η lt 492 and minus328 lt η lt minus297 respectively It participates to thetrigger decision and to the estimation of the luminosity

V0

The V0 is composed of two scintillator disks installed around the beam axis on each sideof the interaction point The V0-A (for A-side corresponding to positive values of z) isinstalled at 329 cm from the interaction point it has a diameter of 100 cm and covers thepseudo-rapidity range 28 lt η lt 51 The V0-C (for C-side corresponding to negativevalues of z) is installed at minus90 cm from the interaction point it has a diameter of 74 cmand covers the pseudo-rapidity range minus37 lt η lt minus17

The V0 measures the charged particle multiplicity and by the measurement of thetime-of-flight difference between the A and C scintillators makes possible to identify andreject the beam-gas5 events This technique is illustrated in figure 24 beam-beam andbeam-gas events can be easily discriminated on the basis of the time correlation of thetwo signals reported on the x and y axes

5 A beam-gas event corresponds to an interaction between a beam ion and a nucleus of the residualgas in the beam pipe vacuum

22 A Large Ion Collider Experiment (ALICE) 37

Figure 24 Weighted average time-of-flight of the particles detected in V0-C versus V0-A Thedashed line intersection represents the time of the collisions at the interaction point or the crossingtime of the background tracks at the vertical plane z = 0 [60]

The V0 participates in the minimum-bias trigger decision and in the estimation of theluminosity Furthermore this sub-detector is involved in the centrality measurement inPb-Pb collisions

Photon Multiplicity Detector (PMD)

The Photon Multiplicity Detector (PMD) consists of two identical planes of detectorsmade of gas proportional counters with honeycomb structure and wire readout with Leadconverter in between located at 360 cm from the interaction point in opposite side ofmuon spectrometer The PMD covers the pseudo-rapidity region (23 lt η lt 37) Itmeasures the multiplicity and spatial distribution of photons and estimates the transverseelectromagnetic energy and the reaction plane event-by-event

ALICE Diffractive Detector (AD)

The ALICE Diffractive detector (AD) is a ALICE sub-detector which was installed dur-ing the Long Shutdown 2 (2013-2014) The goal of this sub-detector is to increase thepseudo-rapidity coverage (from 88 to 132 units) and to enhance trigger efficiency forlight particles produced in diffractive events This sub-detector also participates in theestimation of the multiplicity event-by-event It is composed of two double layers of scin-tillator counters one on each side of ALICE sensitive to charged particles with pT downto 20 MeVc In the A-side AD is installed at z = 170 m and covers the pseudo-rapidityrange 49 lt η lt 63 In the C-side the sub-detector is installed at z = minus195 m andcovers the pseudo-rapidity range minus70 lt η lt minus48

38 Chapter 2 ALICE at the CERN LHC

Zero Degree Calorimeter (ZDC)

The Zero Degree Calorimeter (ZDC) is composed of two identical sets of quartz spaghetticalorimeters located on both sides of the ALICE detector in fully horizontal position1125 m from the interaction point Each set of detectors consists of a neutron anda proton calorimeter Each of the neutron calorimeters has dimensions 7x7x100 cm3

while the proton calorimeters have dimensions 228x12x150 cm3 The ZDC detector iscompleted by two small electromagnetic calorimeter (ZEM) placed at 735 m from theinteraction point on one side detecting the energy of particles emitted in the pseudo-rapidity range 48 lt η lt 57 The ZDC is used to estimate the centrality in Lead-Leadcollisions

223 The Muon Spectrometer

Figure 25 The ALICE muon spectrometer layout [61]

The ALICE muon spectrometer (represented in figure 25) is 17 m long Thepseudo-rapidity coverage is minus40 lt η lt minus25 corresponding to the angular range171 lt θ lt 178 The muon spectrometer was designed to study quarkonia (Jψand Υ families) and light vector meson production (η ρω and φ) through their dimuondecays and open charm and beauty production (B and D hadrons) in the single-muonchannel The spectrometer is composed of several elements described in the followingsections

a Front Absorber

The first element of the ALICE muon spectrometer starting from the interaction pointis the front absorber (or hadron absorber) The hadron absorber suppresses all particlesexcept muons coming from the interaction vertex (mainly πplusmn and Kplusmn) It is made of

22 A Large Ion Collider Experiment (ALICE) 39

carbon and concrete (cf figure 26) in order to limit the multiple scattering and theenergy loss of the muons The inner beam shield protects the tracking chambers frombackground originating from particles at small angles It is made of tungsten lead andstainless steel to minimize the background arising from primary particles emitted in thecollision and from their showers produced in the beam pipe and in the shield itself

Figure 26 The ALICE front absorber structure [62]

The absorber is located 90 cm away from the interaction point just after the V0-Cand is 413 cm long

b Dipole Magnet

The dipole magnet provides a maximum magnetic field of 07 T and an integral fieldof 3 T middot m It is a warm magnet (one of the largest warm dipoles in the world) andit is cooled with a demineralized water-cooling system ensuring operating temperaturesbetween 15 to 25 C Its dimensions are 5 m in length 71 m in width and 9 m in heightThe dipole is centered at 994 m from the interaction point and the free gap betweenpoles has a diameter of approximately 3 m The dipole is designed to provide a horizontalmagnetic field perpendicular to the beam axis and its polarity can be reverted Themagnetic field is defined by requirements on the mass resolution for the heavy Υ states

c Tracking Chambers

The tracking system of the muon spectrometer is composed of five stations each sta-tion made of two chambers The distance between two chambers of a same station isbetween 10 and 20 cm The chambers are based on a Multiwire Proportional Cham-ber (MWPC) technology with pad-segmented cathodes [63] The tracking system wasdesigned to achieve the spatial resolution of 100 microm in the bending plane needed for ob-taining an invariant mass resolution of sim 100 MeVc2 at the Υ mass The segmentationof the cathodes allows the spectrometer to operate with maximum hit densities of about5 middot 10minus2 cmminus2 sufficiently large to cope with the observed multiplicity in central Pb-Pbcollisions

40 Chapter 2 ALICE at the CERN LHC

d Iron Wall

The iron wall complements the hadron absorber It is 12 m thick and covers a transversesurface of 56times 56 m2 It is located 15 m away from the interaction point before thetrigger chambers The goal of this element is to suppress all hadrons emerging from thefront absorber The combined action of the iron wall and the front absorber imposesthe muons to have a minimum momentum of sim 4 GeVc in order to reach the triggerchambers

e Trigger Chambers

The ALICE muon spectrometer is equipped with two trigger stations allowing events ofinterest for the muon physics to be selected Each station is composed of two chambersbased on the Resistive Plate Chamber (RPC) technology ensuring the time resolution of2 ns necessary for the identification of the bunch crossing The first station is located at16 m just after the iron wall and the second station at 17 m

Several trigger conditions are hard-coded in the trigger electronics The electronicsprovides the possibility to use two pT thresholds used for different physics and the list oftriggers is

bull MSL at least one muon with pT larger than the low-pT threshold

bull MSH at least one muon with pT larger than the high-pT threshold

bull MLL at least two muons of same charge with pT larger than the low-pT threshold

bull MUL at least two muons of opposite charge with pT larger than the low-pT thresh-old

In addition to these trigger conditions the A-pT trigger condition can also be defined itis the minimum-pT trigger threshold for which a muon is firing the trigger and the valueof this trigger is 05 GeVc

In LHC Run 2 the single-muon high-pT threshold was set to 42 GeVc while thevalue of the single-muon low-pT threshold depended on the data taking periods In thepp data taking during Run 2 two different values have been considered for the single-muonlow-pT threshold 1 GeVc allowing one to access φ meson pT down to sim 15 GeVc and05 GeVc allowing one to access φ meson pT down to almost 0 GeVc

224 The ALICE software frameworkThe ALICE software (AliRoot [64] and AliPhysics [65]) is based on ROOT [66] a soft-ware originally designed at CERN for particle physics data analysis ROOT AliRoot andAliPhysics are written in C++ and are used to handle the online-offline data The soft-ware also manages the Monte-Carlo simulation framework by interfacing several MCgenerators (PYTHIA [67] HIJING [68]) and particle transport codes which simulate thedetector response (GEANT3 [69] GEANT4 [70] and FLUKA [71])

The working flow of the ALICE software is represented in figure 27 where the mainstructures of the online-offline handling are shown The reconstruction steps are the

22 A Large Ion Collider Experiment (ALICE) 41

same for the raw data and MC data At the end of the reconstruction chain the dataare available in the AOD format (Analysis Object Data) From the AOD data furtherdata formats can be derived designed for any specific analysis In the case of the analysisperformed in this thesis the AOD events are reduced to the AliLMREvent format containingthe information of interest for the study of light-neutral meson production decaying intomuons

Simulation Reconstruction

Mon

teCarlo

RealData

Particles

HitsSDigitsSDigits Digits

Clusters

Vertex

Tracks ESD AOD

Trigger

Detector

HLT

DAQ Raw Data

Online Offline

Figure 27 Schema of the reconstruction chain for data and simulation

225 The ALICE UpgradeDuring LHC Run 1 and Run 2 the goal of ALICE is to explore the unprecedented energyregime available in heavy ion collisions see section 124 In the LHC Run 3 and Run 4ALICE we move from the exploration phase to a precision-measurement phase For thisreason ALICE is undertaking a complex upgrade program of its detectors with theinstallation of the upgraded sub-detectors to take place in 2019ndash2020 during the LHCLong Shutdown 2

Physics Motivations

The ALICE upgrade will preserve the specificities of the ALICE physics program withrespect to the other LHC experiments The track reconstruction performance will beimproved in terms of spatial precision and efficiency in particular for low-momentumparticles in order to select more efficiently the decay vertices of heavy-flavor mesons andbaryons The particle identification capabilities of the apparatus will be consolidatedthey represent a crucial tool for the selection of heavy-flavor quarkonium and dileptonsignals at low momentum In the following the main items of the foreseen physics programare shortly reviewed

42 Chapter 2 ALICE at the CERN LHC

bull Heavy Flavors characterization of the parton energy loss study of the transportof heavy quarks in the medium and the hadronization of heavy flavors In ALICE thefocus is placed on the low-momentum region down to zero pT and the reconstructionof heavy-flavor hadrons (mesons and baryons) and the possibility to measure theflavor-dependence in low-momentum jets using light flavor strange and charmedhadrons reconstructed within jets

bull Quarkonia study of the quarkonia dissociation (and possible regeneration) asprobe of the deconfined nature and temperature of the medium In ALICE theemphasis is in the low-momenta region and the possibility to study Jψ ψ(2S) andΥ in central and forward rapidity At forward rapidity in particular the MuonForward Tracker (MFT) will allow the prompt Jψ component to be statisticallyseparated from the displaced production and the ψ(2S) to be observed even inthe most central PbndashPb collisions thanks to a strong reduction of the non-promptbackground

bull Low-Mass Dileptons and Thermal Photons estimation of the initial temper-ature of the medium and investigation of the chiral nature of the phase transitionALICE will access this physics both in the dielectron and dimuon channels down tozero pT

bull Beyond Standard Model specific studies are also undergoing to assess the sen-sitivity of ALICE to the measurement of possible low-mass dark matter bosonsdecaying into electron or muon pairs thanks to the improvement of the discrimina-tion between prompt and non-prompt dileptons

Inner Tracking System (ITS)

The current ALICE Inner Tracking System (ITS) will be totally dismounted at the endof the LHC Run 2 to be replaced by a new detector during Long Shutdown 2 The newITS [72] will be composed of seven cylindrical layers of Monolithic Active Pixel Sensors(MAPS) the innermost one having an internal radius of 224 mm limited by the externalradius of the future beam pipe The internal radius of the outermost layer is 3918 mm

The hit resolution of the detector will be of about 5 microm and the material budget ofthe three innermost layers will be reduced from the present 11 to 03 of the radiationlength per layer these features provide an improvement by a factor about three for thetrack impact parameter resolution in the transverse plane The new ITS would have apseudo-rapidity coverage of |η| lt 122 This upgrade will improve the precision in thesecondary vertex separation (from beauty charm and strange particle decays)

Muon Forward Tracker

The Muon Forward Tracker (MFT) [73] will be a new sub-detector of ALICE made of fivedisks of the same MAPS used in the upgraded ITS The MFT will provide precise track-ing and secondary vertex reconstruction for muon tracks in the pseudo-rapidity regionminus36 lt η lt minus25 within the acceptance of the muon spectrometer

22 A Large Ion Collider Experiment (ALICE) 43

Figure 28 Simulation of low-mass dimuons with and without ALICE upgrade

The measurement of prompt dimuon sources in the low-mass region will strongly ben-efit from the addition of the MFT to the muon spectrometer A significant improvementup to a factor of about 4 is expected for the mass resolution of the narrow resonancesη ω and φ for which resolutions of sim 15 MeVc2 are expected (to be compared withthe current sim 50 MeVc2 resolution at the mass of the φ meson see figure 28) thiswill translate into a significant improvement of the measurements involving these parti-cles allowing at the same time a reliable identification of the underlying thermal dimuoncontinuum and the measurement of the in-medium modified line shape of the short-livedρ meson A precision of about 20 is expected for the observation of these sourcescurrently not feasible due to the very small signal-over-background ratio affecting themeasurement with the present muon spectrometer

TPC

The expected increase of the LHC luminosity after LS2 corresponding to an interactionrate about 50 kHz in PbndashPb implies that TPC operation with a gating grid is no longerpossible This motivates the choice of GEMs for the new readout chambers since theyfeature intrinsic ion blocking capabilities that avoid massive charge accumulation in thedrift volume from back-drifting ions and prevent excessive space-charge distortions Thepresent particle identification (PID) capability via the measurement of the specific ioniza-tion dEdx and the combined momentum resolution of the central barrel tracking systemmust be retained by the TPC upgrade [74] preserving the excellent performance of thecurrent detector

Fast Interaction Trigger (FIT)

The Fast Interaction Trigger (FIT) [75] will be a new sub-detector of ALICE expectedto match and even exceed the functionality and performance (fast event triggering min-imum bias luminosity and charged-particle multiplicity measurements) currently secured

44 Chapter 2 ALICE at the CERN LHC

by three ALICE sub-detectors the T0 the V0 and the FMD detectors The location ofFIT will be similar to that of the current V0 and T0 modules with sensors on both sidesof the Interaction Point (IP) The restrictions imposed by the desired functionality tightspace requirements and the need to minimize the material in the vicinity of the inter-action point have narrowed the choice of detector technologies for FIT to either plasticscintillator- andor Cherenkov radiator

ALICE O2 (ALICE Online-Offline)

After the LHC LS2 the Pb-Pb collision interaction rate will be approximately 50 kHzSince the ALICE physics program will focus on untriggerable signals a continuous read-out will be required in order for all events to be recorded The resulting data throughputfrom the detector has been estimated to be larger than 1 TBs for PbminusPb events roughlytwo orders of magnitude more than in Run 1 and Run 2 To minimize the costs and therequirements of the computing system needed for data processing and storage ALICE isdeveloping a new Computing Framework for Runs 3 and 4 called ALICE Online-Offline(ALICE O2) [76] This framework is designed for a maximal reduction of the data volumeread out from the detector as early as possible during the data-flow

Chapter 3

Data Sample Selection andIntegrated Luminosity Evaluation

Summary31 Data Sample Event and Track Selection 45

32 Integrated Luminosity Evaluation 46

321 F inorm Calculation 47

322 The MB Trigger Cross Section 50

323 Lint Evaluation 51

31 Data Sample Event and Track SelectionThe analysis presented in this thesis is based on a data sample collected by ALICE in2016 in pp collisions at

radics = 13 TeV amounting to asymp 26 times 108 events recorded with

a dimuon trigger This is the largest data sample recorded with the low-pT threshold atsim 05 GeVc as of today (September 2017)

The ALICE data taking is organized into two levels at the first level data are orga-nized into periods each one characterized by the same detector and beam configurationsat the second level data within a given period are further organized into runs each onespanning the interval of two consecutive stops in the data acquisition1 Runs retained forthe analysis are selected on the basis of the quality assurance conditions defined for themuon spectrometer These conditions imply the good operation of all detectors involvedin the analysis of the muon data (muon tracking chambers muon trigger chambers SPDlayers of the ITS V0 and T0) The full list of runs used for the present analysis is reportedin appendix A

The Minimum-Bias (MB) trigger condition for the considered data sample is givenby the logical AND of the signals given by the two V0 detectors (V0AND) [48] Eventscontaining a muon pair are selected by means of a specific dimuon trigger based on thedetection of two muon candidate tracks in the trigger system of the muon spectrometerin coincidence with the MB condition Due to the intrinsic momentum cut imposed bythe detector only muons with pTmicro amp 05 GeVc manage to leave a signal in the triggerchambers Both unlike-sign and like-sign dimuon triggers were collected the like-sign

1 The data acquisition can be stopped either because of beam-related or detector-related issues

46 Chapter 3 Data Sample Selection and Integrated Luminosity Evaluation

trigger sample was downscaled by a factor that varied from run to run according to theinstantaneous luminosity

Background events not coming from beam-beam interactions are rejected by perform-ing an offline selection based on the timing information from the V0 detectors Moreoverit is requested that at least one SPD tracklet contributes to the vertex reconstructed bythe ITS

Track reconstruction in the muon spectrometer is based on a Kalman filter algo-rithm [43 77 78] Muon identification is performed by requiring the candidate track tomatch a track segment in the trigger chambers (trigger tracklet) This request selectsmuons with pTmicro amp 05 GeVc and as a consequence significantly affects the collectedstatistics for dimuons with invariant mass 1 GeVc2 and pT 1 GeVc A harder pro-grammable pT threshold can be imposed on single muons when defining the trigger condi-tions according to the specific physics target it was not the case for the data consideredin the present analysis for which the trigger condition was based on any trigger-matchedmuon Due to the geometrical acceptance of the muon spectrometer the pseudo-rapidityselection minus400 lt ηmicro lt minus250 on the muon tracks is imposed where ηmicro is defined in thelaboratory frame in order to remove the tracks close to the acceptance borders of thespectrometer where the acceptance drops abruptly Muon pairs are built combining twomuon tracks that satisfy the cuts mentioned above

The invariant mass spectrum was obtained both for Opposite-Sign (OS) and Like-Sign (LS) muon pairs the latter being considered for background subtraction relatedpurpose It should be noted that the OS component coming from the LS triggers wassafely neglected in the analysis so that only LS pairs were extracted from the LS-triggeredevents they were upscaled run by run by the inverse of the downscaling factor appliedin the data taking

32 Integrated Luminosity EvaluationThe integrated luminosity for the considered data sample was evaluated as Lint =NMBσMB where NMB is the equivalent number of MB events for the analyzed eventsample and σMB the MB trigger cross section The value of NMB was obtained by usingthe following formula

NMB =sumi=run

F inorm timesN i

MUL (31)

where the N iMUL is the number of events fulfilling the unlike-sign dimuon trigger condi-

tion (MUL given by the presence of at least two tracklets in the muon trigger systemof opposite sign both satisfying the single-muon pT-trigger condition) and F i

norm is thenormalization factor to convert the number of MUL events in the analyzed sample to theequivalent number of MB events In the present analysis two conditions are consideredto estimate the number of MB events

bull The first condition (in the following referred to as ldquoV0rdquo) is theCINT7-B-NOPF-MUFAST one This condition is defined by the coincidence oftwo signals in the V0-A and -C sub-detectors with the requirement that the

32 Integrated Luminosity Evaluation 47

coincidence actually comes from a valid beam-beam interaction (B-NOPF) It is alsorequired that the detectors implied in the definition of the MUL trigger conditionare also included in the readout for the considered M B events this is guaranteedby the composition of the specific MUFAST trigger cluster containing the SPDMUON_TRK MUON_TRG T0 V0 and AD detectors

bull The second condition (in the following referred to as ldquoT0rdquo) is based on the coinci-dence of the above condition CINT7-B-NOPF-MUFAST and the level-0 trigger condition0TVX defined by the coincidence of two signals in the T0-A and -C sub-detectors

321 F inorm Calculation

Three methods are usually considered to compute the Fnorm factor run by run one basedon the counting scaler information (online method) and two based on the reconstructeddata (offline methods)

Pile-Up correction

Regardless of the method one needs to estimate the pile-up contribution in order toproperly correct the estimation of NMB The pile-up correction factor (PU) is defined fora given run i as

PU i = microi

1minus eminusmicroi

microi = minus ln1minus FMBi

purity times L0biMB

Di timesN icolliding times fLHC

where

bull fLHC is the frequency of one bunch in the LHC (11245 Hz)

bull N icolliding is the number of colliding bunches

bull Di is the run duration as given by the Central Trigger Processor (CTP)

bull L0biMB is the scaler input of the level-0 trigger for the considered MB condition

bull FMBipurity is the purity factor associated to the considered MB condition

The purity factor for a generic trigger condition X is computed offline as the fractionof physics-selected (PS) X-trigged events [79] divided by the total number of X-triggedevents

FXipurity = N i

X(PS)N iX(ALL) (32)

In the case of the ldquoT0rdquo MB condition the purity factor is considered equal to 1Figure 31 shows the evolution of the purity factor for all the periods involved in thisanalysis and for the MUL and the ldquoV0rdquo MB trigger conditions

Figure 32 shows the evolution of the pile-up correction factor for the periods involvedin this analysis and for the two conditions considered for the estimate of the number ofMB events

48 Chapter 3 Data Sample Selection and Integrated Luminosity Evaluation

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

0

02

04

06

08

1

Purity factor for MUL

Purity factor for V0 MB condition

B TeyssierWork Thesis

Figure 31 Purity factor for the periods f to p in chronological order

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Pile

-Up

corr

ectio

n fa

ctor

1

105

11

115T0 evaluation

V0 evaluation

B TeyssierWork Thesis

Figure 32 Pile-Up correction for the periods f to p in chronological order

Fnorm Evaluation with Online Method

The online method for the evaluation of the Fnorm factor is based on the information ofthe L0b scaler inputs for the MUL and MB triggers conditions In this case F i

norm iscomputed for a given run i as

F inorm = PU i times FMBi

purity times L0biMB

FMULipurity times L0biMUL

(33)

where FXipurity is the purity factor associated to the events selected by the trigger condition

X This method does exploit the full event sample in the analyzed data The run-by-run

32 Integrated Luminosity Evaluation 49

evolution of the F inorm factor evaluated with this method is given in figure 33 both for

the ldquoV0rdquo and ldquoT0rdquo MB conditions

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Nor

mF

0

2

4

6

310times

method Online V0NormF

method Online T0NormF

B TeyssierWork Thesis

Figure 33 Normalization factor for the periods f to p in chronological order evaluated with theonline method both for the ldquoV0rdquo and ldquoT0rdquo MB conditions

Offline Methods

The offline methods are based on the comparison between the number of minimum biasevents in a given data sample and the number of minimum bias events in the same datasample satisfying at the same time the trigger condition of the analyzed events at thelevel-0 For the first offline method the following formula is used for a given run i

F inorm = PU i times MBi

(MBamp0MUL)i (34)

where

bull MBi is the number of physics-selected MB events

bull (MBamp0MUL)i is the number of physics-selected MB events also fulfilling the MULtrigger condition at the level-0

The run-by-run evolution of the F inorm factor evaluated with this method is given in

figure 34 both for the ldquoV0rdquo and ldquoT0rdquo MB conditionsThe second offline method is based on the formula

F inorm = PU i times MBi

(MBamp0MSL)i timesMSLi

(MSLamp0MUL)i (35)

where

50 Chapter 3 Data Sample Selection and Integrated Luminosity Evaluation

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Nor

mF

0

2

4

6

8

10

12310times

method Offline 1 V0NormF

method Oflline 1 T0NormF

B TeyssierWork Thesis

Figure 34 Normalization factor for the periods f to p in chronological order evaluated with the firstoffline method both for the ldquoV0rdquo and ldquoT0rdquo MB conditions

bull MSLi is the number of physics-selected events satisfying the single-muon triggercondition (MSL given by the presence of at least one tracklet in the muon triggersystem passing the all-pT single-muon threshold) in coincidence with the ldquoV0rdquo MBcondition

bull (MSLamp0MUL)i is the number of physics-selected MSL events (see above) also satis-fying the MUL trigger condition at the level-0

bull (MBamp0MSL)i is the number of physics-selected MB events also satisfying the MSLtrigger condition at the level-0

The run-by-run evolution of the F inorm factor evaluated with this method is given in

figure 35 both for the ldquoV0rdquo and ldquoT0rdquo MB conditionsThe relative rate of the MSL trigger condition relative to the MB and the MUL ones is

larger than the relative rate of the MUL trigger condition to the MB one this guaranteesthis second offline method to profit from a larger event sample resulting in a smallerstatistical uncertainty As expected the results from the two offline methods agree withinthe error bars

322 The MB Trigger Cross SectionThe ldquoMBrdquo cross section σMB was measured with a van der Meer scan for both theldquoV0rdquo and ldquoT0rdquo MB condition and found to be 578plusmn 12 mb for the ldquoV0rdquo conditionand 301plusmn 06 mb for the ldquoT0rdquo condition [80] As reported in [80] ldquowhen the LHC isoperated with isolated-bunch-based filling schemes the two detectors provide indepen-dent measurements of the luminosity with a total uncertainty of 23 When the LHC isoperated with bunch trains the V0-based luminosity is affected by non-trivial systematiceffects in this case the total uncertainty on the luminosity measured with T0 is 34rdquo

32 Integrated Luminosity Evaluation 51

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Nor

mF

0

2

4

6

8

10

12310times

method Offline 2 V0NormF

method Offline 2 T0NormF

B TeyssierWork Thesis

Figure 35 Normalization factor for the periods f to p in chronological order evaluated with thesecond offline method both for the ldquoV0rdquo and ldquoT0rdquo MB conditions

It should be noted that these values refer to the pp data taking of 2015 since thecorresponding results from the van der Meer scan of 2016 (when the data considered inthe present analysis were taken) is not available yet We thus currently assume a 5additional systematic uncertainty on σMB accounting for any possible difference betweenthe efficiency of the detectors involved in the MB trigger conditions between 2015 and2016

323 Lint EvaluationTo obtain the value of Lint for the data taking periods considered in this present analysisone has to assume a reference MB condition and a reference method for the evaluationof Fnorm From equation (31) one can expect that for a given MB condition the valuesof Fnorm coming from the online and offline methods discussed above agree between eachother to give the same estimation of NMB Moreover the definition of the integratedluminosity Lint = NMBσMB implies that the ratio between the NMB(V0) and NMB(T0)and then the ratio between Fnorm(V0) and Fnorm(T0) should be consistent with the ratiobetween σMB(V0) and σMB(T0) As one can see by comparing figures 33 to 35 thethree evaluation methods give compatible estimations for Fnorm However the expectedratio between the ldquoV0rdquo and ldquoT0rdquo estimations of Fnorm is only observed with the onlinemethod For this reason the online method (which also profits from the smaller statisticaluncertainties) is retained for the evaluation of the Lint value to be used for the presentanalysis

The resulting values of Lint are 844plusmn 000(stat)plusmn 042(syst) pbminus1 and904plusmn 000(stat)plusmn 452(syst) pbminus1 respectively when the ldquoT0rdquo and ldquoV0rdquo MBconditions are considered The ldquoT0rdquo MB condition assuring the most stable referenceis finally retained and considered in the present analysis

Chapter 4

Monte Carlo Simulations

Summary41 Light-Meson Decays 53

411 Kinematical Distributions 54412 Dalitz Decays 54413 Two-Body Decays 57

42 Dimuons from Open Heavy-Flavor Decays 60421 PYTHIAndash FONLL Comparison 61422 Decay Chain Length in the Open Heavy-Flavor Processes 62

This thesis work is devoted to the study of light-meson production decaying in two-muon (dimuon) channel The dimuon mass range of interest for this study goes fromthe production threshold (Mmicromicro = 2mmicro) to 15 GeVc2 and is named Low-Mass Region(LMR) This region gives access to the dimuon decays of the light vector (ρ ω and φ)and pseudo-scalar (η and ηprime) mesons discussed in section 41 In addition to these decaysa correlated dimuon continuum is also present in the LMR this contribution is treated insection 42 in terms of open charm and beauty processes

For each process discussed in the following the underlying physics is reviewed andthe main details of the corresponding MC simulations are given All the MC simulationsperformed in this thesis used GEANT3 as transport code

41 Light-Meson DecaysThe properties of the light mesons contributing to the LMR through their dimuon de-cays are reported in table 41 These mesons contribute to the LMR with two types ofdecays the two-body decays and the three-body (Dalitz) decays which will be discussedseparately in the following section All the light-meson decays involved in the LMR aresimulated with the AliGenMUONLMR parametric generator

As can be seen from the quark composition reported in table 41 the ρ and ω mesonscan be used as reference for particle production in the (ud) quark sector while strangenessproduction can be accessed via φ meson (and to a lesser extent η and ηprime mesons)measurement The physical width of the ρ meson significantly larger than one of theother particles contributing to the LMR corresponds to the life time of sim 13 fmc thismakes the ρ an ideal probe of in-medium modifications in the case of QGP productiongiven that a large fraction of the observed ρ mesons would decay inside the hot medium

54 Chapter 4 Monte Carlo Simulations

Particle Pole Mass [MeVc2] Width [MeVc2] Quark Compositionη 547862plusmn 0018 (131plusmn 005) middot 10minus3 1radic

6

(uu + ddminus 2ss

)ρ 77526plusmn 025 1491plusmn 08 1

2

(uuminus dd

)ω 78265plusmn 012 849plusmn 008 1

2

(uu + dd

)ηprime 95778plusmn 006 0198plusmn 0009 1radic

3

(uu + dd + ss

)φ 1019461plusmn 0019 4266plusmn 0031 ss

Table 41 Property of light-mesons involved in the dimuon mass spectrum values taken from [4]

411 Kinematical DistributionsThe kinematics parametrization of the light mesons in the AliGenMUONLMR generator areprovided by a pT-y distribution estimated by PHOJET [81 82] (based on a Dual PartonModel combined with perturbative QCD)

412 Dalitz DecaysAmong the light mesons reported in table 41 the η ω and ηprime mesons give a sizableDalitz decay contribution to the LMR The involved decay channels are summarized intable 42

Process Branching Ratio (BR)ηrarr micro+microminusγ (31plusmn 04) middot 10minus4

ωrarr micro+microminusπ0 (13plusmn 06) middot 10minus4

ηprime rarr micro+microminusγ (108plusmn 027) middot 10minus4

Table 42 Dalitz decay processes in the LMR and the branching ratios used in the analysis

The Feynman diagram corresponding to the Dalitz decay under discussion are shownin figure 41 In the considered processes the parent mesons decay electromagnetically intoone virtual photon with mass M and a third body (real photon or π0) with the virtualphoton converting into a muon pair

η

γlowast

microminus

micro+

γ

1(a) ηrarr micro+microminusγ

ω

γlowast

microminus

micro+

π0

1(b) ωrarr micro+microminusπ0

ηprime

γlowast

microminus

micro+

γ

1(c) ηprime rarr micro+microminusγ

Figure 41 Feynman diagrams of the Dalitz decays of interest for the dimuon LMR

The ALICE muon spectrometer is not equipped for detecting neither the real photonnor the π0 emitted within the Dalitz decays discussed here these decays are identified by

41 Light-Meson Decays 55

]2c [GeV-micro+microM0 01 02 03 04 05 06 07 08

- micro+ micro

MdN

d

0

5

10

15

20

610times (gen)γ-micro+micro rarr η

(a) η

]2c [GeV-micro+microM0 02 04 06 08 1

- micro+ micro

MdN

d

0

2

4

6

610times (gen)0π-micro+micro rarr ω

(b) ω

]2c [GeV-micro+microM0 02 04 06 08 1 12

- micro+ micro

MdN

d

0

1

2

3

4

5610times (gen)γ-micro+micro rarr η

(c) ηprime

Figure 42 Generated dimuon mass distribution of Dalitz decay integrated in full phase space

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

γmicromicrorarrη for -micro+micro)ε times(A

(a) η

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

0πmicromicrorarrω for -micro+micro)ε times(A

(b) ω

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

γmicromicrorarrη for -micro+micro)ε times(A

(c) ηprime

Figure 43 Acceptance times efficiency of Dalitz decay

]2c [GeV-micro+microM0 01 02 03 04 05 06 07 08

- micro+ micro

MdN

d

0

005

01

015

02

610times (rec)γ-micro+micro rarr η

(a) η

]2c [GeV-micro+microM0 02 04 06 08 1

- micro+ micro

MdN

d

0

20

40

60

80

100

310times (rec)0π-micro+micro rarr ω

(b) ω

]2c [GeV-micro+microM0 02 04 06 08 1 12

- micro+ micro

MdN

d

0

20

40

60

80

310times (rec)γ-micro+micro rarr η

(c) ηprime

Figure 44 Reconstructed dimuon mass distribution of Dalitz decay integrated in full phase space

56 Chapter 4 Monte Carlo Simulations

looking at the mass distribution of the dimuons coming from the virtual photon conversionFor this reason it is important to have a theoretical description of the shape of suchmass distributions they can be computed in pure QED under the hypothesis of a point-like electromagnetic transition vertex with the deviation from the real transition vertexquantified by a form factor |F (M2)|2 see Equations (41) to (43)

dΓ (ηrarr micromicroγ)dM = 2M 2

3α

π

Γ (ηrarr γγ)M2

(1minus M2

m2η

)3 (1 +

2m2micro

M2

)

timesradicradicradicradic(1minus 4m2

micro

M2

) ∣∣∣Fη (M2)∣∣∣2

(41)

dΓ (ωrarr micromicroπ0)dM = 2M α

3πΓ (ωrarr γπ0)

M2

(1 +

2m2micro

M2

)radicradicradicradic(1minus 4m2micro

M2

)

times(1 + M2

m2ω minusm2

π0

)2

minus 4m2ωM

2

(m2ω minusm2

π0)2

32 ∣∣∣Fω (M2)∣∣∣2

(42)

dΓ (ηprime rarr micromicroγ)dM = 2M 2

3α

π

Γ (ηprime rarr γγ)M2

(1minus M2

m2ηprime

)3 (1 +

2m2micro

M2

)

timesradicradicradicradic(1minus 4m2

micro

M2

) ∣∣∣Fηprime (M2)∣∣∣2

(43)

where the π0 η ω and ηprime pole masses are taken from the PDG tables [4] and the formfactors are expressed by the pole-parametrization for the η and ω mesons and from aBreit-Wigner form for the ηprime meson∣∣∣Fη (M2

)∣∣∣2 = 1(1minus M2

Λ2η

)2 (44)

∣∣∣Fω (M2)∣∣∣2 = 1(

1minus M2

Λ2ω

)2 (45)

∣∣∣Fηprime (M2)∣∣∣2 = m4

0

(m20 minusM2)2 +m2

0Γ20 (46)

For the η andω form factors the corresponding Λ parameter is taken from a recent analysison p-A NA60 data [83] while for the ηprime form factor the parameters m0 = 0764 GeVc2

and Γ0 = 0102 GeVc2 are extracted from a fit on the Lepton-G data [84] The invariantmass distributions Equations (41) to (43) are implemented in the description of theDalitz decays in the AliGenMUONLMR generator together with the definition of the formfactors Equations (44) to (46) This allows one to extract a properly distributed value ofthe virtual photon invariant mass to be used to simulate the decays ηrarr γlowastγ ωrarr γlowastγ

and ηprime rarr γlowastγ from here the full kinematics of the virtual photon can be extractedallowing in turn the kinematics of the muon pair to be evaluated

41 Light-Meson Decays 57

Figure 42 shows the generated dimuon mass distribution for the three Dalitz decaysof interest here The ηprime mass distribution (figure 42c) shows a characteristic enhancementcorresponding to the ρω peak given by the transition form factor which can be easilyinterpreted in terms of the Vector Meson Dominance model [84] For each decay the pTand y dependence of the product of geometrical acceptance and reconstruction efficiency(A times ε) is shown in figure 43 As expected the phase space coverage at low-pT is moreimportant for the Dalitz decays allowing for larger values of the dimuon invariant massFor the ηrarr micro+microminusγ decay which is the reference process for the extraction of the η-mesonsignal (Atimes ε)micro+microminus is negligible for pT

micromicro 05 GeVc putting a strong constraint in theavailable phase space for the η-meson measurement

Figure 44 shows the reconstructed dimuon mass distribution for each Dalitz decayintegrated over minus400 lt y lt minus250 and 00 lt pT lt 100 GeVc These shapes enter asingredients in the hadronic cocktail fit (discussed in section 52) imposing their profiles tobe sufficiently smooth for each phase space interval considered in the analysis since theseshapes extend over a large mass range and are not easily parameterizable a significantlylarge MC statistics is needed especially when (Atimes ε)micro+microminus is particularly low

413 Two-Body DecaysThe two-body decays of interest for the present thesis work are listed in table 43 withthe corresponding branching ratios For the ω rarr micro+microminus and φ rarr micro+microminus decays thebranching ratios are taken as the average (weighted by the corresponding uncertainty) ofthe available measurements of BR(micro+microminus) and BR(e+eminus) assuming lepton universality inorder to reduce the final uncertainty

Process Branching Ratio (BR)ηrarr micro+microminus (58plusmn 08) middot 10minus6

ρrarr micro+microminus (455plusmn 028) middot 10minus5

aωrarr micro+microminus (728plusmn 014) middot 10minus5

bφrarr micro+microminus (2954plusmn 0030)middot 10minus4

a The value reported in this table for the ω is the weighted average measurement of BR(ωrarr l+lminus)The BR(micro+microminus) is (90plusmn 31) middot 10minus5

b The value reported in this table for the φ is the weighted average measurement of BR(φ rarr l+lminus)The BR(micro+microminus) is (287plusmn 019) middot 10minus4

Table 43 Two-body decay processes in the LMR and the branching ratios used in the analysis

The decay of the vector mesons ρ ω and φ into two muons is mediated by a virtualphoton V rarr γlowast rarr micro+microminus (see figures 45b to 45d) The decay of the pseudo-scalar ηmeson into two muons is a 4th order electromagnetic process (see figure 45a) mediatedby two virtual photons where the micro+ coming from one γlowast and the microminus coming from theother γlowast are contracted

The two-body decays are implemented in the AliGenMUONLMR generator approximatingthe narrow mass line shapes of the η ω and φ mesons with a Dirac delta distributiondefined at the resonance pole mass since their physical widths are negligible with respect

58 Chapter 4 Monte Carlo Simulations

η

γlowast

microminus

γlowast

micro+

1(a) ηrarr micro+microminus

ργlowast

microminus

micro+

1(b) ρrarr micro+microminus

ωγlowast

microminus

micro+

1(c) ωrarr micro+microminus

φγlowast

microminus

micro+

1(d) φrarr micro+microminus

Figure 45 Feynman diagrams of two-body decays of the light neutral meson η ρ ω and φ

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

1

2

3

4

5

610times (gen)-micro+micro rarr ρ

Figure 46 Generated mass distribution for the ρrarr micro+microminus process see equation (47)

to the detector mass resolution On the contrary for the ρ meson due to its natural largemass distribution the following parametrization is used [8385]

dNdM =

α2m4ρ

3 (2π)4

radic1minus 4m2

micro

M2

(1 + 2m2

micro

M2

) (1minus 4m2

π

M2

)32

(m2ρ minusM2

)2+m2

ρΓ2ρ(M)

(2πMT )32 eminusMTρ (47)

with a mass-dependent width

Γρ(M) = Γ0ρmρ

M

M2

4 minusm2micro

m2ρ

4 minusm2micro

32

= Γ0ρmρ

M

(q

q0

)3

(48)

where the Γ0ρ is the full resonance width and mρ the resonance mass pole taken from [4]This distribution is shown in figure 46 one can appreciate the peculiar profile of this lineshape covering practically the whole LMR

For each decay the pT and y dependence of Atimes ε is shown in figure 47 As expectedthe phase space coverage at low-pT becomes larger as the mass of the meson increases

41 Light-Meson Decays 59

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrη for -micro+micro)ε times(A

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrρ for -micro+micro)ε times(A

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrω for -micro+micro)ε times(A

]c [GeVT

p0 2 4 6 8 10

y4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrφ for -micro+micro)ε times(A

Figure 47 Acceptance times efficiency of two body decay

(a) ηrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1

- micro+ micro

MdN

d

0

005

01

015610times (rec)-micro+micro rarr η

(b) ωrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

01

02

03

04

610times (rec)-micro+micro rarr ω

(c) ρrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

002

004

006

008

01

012

610times (rec)-micro+micro rarr ρ

(d) φrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

01

02

03

04

610times (rec)-micro+micro rarr φ

Figure 48 Reconstructed dimuon mass distribution of two body decays integrated in full phasespace

60 Chapter 4 Monte Carlo Simulations

For the ω rarr micro+microminus decay which is the reference process for the extraction of the ω-meson signal (Atimes ε)micro+microminus is significant down to pT = 00 GeVc in the rapidity rangeminus400 lt y lt minus325 and down to pT asymp 20 GeVc towards the y = minus250 limitFor the φ rarr micro+microminus decay from which φ-meson signal can be extracted (Atimes ε)micro+microminus issignificant down to pT = 00 GeVc in the rapidity range minus400 lt y lt minus300 and downto pT asymp 20 GeVc towards the y = minus250 limit

Figure 48 shows the reconstructed dimuon mass distribution for each two-body decayintegrated over minus400 lt y lt minus250 and 00 lt pT lt 100 GeVc These shapes enter to-gether with the Dalitz one discussed in the previous section as ingredients in the hadroniccocktail fit From the mass distributions in figure 48 the detector mass resolution for thenarrow η ω and φ mesons can be estimated performing a Gaussian fit on the centralpart of the peaks the value are found to be ση asymp 458 MeVc2 σω asymp 489 MeVc2 andσφ asymp 520 MeVc2

42 Dimuons from Open Heavy-Flavor DecaysIn the low mass region in addition to the Dalitz and two-body decays of light neutralmesons two other processes may contribute namely the so-called open charm and openbeauty processes In these processes a correlated muon pair comes from the simultaneoussemi-muonic decay of two correlated heavy-flavor hadrons coming from the hadronizationof a heavy qq pair These processes are illustrated in figure 49 for the open charm andbeauty

c

DX

micro

c

D

micro

X

b

BX

micro

b

B

micro

X

Figure 49 Illustration of open heavy-flavor decays

The open charm and beauty processes are generated with the PYTHIA6 MC gener-ator PYTHIA generates the primary cc (or bb) quark pairs performs the correspondinghadronization as well as the decay of the heavy flavor hadrons The decays of the long-livedparticles possibly appearing in the decay chains of the heavy-flavor hadrons are performedby the transport code GEANT3 To save CPU time the PYTHIA6-based parametric gener-ator (AliGenCorrHF) is used developed within the AliRoot framework generating oneheavy-flavor pair per event to further optimize the simulation the first heavy hadronpair is produced in the rapidity hemisphere of the muon spectrometer

The simulation of the open charm and beauty processes depends of the knowledgeof the kinematic distributions of the primary cc (or bb) quark pairs determining the

42 Dimuons from Open Heavy-Flavor Decays 61

kinematics of the first hadron pair and thus the shape of the mass distribution of finalmuon pairs The cc and bb kinematic distributions are known with large uncertainties atforward rapidity at the LHC energies due to the lack of measurements of heavy flavorhadrons in this kinematic range For this reason we also considered a second modelFONLL [86] (for Fixed-Order plus Next-to-Leading Log) giving an alternative descriptionof the cc and bb kinematic distributions based on some perturbative calculation madepossible by the large mass of the charm and beauty quarks To optimize the CPU timefor the simulations based on the FONLL predictions a reweighting is applied on the ex-isting simulations based on the ratio between the (pT minus y) parton distributions given byPYTHIA and FONLL The reweighting has been performed considering three FONLL kinemat-ics distributions the central prediction the prediction corresponding to the upper limitassociated to the uncertainty range and the prediction corresponding to the lower limitassociated to the uncertainty range in this way we can compare up to four hypothesesfor the input of the open charm and beauty processes

The discussion presented in the following section applies to the open charm processas well as to the open beauty one similarly each figure will include two panels the ldquoardquoone dedicated for the open charm case the ldquobrdquo for the beauty case

421 PYTHIAndash FONLL ComparisonTo estimate the difference between the available hypotheses on the input parton kinemat-ics the ratio of the FONLL partonic pT distributions (corresponding to the central valueand the upper-lower limits of the uncertainty range) to the PYTHIA one is shown in Fig-ure 410 In this figure the ratio corresponding to FONLL central value is represented insolid curve and the ratios corresponding to the upper and lower limits of FONLL uncertaintyrange are represented as an uncertainty band As can one see the ratio of the centralFONLL value to PYTHIA deviates significantly from unity the deviation becomes strongerwhen the upper-lower limits of the FONLL prediction are considered The PYTHIA-FONLLdisagreement is stronger for the charm than for the beauty

It is now interesting to investigate how the difference between the PYTHIA and FONLLpredictions for the input kinematic distributions of the cc and bb quark pairs affects theshape of the reconstructed dimuon mass spectra which will be used as ingredients ofthe fit of the data To do so the reconstructed mass spectra corresponding to the fouravailable MC inputs are compared in figure 411 PYTHIA FONLL central value FONLLupper value and FONLL lower value For the sake of comparison the four distributionsare normalized to the same integral In the case of the open charm process figure 411athe differences between the models are clearly visible accross the considered mass rangewhile for the open beauty process figure 411b there is a remarkable agreement betweenthe curves A possible way to quantify the uncertainty on reconstructed dimuon massdistributions of open charm and beauty due to the model assumed for the input partonicdistribution is to evaluate the FONLL over PYTHIA ratios as a function of the dimuon massas shown in figure 412

As expected the ratios for the open beauty process stay significantly closer to unitythan the open charm process By inspecting the graphs one can estimate the uncertaintyon the open charm shape to be of the order of 15 in the LMR significantly increasing

62 Chapter 4 Monte Carlo Simulations

]c [GeVT

p0 2 4 6 8 10

ratio

FO

NLL

Pyh

tia fr

om C

harm

0

1

2

3

(a) charm

]c [GeVT

p0 2 4 6 8 10

ratio

FO

NLL

Pyh

tia fr

om B

eaut

y

0

1

2

3

(b) beauty

Figure 410 Partonic pT distribution ratio FONLL [87] over PYTHIA the black curve represents thereference value of the ratio and the red hatching represents the error according to FONLL model

]2c [GeV-micro+microM0 1 2 3 4 5

au

0

10

20

30

40

50

3minus10times

FONLL

PYTHIA

FONLL - max

FONLL - min

(a) open charm

]2c [GeV-micro+microM0 1 2 3 4 5

au

0

10

20

30

40

3minus10timesFONLL

PYTHIA

FONLL - max

FONLL - min

(b) open beauty

Figure 411 Reconstructed dimuon mass coming from open heavy flavor semi-leptonic decays

towards large masses while from the open beauty shape the uncertainty in the LMR stayswithin 5 We will come back to these uncertainties in section 52 where the fit routineallowing the signal extraction will be discussed

422 Decay Chain Length in the Open Heavy-Flavor Processes

In the open heavy-flavor processes considered in this section the number of decay stepsbetween the initial parton and the final muon (noted decay chain afterwards) can bepotentially large resulting in a weakening of the kinematic correlation between the initialand the final states If the decay chains associated to the two final muons are sufficiently

42 Dimuons from Open Heavy-Flavor Decays 63

]2c [GeV-micro+microM0 1 2 3 4 5

0

02

04

06

08

1

12

14

FONLL over Pythia

FONLL - Min over Pythia

FONLL - Max over Pythia

(a) open charm

]2c [GeV-micro+microM0 1 2 3 4 5

09

095

1

105

FONLL over Pythia

FONLL - Min over Pythia

FONLL - Max over Pythia

(b) open beauty

Figure 412 Dimuon mass spectrum ratio from FONLL (reference min and max value) over PYTHIA

long the initial qq correlation could be substantially washed out in the final muon pairFor this reason it is interesting to study the distribution of the decay chain length (λmicro)in simulated open charm and beauty processes defined as the number of decay stepsbetween the initial parton and the final muon

-microlength 0 2 4 6 8 10

+ microle

ngth

0

2

4

6

8

10

1

10

210

310

410

510

(a) open charm

-microlength 0 2 4 6 8 10

+ microle

ngth

0

2

4

6

8

10

1

10

210

310

410

510

(b) open beauty

Figure 413 micro-chain for open heavy flavor at generated level

In figure 413 the correlation between the λmicro of the positive and negative muons isshown for the dimuons coming from the open charm and beauty simulations In thisfigure on can clearly see that λmicro can get as large as 10 As expected the average λmicrovalues are larger for the open beauty process than the open charm one due to the largerphase space available

Since the λmicro distributions extend over relatively large ranges one can wonder which isthe impact of having short or long muon decay chains on the shape of the dimuon invariant

64 Chapter 4 Monte Carlo Simulations

]2c [GeV-micro+microM0 1 2 3 4 5

au

4minus10

3minus10

2minus10

1minus10

4le plusmnmicroλ = 4 amp plusmnmicroλ 3le plusmnmicroλ = 3 amp plusmnmicroλ 2le plusmnmicroλ = 2 amp plusmnmicroλ 1le plusmnmicroλ = 1 amp plusmnmicroλ

(a) open charm

]2 [GeVc-micro+microM0 1 2 3 4 5

au

4minus10

3minus10

2minus10

1minus10

4le plusmnmicroλ = 4 amp plusmnmicroλ 3le plusmnmicroλ = 3 amp plusmnmicroλ 2le plusmnmicroλ = 2 amp plusmnmicroλ 1le plusmnmicroλ = 1 amp plusmnmicroλ

(b) open beauty

Figure 414 Generated dimuon mass coming from open heavy flavor semi-leptonic decays withparticular λmicro

mass distributions To do so in figure 414 the dimuon mass distributions are shown forfour particular λmicro+λmicrominus combinations As expected shorter decay chains correspond toharder mass distributions

We thus verified that the shape of the invariant mass profile of the open charm andbeauty dimuons depends of the length of the decay chains of the two muons This meansthat to properly reproduce the dimuon mass profile of the open charm and beauty com-ponents in the data we have to correctly reproduce the distribution of the decay lengthchains for the simulated dimuons Now this is not a problem as long as any dimuon froman open charm or beauty process is retained both in the data and in the MC Howeverthe data considered for the signal extraction are obtained by subtracting the combinato-rial background from the raw dimuon spectrum implying that we should retain in theMC the correlated dimuons only But the correlation of a muon pair coming from anopen charm or beauty process is progressively lost as the length of the decay chains of thetwo muons increases and it is extremely hard mdash in terms of analysis strategy and CPUtime mdash to estimate and take such an effect into account in the MC simulations Thisintroduces a source of uncertainty when describing the correlated continuum in the datawith the superposition of the open charm and beauty simulations

Chapter 5

Signal Extraction

Summary51 Combinatorial Background Evaluation and Subtraction 65

511 The Event Mixing Technique 66

512 Monte Carlo Validation of the Event Mixing Technique 67

513 The Combinatorial Background Estimation 68

52 Invariant Mass Fit Procedure 70

521 Specific Constraints on the Hadronic Cocktail Components 71

522 Correlated Continuum Treatment 72

523 A Few Examples of Hadronic Cocktail Fits 76

In this chapter the main source of background for the dimuon decay channel will bediscussed as well as the strategy considered for the extraction of the signals of interestFrom now on following a convention widely used within the ALICE muon communityrapidity values are given in the positive axis justified by the symmetry of the pp collisionsystem with respect to y = 0

51 Combinatorial Background Evaluation and Sub-traction

The present analysis is based on the study of the OS dimuon invariant mass spectrumDimuons are built by combining muon pairs coming from the same event (see section 31)Since dimuons coming from the light-neutral meson decays of interest for this work cannotbe disentangled from the other dimuon sources any pair of muons must be consideredwhen building the dimuon invariant mass spectrum This implies that a fraction of theconsidered dimuons actually comes from randomly paired uncorrelated muons this frac-tion of dimuons is conventionally named ldquocombinatorial backgroundrdquo The ratio betweenthe correlated and uncorrelated dimuon components varies significantly according to thecollision system the considered mass region and the apparatus performance In the low-mass region the ALICE muon spectrometer gives correlated over uncorrelated dimuonratios as large as few units (in pp collisions) and as low as few percents (in the mostcentral Pb-Pb collisions)

66 Chapter 5 Signal Extraction

511 The Event Mixing TechniqueThe combinatorial background for the OS dimuons has been evaluated using an eventmixing technique based on the reasonable assumption that the LS dimuon sample doesnot contain correlated muon pairs The mixing event technique implies the creation of asample of uncorrelated dimuon formed by pairing two muons coming from two differentevents In the following we will identify dimuons built from a same event with the labelldquodirrdquo and dimuons built from different events with the label ldquomixrdquo The event mixingtechnique is illustrated in figure 51

Event A

micro+A1

microminusA2

Event B

microminusB1

microminusB2

micro+B3

Opposite Signmicro+A1micro

minusB1

micro+A1micro

minusB2

microminusA2micro+B3

Like Sign ++micro+A1micro

+B3

Like Sign minusminusmicrominusA2micro

minusB1

microminusA2microminusB2

Figure 51 Illustration of mixing events with two events one with two muons and one with threemuons

The mixed OS dimuon sample is used in the event mixing technique to estimatethe OS combinatorial background in the direct OS dimuon sample for this reason onlyevents sharing same global properties are considered in the event mixing Among theseglobal properties one can cite the z-position of the primary vertex the charged-particlemultiplicity or in nucleus-nucleus collisions the orientation of the event plane In the ppcollisions considered in the present analysis the impact of classifying the events accordingto the z-position of the primary vertex and the charged-particle multiplicity was testedresulting in no difference with respect to the case in which the events are mixed regardlessof their global properties1

The shape of the invariant mass distribution expected for the OS uncorrelated dimuonsis taken for each kinematic range considered in the analysis directly from the outputdistribution Nmix

+minus (M) given by the event mixing technique The normalization is fixed tothe integral of the distribution 2R(M)

radicNdir

++(M) middotNdirminusminus(M) extracted from the data

Nmix+minus (M) minusrarr Nmix

+minus (M)

int2R(M)

radicNdir

++(M) middotNdirminusminus(M) dMint

Nmix+minus (M) dM

(51)

The integral of the 2R(M)radicNdir

++(M) middotNdirminusminus(M) distribution is indeed a good estimation

of the total number of the OS dimuons in the data as long as the LS dimuon samples1 This is valid as long as the analysis is integrated over the mentioned global properties in particular

the charged-particle multiplicity

51 Combinatorial Background Evaluation and Subtraction 67

Ndir++ and Ndir

minusminus do not contain any correlated muon pair The R factor accounts for thepossible differences between the acceptances of ++ minusminus and +minus muon pairs

R(M) = A+minus(M)2radicA++(M) middotAminusminus(M)

(52)

The R factor was estimated as

R(M) = Nmix+minus (M)

2radicNmix

++ (M) middotNmixminusminus (M)

(53)

where Nmix++ and Nmix

minusminus is the number of dimuons for the given sign combination theacceptances are evaluated with the mixing

512 Monte Carlo Validation of the Event Mixing TechniqueA Monte Carlo approach was considered to check the quality of the combinatorial back-ground estimation as follows Events containing two muons were simulated with thekinematics extracted randomly and independently for the two muons from some pT andy distributions taken from the data The azimuthal angle of each muon was randomlydrawn within flat distribution and the charges also randomly attributed In this waythe OS sample of the direct dimuons from this MC event sample could be assumed to bepurely combinatorial by construction We could thus check if the procedure describedabove was able to reproduce its mass shape and normalisation To do this we appliedto this same MC sample the event mixing technique to obtain the mass shape with thecorrect normalization

The ratio RMCdirmix between the true and estimated mass shapes of the combinatorial

OS dimuons was thus extracted for each kinematics interval considered in the analysisSeveral options are possible for the trigger class of the events considered in the eventmixing procedure The considered trigger classes are based on the ldquoV0rdquo trigger conditionsee section 31 to which a specific condition is added based on the response of the muontrigger

bull ldquoMULrdquo based on the presence of at least two tracklets in the muon trigger systemof opposite sign both passing the low-pT single-muon threshold

bull ldquoMLLrdquo based on the presence of at least two tracklets in the muon trigger systemof like sign both passing the low-pT single-muon threshold

bull ldquoMSLrdquo based on the presence of at least one tracklet in the muon trigger systempassing the low-pT single-muon threshold

bull ldquoMSL-onlyrdquo it is defined by this logical combination of trigger conditionsMSL ampMUL ampMLL so it is the condition which minimizes the impact of the dimuontrigger condition on the retained events

The trigger condition of the events considered for the event mixing technique waschosen as the one maximizing the flatness of RMC

dirmix Figures 52 and 53 show that the

68 Chapter 5 Signal Extraction

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeVmicromicroM

0 1 2 3 4 5 6

Dir

ect

Mix

ed

06

08

1

12

14

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

lt 40y25 lt

c lt 100 GeVT

p00 lt = 13 TeVsALICE pp

MUL

MLL

MSL

Figure 52 Comparison of background evalua-tion ratio direct over mixed for ldquoMULrdquo ldquoMLLrdquoand ldquoMSLrdquo conditions

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeVmicromicroM

0 05 1 15 2 25 3

Dir

ect

Mix

ed

09

095

1

105

11

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

MSL

MSL amp MUL amp MLL

Figure 53 Comparison of background evalu-ation ratio direct over mixed for ldquoMSLrdquo andldquoMSL-onlyrdquo conditions

best results are obtained considering events satisfying the ldquoMSL-onlyrdquo condition withldquoMSLrdquo condition also giving a reasonably small deviation of RMC

dirmix from unity On thecontrary the worst performance is associated to the MLL and MUL trigger conditions

The combinatorial background mass shape evaluated for the real data was correctedfor the RMC

dirmix ratio To get rid of the statistical fluctuations due to the limited availableMC sample this ratio is parametrized by the following function before being used tocorrect the data

f(M) = A eminusaM minusB eminusbM +C (54)

where all the parameters are imposed to be positive except C This correction is performedindependently in each (pT y) phase space interval considered in the analysis

513 The Combinatorial Background Estimation

Having validated the method for the evaluation of the combinatorial background it is nowpossible to use it for isolating the dimuon correlated signal in the data Following the resultof the MC validated presented in the previous section the ldquoMSL-onlyrdquo events are used asinput for the event mixing technique The typical mass dependence of the R-factor (ratiobetween the acceptance of LS and OS muon pairs) defined in equation (52) and estimatedas equation (53) is shown in figure 54 for the phase space interval 10 lt pT lt 100 GeVcand minus400 lt y lt minus250 In this same kinematics interval the comparison between theraw dimuon and the combinatorial background is shown in figure 55 The correspondingisolated dimuon correlated signal is shown in figure 56 forMmicromicro lt 100 GeVc2 where thepeaks of the Υ(1S) ψ(2S) and Jψ resonances can be observed and in figure 57 for thelow-mass region where the peaks of the φ and ρω two-body decays are visible togetherwith the structure of the η Dalitz decay

51 Combinatorial Background Evaluation and Subtraction 69

]2c [GeVmicromicroM0 2 4 6 8 10

R

0

02

04

06

08

1

12

lt 1000T

p100 lt

lt - 250y- 400 lt

B TeyssierWork Thesis

Figure 54 The R factor for the data integratedin 10 lt pT lt 100 GeVcand minus400 lt y lt minus250

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 2 4 6 8 10

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

dNd

M

210

310

410

510

610

raw mass spectrum

mass spectrummixOS

B TeyssierWork Thesis

Figure 55 Raw data between 250 lt y lt 400and 10 lt pT lt 100 GeVc

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeVmicromicroM0 2 4 6 8 10

]2 c [d

imuo

ns p

er 2

5 M

eV

micromicrodN

dM

210

310

410

510

610 B TeyssierWork Thesis

Jψ

ψ (2S)

Υ (1S)

Figure 56 Signal after subtraction of combina-torial background in mass range between 02 to100 GeVc2

0 02 04 06 08 1 12 140

01

02

03

04

05

610timesB Teyssier

Work Thesis

ρω

φ

Figure 57 Signal after subtraction of combina-torial background in mass range between 02 to15 GeVc2

70 Chapter 5 Signal Extraction

The combinatorial background estimation and subtraction is particularly challengingat very low pT where the signal-over-background ratio is smaller (as small as asymp 1 at theφ peak) In order to appreciate how the signal can nevertheless be extracted down tovery low pT in figure 58 (top panels) the raw data with the associated combinatorialbackground are shown for 00 lt pT lt 02 GeVc in the rapidity intervals where theacceptance is non-negligible (the most forward region see figures 43 and 47) Thecorresponding isolated signal is shown in the same figure (bottom panels)

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

25310times

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 375 lt y lt 400

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15310times

B TeyssierWork Thesis

(e) 350 lt y lt 375

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310timesB Teyssier

Work Thesis

(f) 375 lt y lt 400

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310timesB Teyssier

Work Thesis

Figure 58 Rapidity evolution of signal and combinatorial background shapes for 00 lt pT lt

02 GeVc

52 Invariant Mass Fit ProcedureAfter subtraction of the uncorrelated background the next step in the analysis is theextraction of the signals of interest from the dimuon correlated invariant mass spectrumin this specific case this means counting how many dimuons from the η rarr micro+microminusγω rarr micro+microminus and φ rarr micro+microminus decays can be extracted from the data for each of the pT-yintervals considered in the analysis For this step the dimuon correlated invariant massspectrum is decomposed into the expected sources composing the hadronic cocktail (two-body and Dalitz decays of light neutral mesons see section 41) via a fit procedure also

52 Invariant Mass Fit Procedure 71

including a description of the correlated continuum component

521 Specific Constraints on the Hadronic Cocktail Compo-nents

In the fit procedure considered in this analysis for the extraction of the signals of interestspecific constraints have been imposed to the components of the hadronic cocktail inorder to reduce the number of degrees of freedom fixing the minor processes (in terms ofreconstructed dimuons) to the major ones Each considered constraint has been also takenas a contribution in the evaluation of the systematics on the signal extraction discussedin section 61

Fixing the relative branching ratios of two-body and Dalitz decays for the ηand ω meson mdash The η and ω mesons contribute to the hadronic cocktail with twodecay channels ηrarr micro+microminusγ and ηrarr micro+microminus for the η and ωrarr micro+microminusπ0 and ωrarr micro+microminus

for the ω Since the branching ratios of each channel is known from the literature thenormalizations of the two-body and Dalitz decay modes can be fixed to each other (as longas the quality of the data does not allow for an independent measurement of the relativebranching ratios) This constraint has been technically implemented for the η meson byconsidering the normalization of the ηrarr micro+microminusγ process has a free parameter and fixingthe ηrarr micro+microminus contribution to it for the ω meson the normalization of the ωrarr micro+microminus

process has been left as a free parameter the contribution of the ω rarr micro+microminusπ0 decaybeing fixed to it For each particle the process associated to the free parameter is the onemore clearly identifiable in the invariant mass profile of the data The relevant branchingratios are listed in tables 42 and 43

Fixing the σηprimeσφ cross-section ratio mdash The contribution of the ηprime Dalitz decayaccounts for a very small fraction of the total reconstructed dimuon mass spectrum forthis reason and because of its continuum shape having no dominant structure apart fromthe broad peak at ρ mass (due to the contribution of the ρ meson to the ηprime form factorsee section 412) the fit procedure is not sensitive to this contribution Consequently thenormalization of the ηprime rarr micro+microminusγ process has been set by fixing the ηprime cross-section tothe cross-section of one of the particles giving a major contribution to the invariant massspectrum namely the φ meson The reference value for the σηprimeσφ cross-section ratio hasbeen evaluated with PHOJET to be 3151 in the rapidity window 25 lt y lt 40 integratedover pT This ratio has been rescaled in each pT-y interval considered in the analysisaccording to the kinematic distributions of the two particles also given by PHOJET

Fixing the σρσω cross-section ratio mdash Due to the broad line shape of the ρ mesonand the limited mass resolution of the detector for the superimposed ω rarr micro+microminus peakthe ρ rarr micro+microminus contribution cannot be easily disentangled in the fit procedure For thisreason the normalization of the ρrarr micro+microminus contribution has been set to the ωrarr micro+microminus

one by fixing the σρσω cross-section ratio The reference value for this ratio has beentaken as 10 from previous measurements [88ndash90]

72 Chapter 5 Signal Extraction

Due to the mass resolution of the ω peak the distinction of the ω and ρ two-bodycontribution is not obvious So it is better to enslave the ρ two-body component to theω to increase the stability of the fit The ratio of the production cross-section of ρω ismeasured to 10 in several previous experiments [88ndash90]

522 Correlated Continuum TreatmentSeveral choices can be considered for the description of the correlated continuum as dis-cussed below As discussed in section 42 the main sources in the correlated dimuoncontinuum are the open charm and beauty processes However as also discussed in sec-tion 42 the evaluation of the MC template of the invariant mass shape of the open charmand beauty dimuons is affected by potentially non-negligible uncertainties according tothe considered input for the cc and bb kinematics and the real degree of correlation of thefinal state muons Moreover one as to consider the possibility of having some residualuncertainty from the combinatorial background subtraction and a possible dimuon com-ponent from correlated light-flavor hadron decays On the basis of these considerationstwo approaches have been tested for the description of the correlated continuum

In the fit process for treating the underlying physics continuum we assume that themain source of this continuum is based on the open heavy-flavor where the way to obtainthe shapes of open charm and beauty are described in section 42 Two possible ways forusing these shapes in the fit process one based on the full description of all processes theother based on a phenomenological approach for the correlated continuum and realisticdescription of processes are considered

The ldquocharm+beautyrdquo approach mdash This approach is based on three assumptions

1 The correlated continuum has only two components open charm and beauty

2 The shapes of the dimuon invariant mass templates for the open charm and beautyprocesses are known with negligible uncertainties (with the same precision as thetemplates for the hadronic cocktail processes)

3 The ratio between the open beauty and the open charm dimuon components isknown (together with its pT and y dependence at the specific energy considered inthe analysis) either from measurements or from tuned models like FONLL or PYTHIA

In this approach the correlated continuum description is associated to one free parameterThe only available measurements for the cc and bb cross-section at forward rapidity comefrom LHCb [3891ndash93] the ratio σbbσcc is (594plusmn 055) middot 10minus2 in good agreement withthe central value of the FONLL prediction (645 middot 10minus2) [86 87]

When considering this approach in the description of the correlated continuum non-negligible tensions between data and MC can be found according to the specific phasespace interval considered These tensions increase towards mid-rapidity while are almostnegligible for the most forward rapidity intervals An example is given in the left-columnplots of figures 59 and 510 where the data-MC comparison is shown for the six y intervals

52 Invariant Mass Fit Procedure 73

considered for the analysis in the pT interval 20 lt pT lt 22 GeVc The same trend isobserved in almost all the considered pT intervals

As a matter of fact these tensions induce an indirect bias on the extraction ofthe signals of interest for the analysis particularly important for the extraction of theω rarr micro+microminus signal For this reason this approach is probably not well-fitted for thisspecific analysis aiming to simultaneously extract the η rarr micro+microminusγ ω rarr micro+microminus andφrarr micro+microminus signals

The semi-empirical approach mdash This new approach has been developed after con-sidering the major limitations of the ldquocharm+beautyrdquo approach in describing the dataover the full rapidity interval available The main difference with respect to the previousapproach is the fact that we abandon any strict physical interpretation of the correlatedcontinuum describing it with an empirical profile flexible enough to saturate the tensionbetween data and MC ensuring a robust extraction of the signals of interest for the anal-ysis This is achieved by describing the correlated continuum by means of two (or more)free parameters each controlling the normalization of an independent empirical shapeThe specific shape of these independent components is not really important still one hasto use sufficiently different mass shapes to ensure enough freedom on the total profile ofthe continuum

Two variants of this semi-empirical approach have been tested in this analysis

bull A 2-component description of the correlated continuum In this case an obviouschoice is to take the two components as the invariant mass distributions of OSdimuons from open charm and open beauty simulations2 This choice allows one tocombine the required smoothness of the continuum invariant mass shape with thekinematical constraints typical of a reconstructed dimuon mass distribution closeto the low-mass threshold this would not have been (easily) achievable with anytrivial combination of analytical parametric functions

bull A 3-component description of the correlated continuum In this variant we add athird component to the two components already considered in the previous case areasonable choice is to take this third component to have the profile of the combi-natorial background evaluated in each pT and y interval considered in the analysis

The results of the data description with these two variants of the semi-empirical ap-proach are shown in figures 59 and 510 in the center and right panels respectively forthe 2- and the 3-component description of the correlated continuum As one can see the2-component description already fixes the tension between data and MC found with theldquocharm+beautyrdquo approach in the full y range Nevertheless the addition of the third de-gree of freedom allowed by the 3-component description of the correlated continuum stillimproves the extraction of the signal in some specific cases see for instance the extractionof the φrarr micro+microminus signal in figures 59b and 59c For this reason the 3-component variantof the semi-empirical approach has been retained as the reference method for the signalextraction for the present analysis

2 It should be clear that in this semi-empirical approach the physical interpretation of any of the twocomponents taken separately is meaningless and must be avoided

74 Chapter 5 Signal Extraction

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 275y250 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 275y250 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 275y250 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 300y275 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 300y275 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 300y275 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(g) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(h) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(i) 300 lt y lt 325

Figure 59 Signal fit for 20 lt pT lt 22 GeVc and various y intervals The first figure of each linecorresponding to the method with the full description of processes the second and third figures ofeach line corresponding to the hybrid method with two or three components respectively

52 Invariant Mass Fit Procedure 75

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6310times

lt 400y375 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(g) 375 lt y lt 400

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6310times

lt 400y375 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(h) 375 lt y lt 400

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6310times

lt 400y375 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(i) 375 lt y lt 400

Figure 510 Signal fit for 20 lt pT lt 22 GeVc and various y intervals The first figure of eachline corresponding to the method with the full description of processes the second and third figuresof each line corresponding to the hybrid method with two or three components respectively

76 Chapter 5 Signal Extraction

523 A Few Examples of Hadronic Cocktail FitsThe detailed breakdown of the MC sources involved in the fit procedure is shown infigure 511 where the data sample considered in the present analysis is integrated over250 lt y lt 400 and 10 lt pT lt 100 GeVc The structures of the η rarr micro+microminusγω rarr micro+microminus and φ rarr micro+microminus processes considered for the estimation of the η ω and φyields are observed to shine out over the underlying continuum Here as well as in thefits presented in the rest of the document the red profile is the sum of the MC sourcesThe uncertainty on the total MC profile is evaluated by combining the uncertainties onthe normalization of each considered source For the processes whose normalization isleft free in the fit this uncertainty is the statistical one resulting from the fit procedureitself for the other processes we propagate the systematic uncertainty on the parameters(branching ratios or cross section ratios) which fix their normalizations to those of thefree processes

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

01

02

03

04

05

610times

γmicromicro

rarrη

γmicromicrorarrη

micromicrorarrη

micromicrorarrρ0πmicromicrorarrω

micromicrorarr

ω

micromicrorarrφ

continuumcorrelated

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

lt 400y250 lt

c lt 1000 GeVT

p100 lt = 13 TeVsALICE pp

lt 40y25 lt

c lt 100 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y250 lt

c lt 1000 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 40y25 lt

c lt 100 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y250 lt

c lt 1000 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

Figure 511 Example of hadronic fit in 250 lt y lt 400 and 10 lt pT lt 100 GeVc

The shape of the dimuon invariant mass spectrum changes significantly according tothe considered pT-y interval In particular at very low-pT and towards central rapiditythe acceptance constraints imposed by the detector deplete the mass spectrum near thekinematic threshold For this reason some of the processes are not measurable in specificregions of the phase space as it could be expected by inspecting the pT-y profiles of the(Atimes ε) reported in figures 43 and 47 In addition at high-pT one observes a decrease ofthe ratio of the hadronic cocktail over the correlated continuum which could be attributedto the decrease of the ratio of the light flavor sources (composing the hadronic cocktail)over the heavy flavor ones (contributing to the correlated continuum) The full evolutionof the dimuon invariant mass spectrum profile as a function of pT and y can be appreciated

52 Invariant Mass Fit Procedure 77

by considering the plots in appendix C In figure 512 we report a few examples illustratingthe discussed point

(a) 00 lt pT lt 02 GeVcand 375 lt y lt 400

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 04 lt pT lt 05 GeVcand 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 20 lt pT lt 22 GeVcand 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

310times

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 40 lt pT lt 45 GeVcand 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 70 lt pT lt 80 GeVcand 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 80 lt pT lt 100 GeVcand 250 lt y lt 275

Figure 512 A few examples of hadronic fit in several pT and y intervals

Chapter 6

Systematics Evaluation

Summary61 Systematics on the Signal Extraction 80

611 Relative Branching Ratio of two-body and Dalitz Decays for the ηand ω Mesons 80

612 σηprimeσφ Cross-Section Ratio 80

613 σρσω Cross-Section Ratio 81

614 Upper limit of the fit 81

615 The correlated continuum shape 81

616 Systematic Uncertainty Computation 82

62 Systematics from the MC input 82

63 Systematics on Trigger Efficiency 83

631 Evaluation of the Trigger Response Function 83

632 Results 84

64 Systematics on Tracking Efficiency 85

641 Preliminary Check 85

642 Tracking Efficiency Evaluation 86

643 MC parametrization 88

644 Results 89

65 Summary of Systematic Uncertainty 89

In this chapter all the systematics sources of the present analysis are presented Twomain groups of systematics uncertainties have been studied

bull the sources contributing to the systematics uncertainty on the signal extraction

bull the sources contributing to the systematics on the (Atimes ε) evaluation

In the first group we include the uncertainties on the parameters involved in thefit procedure (see section 52) relative branching ratios cross-section ratios correlatedcontinuum shape fit range In the second group we include the uncertainties on thekinematic input of the MC simulations on the tracking efficiency and the trigger response

80 Chapter 6 Systematics Evaluation

61 Systematics on the Signal ExtractionIn order to define the systematics tests on the signal extraction a reference scenario hasbeen defined based on the reference values of the parameters involved in the fit procedureFor each parameter one or more alternative values have been considered each systematictest is defined by the variation of one parameter only while the others are kept fixedto their reference value In total 10 systematic tests have been considered the totalsystematic uncertainty on the number of η rarr micro+microminusγ ω rarr micro+microminus and φ rarr micro+microminus

dimuons was taken as the standard deviation of the values resulting from these tests

Syst test reference value alternative value(s)BR ηrarr micro+microminus PDG PDG minus1σ PDG +1σBR ωrarr micro+microminusπ0 PDG PDG minus1σ PDG +1σRatio σηprimeση 0295 minus50 +50Ratio σρσω 10 minus10 +10Upper fit limits 15 GeVc2 20 GeVc2

Templates for thecorrelated contin-uum components

ccrarr micromicro from PYTHIAbbrarr micromicro from PYTHIA

OS from evt mix (data)

ccrarr micromicro from FONLLbbrarr micromicro from FONLL

OS from combinatorial bkg (MC)

Table 61 Summary of systematics tests

611 Relative Branching Ratio of two-body and Dalitz Decaysfor the η and ω Mesons

This systematics test reflects the uncertainty on the ratio between the branching ratio ofthe two-body and Dalitz decay channel of the η and ω mesons In this analysis this testwas implemented by varying the branching ratio of the η rarr micro+microminus and ω rarr micro+microminusπ0

processes by plusmn1σ where σ is the uncertainty on the measurement reported by the PDG(shown in tables 42 and 43) resulting in four independent alternative fits on the data

The variation of the ηrarr micro+microminus branching ratio was found to have a negligible impacton the extraction of η rarr micro+microminusγ and φ rarr micro+microminus signals and a limited impact on theextraction of the ωrarr micro+microminus signal of the order of 1 On the contrary the variation oftheωrarr micro+microminusπ0 branching ratio by plusmn1σ has an average impact of plusmn3 for the extractionof ηrarr micro+microminusγ and ωrarr micro+microminus signals and negligible for the φrarr micro+microminus signals

612 σηprimeσφ Cross-Section Ratio

The ratio σηprimeσφ was varied by plusmn50 to take into account the general lack of mea-surements for this ratio and the differences between the predictions from the availablephenomenological models PYTHIA6 and PHOJET The impact of the considered plusmn50 vari-ation has been observed to be in average ∓2 for the ωrarr micro+microminus signal and negligiblefor the φrarr micro+microminus and ηrarr micro+microminusγ signal

61 Systematics on the Signal Extraction 81

613 σρσω Cross-Section RatioThe uncertainty on the σρσω ratio has been taken from the existing measurements atlower energy [88ndash90] The absence of any strong theoretical argument in favor of animportant energy dependence of this ratio allowed us to take a plusmn10 for the associateduncertainty As expected the impact of this plusmn10 variation is non-negligible only for theextraction of theωrarr micro+microminus signal which is affected by a corresponding ∓2 uncertainty

614 Upper limit of the fitThe lower limit of the invariant mass fit range has been set to the 2mmicro kinematic thresholdin order to be sensitive to the full structure of the η rarr micro+microminusγ decay For the upperlimit a reference value has been set at 15 GeVc2 this value is a trade-off betweenbeing sensitive to the full width of the φ rarr micro+microminus peak and limiting the impact of thecontinuum region between the φ and Jψ resonance where no signal of interest for thelight-neutral mesons can be extracted To study the systematic uncertainty linked to thechoice of the upper limit of the fit range an alternative value has also been defined at20 GeVc2 The corresponding average impact on the extraction of the signals of interestis -3 -12 and -4 respectively for the η rarr micro+microminusγ ω rarr micro+microminus and φ rarr micro+microminus

signals

615 The correlated continuum shape

]2c [GeVmicromicroM0 02 04 06 08 1 12 14

[au

]micromicro

dNd

M

0

5

10

15

20

25

3minus10times

from OS mixing

(PYTHIA)bfrom b

(PYTHIA)cfrom c

(a) Reference

]2c [GeVmicromicroM0 02 04 06 08 1 12 14

[au

]micromicro

dNd

M

0

5

10

15

20

25

3minus10times

microfrom OS MC uncorr

(FONLL)cfrom c

(FONLL)bfrom b

(b) Alternative

Figure 61 Normalized shape of continuum templates

The shape of the correlated continuum is determined by the fit by optimizing therelative weight of three invariant mass templates as explained in section 522 To eval-uate the systematic uncertainty associated to the choice of this set of templates analternative set of templates have been considered The alternative templates correspond

82 Chapter 6 Systematics Evaluation

to the reconstructed open charmbeauty dimuons generated with the lower limit of theFONLL prediction range (offering the largest deviation from the corresponding referencetemplates see figure 412) and to the OS dimuons from the MC simulations of uncor-related muons already considered for the validation of the event mixing technique (seesection 512) Considering the alternative set of templates has an average impact of minus1for the ηrarr micro+microminusγ 2 for the ωrarr micro+microminus and 9 for the φrarr micro+microminus signals

616 Systematic Uncertainty ComputationAs already mentioned the systematic uncertainty on the signal extraction is computedseparately for the η rarr micro+microminusγ ω rarr micro+microminus and φ rarr micro+microminus processes as the standarddeviation of the distribution of value obtained from the systematic tests described above

σ2 = 1N

testssumi

(xi minus 〈x〉)2 (61)

where xi is the outcome of the i-th systematic test out of the N available tests andthe expectation value 〈x〉 is taken as the outcome of the reference fit This approach isjustified by the assumption that for each source of systematics the associated uncertaintycan be assumed to be Gaussian This evaluation is done for each pT-y interval consideredin this analysis

The global uncertainty on the signal extraction is reported in table 62 for the threesignals extracted with the fit procedure since its value depends on the pT and y intervalthe minimum and maximum values are quoted The average uncertainties correspondingto the considered systematic tests on the signal extraction are also reported in the table

Syst test ηrarr micro+microminusγ ωrarr micro+microminus φrarr micro+microminus

BR ηrarr micro+microminus lt 1 2 2 BR ωrarr micro+microminusπ0 3 3 2 Ratio σηprimeσφ lt 1 3 2 Ratio σρσω 1 2 2 Upper fit limit 5 6 8 Templates for the correlatedcontinuum 6 4 5

Standard deviation from (61) 1 - 22 2 - 12 1 - 16

Table 62 Summary of the systematic tests considered on the signal extraction procedure

62 Systematics from the MC inputThe first source of systematic uncertainty considered for the (Atimes ε) evaluation is thechoice of the input kinematic distributions assumed in MC simulations for the generatedη ρ ω ηprime and φ mesons see section 411 The reference choice being the correlated

63 Systematics on Trigger Efficiency 83

pT-y input from PHOJET the alternative MC input has been based on parametrized non-correlated pT and y distributions form PYTHIA6 The corresponding systematic uncer-tainty has been evaluated for each pT and y interval considered in this analysis by takingthe difference of the (Atimes ε) value estimated with the reference and the alternative MCinputs The corresponding average impact on the extraction of the signals of interest is5 55 and 1 respectively for the ηrarr micro+microminusγ ωrarr micro+microminus and φrarr micro+microminus signals

63 Systematics on Trigger Efficiency

The systematics on the trigger efficiency has been determined by comparing the proba-bility of reconstructing dimuons of a given kinematics with two different trigger responsefunctions one obtained from the data and the other from MC simulations The standardprocedure to estimate the systematic uncertainty from the trigger response function canbe summarized as follows

bull Fit the ratio low-pTA-pT obtained dividing the pT distribution of single muonsmatching the low-pT trigger condition by the pT distribution of single muons match-ing the A-pT condition (see paragraph e on section 223) This ratio is evaluatedboth in data and in realistic MC simulations and the corresponding fits define thetrigger response function

bull Select muons matching the A-pT trigger condition in the MC simulation of a specificdimuon signal and weigh each of them (according to their pT) by either the dataor the MC trigger response function

bull Extract the number of reconstructed dimuons under the two assumptions of thetrigger response function The difference is the systematics uncertainty of the triggerefficiency

631 Evaluation of the Trigger Response Function

The definition of the trigger response function given above cannot be used in the presentanalysis because in the considered data set the low-pT and the A-pT trigger matchingconditions coincide Therefore an alternative definition of the trigger response function isadopted here namely the ratio low-pTAll where the denominator is the pT distributionof All reconstructed muons imposing no trigger matching condition

Unfortunately this new definition of the trigger response function cannot be safelyapplied to the data because the All muon sample is contaminated by a non-negligiblehadronic component In this case one can still estimate the low-pTAll for the datastarting from the ratio of the corresponding MC ratio through a dataMC conversionfactor This conversion factor is defined as the ratio between the trigger response functionslow-pTA-pT of data and MC estimated in a dataset (B) as close as possible to the one(A) considered in the present analysis and characterized by different thresholds for the

84 Chapter 6 Systematics Evaluation

low-pT and A-pT trigger matching conditions

low-pT

All

∣∣∣∣∣data

A

(pT) = low-pT

All

∣∣∣∣∣MC

A

(pT)timeslow-pTA-pT

∣∣∣dataB

(stimes pT)low-pTA-pT

∣∣∣MC

B(stimes pT)

(62)

with the pT dependence of the trigger response functions in the reference dataset B beingldquostretchedrdquo by the s factor

s = pcutT (MC B)pcutT (MC A) (63)

where pTcut(MC x) is defined as the pT value for which the trigger response function

(low-pTAll or low-pTA-pT respectively for the datasets A and B) reaches half the dif-ference between the maximum and minimum This approach is correct as long as twoassumptions are valid

bull the trigger response per local board does not change with time

bull the relative difference dataMC between the low-pTA-pT trigger response func-tions from data and MC does not change when considering the low-pTAll triggerresponse functions

The low-pTA-pT trigger response functions defining the dataMC conversion factorin equation (62) can be replaced by a parametrization given by the function

F (pT pcutT σ) = 1 + p0 times

erfpT minus pcut

Tsradic

2σs

minus 1 (64)

based on the three free parameters p0 pcutT and σIn the present analysis the reference dataset B has been assumed to be the 2015 Pb-Pb

dataset (restricted to the peripheral collisions in the 60-100 centrality class) taken atradics = 502 TeV this choice is also used in other dimuon analyses based on the pp dataset

atradics = 5 TeV and the p-Pb dataset at radicsNN = 5 mdash 816 TeV

632 ResultsThe two versions of the trigger re-weighting described above produced two alternativeestimations of the (Atimes ε) for the three considered processes For each pT-y cell consideredin the analysis we retained the alternative version giving the largest deviation with respectto the reference value this deviation is shown in the form of a ratio in figure 62 Theabsolute deviation of this ratio is taken as the systematic uncertainty on the triggerefficiency the average values of this uncertainty are 2 06 and 1 respectively forthe ηrarr micro+microminusγ ωrarr micro+microminus and φrarr micro+microminus processes In the analysis this uncertaintyhas been evaluated for each specific pT-y cell considered for the extraction of the signalSystematic uncertainty values as large as 30 were tolerated in this analysis this resultedin the exclusion of the (minus350 lt y lt 325 04 lt pT lt 06 GeVc) interval for theηrarr micro+microminusγ signal affected by a systematic on the trigger efficiency larger than 70

64 Systematics on Tracking Efficiency 85

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

06

07

08

09

1

11

12

13

14 RefTrigg-reweight

γmicromicrorarrη ]εtimes[ A

(a) ηrarr micro+microminusγ

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

06

07

08

09

1

11

12

13

14 RefTrigg-reweightmicromicrorarrω ]εtimes[ A

(b) ωrarr micro+microminus

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

06

07

08

09

1

11

12

13

14 RefTrigg-reweight

micromicrorarrφ ]εtimes[ A

(c) φrarr micro+microminus

Figure 62 Ratio of Atimes ε for original simulation over the re-weighted simulation for estimating thesystematics associated to the trigger efficiency

64 Systematics on Tracking Efficiency

The systematics on tracking efficiency is one of the contributions to the uncertainty on the(Atimes ε) estimation To compute this uncertainty one has to evaluate the ratio betweenthe tracking efficiencies of data and MC

641 Preliminary Check

Before studying the tracking efficiencies in data and MC it must be verified that thestatus of the detector described in the realistic MC simulations is compatible with thestatus of the detector reflected by the data This is done by inspecting the cluster mapsof the tracking chambers in data and MC in this way one can verify whether the deadareas in the data are correctly reproduced in the MC and no additional dead area isintroduced An example of such comparison is shown in figure 63

Another point to be checked is the variation of the high voltage supplied to the track-ing chambers with respect to the value 16 kV corresponding to the nominal operatingconditions During Run 2 indeed some frequent high voltage drops to 14 kV were spot-ted resulting in a degraded efficiency of the chambers Since this intermediate behaviorbetween the full operation and the off status cannot be easily reproduced in MC specificdetector elements being significantly affected by high voltage drops are added to a ldquorejectlistrdquo and excluded from the reconstruction both in data and MC Alternatively when thispathological high voltage behavior only affects a limited fraction of the considered datasample full runs can be excluded it was the case in the present analysis where 4 runsof the LHC16n period were rejected to avoid major discrepancies between data and MC

After checking the agreement between data and MC concerning the detector statusand the behavior of the high voltage it is possible to launch the evaluation of the trackingefficiency both in data and MC

86 Chapter 6 Systematics Evaluation

Figure 63 Comparison between cluster maps of tracking chamber 4 in data (left) and MC (right)

642 Tracking Efficiency EvaluationThe tracking efficiency (εglobal) is computed as the product of the efficiency (εSti) of eachtracking station

εglobal = εSt1 middot εSt2 middot εSt3 middot εSt45 (65)

The fact the efficiencies of stations 4 and 5 are combined together in the efficiency εSt45 isdue to the logic operating mode implemented in the tracking algorithm [7894] requiringone cluster per station for stations 1 2 and 3 and three clusters from the combinedstations 4-5

Ch1 Ch2 Ch3 Ch4 Ch5 Ch6 Ch7 Ch8 Ch9 Ch10

NSt21-1

St1 St2 St3 St4 St5

NSt20-1

NSt21-0

NSt20-0

St45

Figure 64 Sketch showing the arrangement of the chambers into stations and the possible responsesof one station to the passage of a particle

64 Systematics on Tracking Efficiency 87

To evaluate the efficiency of a given station one has to start considering the efficiencyof the chamber composing the station (see section 223 for a more detailed description ofthe muon spectrometer structure) To evaluate the efficiency of each tracking chamberthe assumption is done that its efficiency does not depend on the efficiency of the otherchambers under this assumption the redundancy of the information given by the twochambers of a specific station can be used to determine the efficiency of each chamberseparately Figure 64 shows the possible responses of station 2 to the passage of aparticle Generalizing to the case of an arbitrary station k the reconstructed track canhave a cluster in both chambers (NStk

1-1 ) a cluster either in the first or the second of thetwo stations (NStk

1-0 or NStk0-1 ) or the track does not fulfill the tracking conditions so it is not

reconstructed (NStk0-0 ) Still focusing on station k composed of chamber i and j(= i+ 1)

one can express the number of reconstructed tracks (Ntot each of them crossing stationk due to the conditions imposed by the tracking algorithm) as

Ntot = NStk1-1 +NStk

0-1 +NStk1-0 (66)

Under the assumption that the efficiencies of chambers i and j are independent NStk1-1

NStk1-0 and NStk

0-1 can be expressed as a function of Ntot

NStk1-1 = Ntot middot εChi middot εChj (67)

NStk1-0 = Ntot middot εChi middot (1minus εChj) (68)

NStk0-1 = Ntot middot (1minus εChi) middot εChj (69)

By combining the above equations the efficiencies of chamber i and j are given by

εChi = NStk1-1

NStk1-1 +NStk

0-1εChj = NStk

1-1NStk

1-1 +NStk1-0

(610)

The individual chamber efficiencies can be combined to compute the efficiency of eachstation In the case of the first three stations the efficiency is defined as the probabilityfor a muon to be detected by at least one of the two chambers

εSt1(23) = 1minus(1minus εCh1(35)

) (1minus εCh2(46)

)= εCh1(35) εCh2(46) +

(1minus εCh1(35)

)εCh2(46) + εCh1(35)

(1minus εCh2(46)

) (611)

For the last two stations the efficiency has to be calculated as a whole due to the trackingalgorithm requirements This efficiency is the probability that a muon is detected by atleast three out of the four chambers in the stations the corresponding formula is thegeneralization of equation (611)

εSt45 =10prodi=7

εChi +10sumi=7

(1minus εChi)10prodj=7j 6=i

εChj

(612)

88 Chapter 6 Systematics Evaluation

643 MC parametrization

In order the tracking efficiency estimation in the MC to be reliable the considered para-metric muon generator must be tuned in order to reproduce the reconstructed kinematicsof the single muons measured in pp collisions at

radics = 13 TeV considered in the present

analysis The tuning is performed by means of a recursive procedure illustrated in fig-ure 65 which includes the following steps

1 Run MC simulations of single muons with given input pT and y distributions

2 Compute the (Atimes ε) as a function of pT and y

3 Use the (Atimes ε) to correct the reconstructed muon distributions from data

4 Compute the ratio as a function of both pT and y between the corrected datadistribution and the kinematic distributions considered for the MC input Shouldthis ratio be compatible with one convergence is reached and the procedure isstopped

5 Inject the corrected pT and y data distributions as the new input for MC simulation

until step 4 is equal to one

First Set of MC simulation

MC gen distribMC rec distrib

MC (Atimes ε)Rec

data distrib

Data corr distrib

Datacoor distrib =MC gen distrib

Data corr distrib rarr MC gen distrib

Done

1

2

3 34

No

Yes

51

Figure 65 Illustration of the data driven method used to tune the input distribution of single muon

65 Summary of Systematic Uncertainty 89

644 ResultsTracking efficiency estimations from the data and from the tuned MC simulation areshown in figure 66 as a function of pT y the azimuthal angle ϕ and the run number A2 systematic uncertainty is observed in average for single muon from the comparisonbetween data and MC For the dimuon signals the systematic uncertainty on the trackingefficiency is estimated to be twice the systematics on the single muons in this case thisresults in a 4 systematic uncertainty independent of pT and y

run number

2536

59

2541

28

2543

78

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

effic

ienc

y

0

02

04

06

08

1

Simulation Data

run number2536

59

2541

28

2543

78

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

EffD

ata

EffS

im

09

1

11

B TeyssierWork Thesis

Figure 66 Tracking efficiency measured in data and in the tuned MC simulation as a function ofrun number

65 Summary of Systematic UncertaintyIn table 63 are summarized the various sources of systematic uncertainties discussed inthis chapter For each of these sources and each signal of interest for this analysis wereport the value of the systematic uncertainty when the uncertainty values depend onthe pT or the y interval their maximum and minimum values are quoted

Syst source η ω φ

Signal extraction 1 - 22 2 - 12 1 - 157 MC input 5 55 1 Trigger efficiency 1 - 31 1 - 24 1 - 25 Branching ratio 13 2 1 Tracking efficiency 4 Luminosity 5

Table 63 Summary of the systematic uncertainty sources contributing to the measurement of theη ρω and φ meson cross-section

Chapter 7

Light Neutral Meson Production

Summary71 Estimation of the Number of Generated Mesons 91

711 The Two-Body Decay Case 91712 The Dalitz Decay Case 92

72 Cross-Section Production for Light Neutral Mesons 93

721 Double-Differential η Meson Production 93722 ρω Meson Production 94723 Double-Differential φ Meson Production 98

This chapter describes the steps followed to convert the reconstructed signal into cross-section for the η ρω and φ mesons The pT dependence of the production cross-sectionis extracted in six y intervals and compared to the predictions of the available modelsIn the case of the φ and ρω mesons the pT dependence of the rapidity-integratedcross-section is also derived allowing for the comparison with the results from existingmeasurements in pp collisions in the same rapidity range

71 Estimation of the Number of Generated MesonsThe very first step after signal extraction consists in correcting the number of recon-structed dimuons for the Atimesε evaluated with the MC simulations discussed in section 41In the case of the two-body decays ρω rarr micro+microminus and φ rarr micro+microminus the information onthe dimuons can be directly converted into the corresponding information on the parentmesons by correcting for the branching ratios of the involved decays In the case of theDalitz decay ηrarr micro+microminusγ an additional step is required to convert the dimuon kinematicsto the η meson one before correcting for the branching ratio

711 The Two-Body Decay CaseAs far as the two-body decays of the ρω and φ mesons are concerned the corrected num-ber of mesons (Nρω and Nφ respectively) corresponding to the reconstructed dimuonsN recmicromicro is given for each pT-y interval considered in this analysis by the following formula

Nρω φ(pT y) =N recmicromicro (pT y)

[Atimes ε]micromicro (pT y) middotBRmiddot ∆pT middot ∆y (71)

92 Chapter 7 Light Neutral Meson Production

where [Atimes ε]micromicro (pT y) is the product of the acceptance and the dimuon reconstructionefficiency evaluated in the specific pT-y cell BR is the branching ratio of the considereddecay channel (see table 43) and ∆pT middot ∆y are the widths of the pT-y cell For theestimation relative to the ρω mesons N rec

micromicro (pT y) [Atimes ε]micromicro (pT y) and the BR arereferred to the ωrarr micro+microminus decay

712 The Dalitz Decay Case

When dealing with the Dalitz decay of the η we start by correcting the number ofreconstructed dimuons for the Atimes ε and the widths of the considered pT-y cell

Ngenmicromicro (pT y) =

N recmicromicro (pT y)

[Atimes ε]micromicro (pT y) middot ∆pT middot ∆y (72)

Contrary to the two-body case the corrected kinematics distribution of the dimuon doesnot coincide with the one of the parent meson due to the Dalitz decay kinematics implyinga third body

)ηyηT

pId(0 50 100 150 200 250 300

)micromicroymicromicro T

pId

(

0

50

100

150

200

250

300

1

10

210

310

410

510

610

710

810

)micromicroy micromicroT

p ηy ηT

pT(

Figure 71 Correlation matrix T(pηT yη pmicromicroT ymicromicro) represented in cell coordinates

72 Cross-Section Production for Light Neutral Mesons 93

So to obtain the correct kinematic distributions of the parent η meson an additionaltransformation is needed

Nηrarrmicromicroγ(pT y) = Tminus1 middot Ngenmicromicro (pT y) (73)

where Tminus1 is the inverse of the matrix encoding the correlation between the kinematics ofthe parent η meson and the one of the dimuon both expressed in terms of pT and y TheT(pηT yηp

micromicroT y

micromicro) is shown in figure 71 each T(pηT yη pmicromicroT y

micromicro) element of the matrix isdefined as the probability of an η meson with a given (pηT yη) kinematics to produce adimuon with a given (pmicromicroT ymicromicro) kinematics so that one can write

Ngenmicromicro (pT y) = Tmiddot Nηrarrmicromicroγ(pT y) (74)

from which equation (73) is derived The row-column indexes of the elements of theTmatrix identify a specific pηT yη and pmicromicroT ymicromicro cell respectively In this specific analysisthe phase space limits considered for both the η and the dimuon are 20 lt y lt 45 and00 lt pT lt 150 GeVc in this way any possible edge effect affecting the numericalproblem will have a limited impact on the phase space covered by the available data

Once the correction expressed by equation (73) is performed the resulting kinematicdistribution is further scaled for the η rarr micro+microminusγ branching ratio in order to obtain thecorrect normalization for the Nη(pT y) distribution

72 Cross-Section Production for Light NeutralMesons

The Nηρωφ(pT y) distributions obtained after correcting for the Atimesε and the branchingratio (and for the meson-dimuon kinematic correlation in the case of the η) must be furthernormalized to the integrated luminosity Lint corresponding to the analyzed data sample(the evaluation of the integrated luminosity is discussed in section 32) This normalizationallows one to obtain the cross-section for the three mesons

d2σ(pT y)dpTdy = Nηρωφ(pT y)times 1

Lint (75)

721 Double-Differential η Meson Production

In figure 72 the pT distributions of the dimuon coming from the η rarr micro+microminusγ decay areshown for the six y interval considered in this analysis These distributions representthe Ngen

micromicro (pT y) input from which the kinematic distribution of the parent meson can beextracted via equation (73) The implementation in the current analysis of the kinematiccorrection based on equation (73) is however still under way for this reason no resulton the η meson cross-section is shown in the rest of the chapter

94 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

ydT

pd η

dN

510

710

910

1110

13100250 lt y lt 275 x 101275 lt y lt 300 x 102300 lt y lt 325 x 103325 lt y lt 350 x 104350 lt y lt 375 x 105375 lt y lt 400 x 10

B TeyssierWork Thesis

Figure 72 Comparison of the pT distribution of η dimuon generated as a function of y

722 ρω Meson ProductionFor the ρω mesons the double-differential pT-y production cross-section has been eval-uated in the available phase space the results are shown in figure 73 as a function ofpT in six y intervals For each y interval the measured cross-section has been comparedto the predictions of PYTHIA8-Monash2013 [95] and PHOJET The comparison is shown inthe panels of figure 74 the two models systematically overestimate by a factor sim 2 thedata in the full accessible pT range for each of the considered y intervals

In figure 75 the y dependence of the production cross-section is shown integratedover the pT range 20 lt pT lt 65 GeVc common to the considered y intervals Thecomparison with the predictions from PYTHIA8-Monash2013 and PHOJET confirms thatthe models overestimate the data by a factor sim 2 Besides the global overestimation thePHOJET prediction seems to provide a better description than PYTHIA8-Monash2013 of they dependence of the data

The ρω production cross-section was also measured in ALICE in pp collisions atradics =

7 TeV integrated over 25 lt y lt 40 as a function of pT in the 10 lt pT lt 50 GeVcrange In order to compare our data to the ones at

radics = 7 TeV the production cross-

section measured in this analysis has been integrated over the full accessible 25 lt y lt 40range As it can be seen from figure 73 the integration over 25 lt y lt 40 was possiblelimited to the 20 lt pT lt 65 GeVc range The comparison between the two energiesshows that the 13 TeV cross-section is larger than the 7 TeV one by a factor sim 2 seefigure 76

72 Cross-Section Production for Light Neutral Mesons 95

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

210

310

410

510

610

0250 lt y lt 275 x 10

1275 lt y lt 300 x 10

2300 lt y lt 325 x 10

3325 lt y lt 350 x 10

4350 lt y lt 375 x 10

5375 lt y lt 400 x 10

B TeyssierWork Thesis

Figure 73 Comparison of the pT distribution of ω meson as a function of y

96 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

375 lt y lt 400

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

3minus10

2minus10

1minus10

1

10350 lt y lt 375

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

325 lt y lt 350

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

300 lt y lt 325

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

275 lt y lt 300

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

250 lt y lt 275

Pythia8

PHOJETB Teyssier

Work Thesis

Figure 74 pT distributions of ω meson for various y intervals

72 Cross-Section Production for Light Neutral Mesons 97

y4minus 2minus 0 2 4

[mb]

yωσd

0

05

1

15

2

25

3

(reflected)ω

(measured)ω

Pythia8 - monash2013

Phojet

c lt 65 GeVT

p20 lt

B TeyssierWork Thesis

Figure 75 y distribution of ω meson integrated in 20 lt pT lt 65 GeVc

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσ2 d

3minus10

2minus10

1minus10

1

=7TeVspp at

=13TeVspp at

B TeyssierWork Thesis

Figure 76 pT distribution of ω meson integrated in y and comparison with measurements at7 TeV [43]

98 Chapter 7 Light Neutral Meson Production

723 Double-Differential φ Meson ProductionAs for the ρω mesons the double-differential pT-y production cross-section has beenevaluated for the φ meson too in the available phase space the results are shown infigure 77 as a function of pT in the y intervals considered in the analysis extended at mid-rapidity with the φ rarr K+Kminus measurements [96] The comparison of the data with thepredictions of the PYTHIA8-Monash2013 and PHOJET models is shown for each y intervalconsidered in the analysis in the panels of figure 78 contrary to what observed for theω meson the PYTHIA8-Monash2013 prediction provides a good description of the dataThe PHOJET prediction on the contrary still slightly fails in estimating the normalizationand the shape of the pT dependence of the production cross-section

The y dependence of the production cross-section is shown in figure 79 integratedover the pT range 20 lt pT lt 65 GeVc common to the considered y intervals As one cansee the data points sit between the predictions from PYTHIA8-Monash2013 and PHOJETwhich both slightly fail in describing the shape of the y dependence The results for theφ meson production in the dikaon channel provide an additional point at mid-rapiditywhich could be compared to the forward measurements presented here

Results for the φ meson production cross-section are also available from ALICE mea-surements in pp collisions at

radics = 276 502 7 and 8 TeV integrated over 25 lt y lt 40

as a function of pT in various pT ranges In order to compare our data to the ones atlower energies the φ meson production cross-section measured in this analysis has beenintegrated over the full accessible 25 lt y lt 40 range As it can be seen from figure 77this integration was possible limited to the 20 lt pT lt 65 GeVc range As expected thecross-section at 13 TeV is found to be larger than the measurements at lower energies

The energy dependence of the φ meson production cross-section has been studiedintegrating the present measurement over the y and pT ranges 25 lt y lt 40 and15 lt pT lt 50 GeVc common to the data at the various available energies Theresults are shown in figure 711 compared with the PYTHIA8-Monash2013 and PHOJETprediction the trend as a function of

radics is found to be approximately linear in the con-

sidered energy range with the PHOJET model in good agreement with the data and thePYTHIA8-Monash2013 prediction systematically underestimating the results The analysisstrategy at 13 TeV is being slightly revised in order to reduce the systematic uncertaintyassociated to the integrated cross-section by optimizing the integration procedure namelyintegrating over the rapidity before signal extraction

72 Cross-Section Production for Light Neutral Mesons 99

]c [GeVT

p0 2 4 6 8 10 12

)]c [m

b(G

eV

ydT

pd φσd

4minus10

3minus10

2minus10

1minus10

1

10

210

310

410

510

-1|lt05 x 10y |-

K+ Krarrφ0250 lt y lt 275 x 10

1275 lt y lt 300 x 10

2300 lt y lt 325 x 103325 lt y lt 350 x 10

4350 lt y lt 375 x 10

5375 lt y lt 400 x 10

B TeyssierWork Thesis

Figure 77 Comparison of the pT distribution of φ meson as a function of y extended at mid-rapidityby the φrarr K+Kminus measurements [96]

100 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1375 lt y lt 400

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

350 lt y lt 375

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1325 lt y lt 350

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

300 lt y lt 325

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

275 lt y lt 300

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

250 lt y lt 275

Pythia8

PHOJETB Teyssier

Work Thesis

Figure 78 pT distribution of φ meson for various y intervals

72 Cross-Section Production for Light Neutral Mesons 101

y4minus 2minus 0 2 4

[mb]

y φσd

0

01

02

03

04

05

(refkected)φ (dikaon measurement)φ (measured)φ

Pythia8 - monash2013

Phojet

c lt 65 GeVT

p20 lt

B TeyssierWork Thesis

Figure 79 y distribution of φ meson integrated in 20 lt pT lt 65 GeVc extended at mid-rapidityby the φrarr K+Kminus measurements [96]

102 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσ2 d

3minus10

2minus10

1minus10

1 =276TeVspp at

=5TeVspp at

=7TeVspp at

=8TeVspp at

=13TeVspp at

lt 40y25 lt

B TeyssierWork Thesis

Figure 710 φ meson pT distribution integrated over 25 lt y lt 40 in pp collisions atradics = 13 TeV

(this analysis) compared to previous measurements at lower energies

72 Cross-Section Production for Light Neutral Mesons 103

B TeyssierWork Thesis

Figure 711 Energy dependence of the φ meson production cross-section in 25 lt y lt 40 and15 lt pT lt 50 GeVc

Conclusions and Perspectives

This work focused on the study of the production cross-section of the η ρω and φmesons This study has been achieved by performing a double-differential pT-y analysisin the phase space available for each meson Results have been compared to the availabletheoretical predictions from the PYTHIA8 and PHOJET models this comparison resultedin a better datamodel agreement for the φ meson than for the ρω meson Moreoverexisting results at several lower collision energies in the same y interval allowed toinvestigate the energy evolution of the production cross-section for the φ meson andlimited to the comparison with the

radics = 7 TeV results for the ρω mesons For the φ

meson the energy evolution of the production cross-section integrated over 25 lt y lt 40and 15 lt pT lt 50 GeVc was found to be approximately linear with the PHOJET modelin good agreement with the data and the PYTHIA8-Monash2013 prediction systematicallyunderestimating the results In a next future the results for the φ meson from thepresent analysis could also be compared to the mid-rapidity measurement performed inALICE in the dikaon channel

The present analysis did not exploit the full potential of the large data sample availablein pp collisions at

radics = 13 TeV which could possibly profit from the combination of the

2016 and 2017 data taking Among the measurements which could still be performedbased on the analysis of the low-mass dimuon region one can cite

bull the study of the multiplicity dependence of the light-neutral meson production

bull the search for strangeness enhancement collective phenomena and azimuthalanisotropies in light-neutral meson production in high-multiplicity pp events

bull the study of the light-neutral meson polarization

Finally beyond the standard dimuon analyses the large pp data sample atradics = 13 TeV

could also be exploited for the search of the first evidence of the η rarr 2micro+2microminus decayfor which only an upper limit is currently available from literature [4] The proximity ofthe η meson mass to the 4mmicro threshold makes the observation of this decay particularlychallenging and sensitive to the description to the combinatorial background

Appendix A

List of Runs

000253659 000253680 000253682 000253748 000253751 000253755 000253756 000253757000253813 000253819 000253825 000253826 000253832 000253834 000253951 000253956000253957 000253958 000253961 000253978

Table A1 Run list for period LHC16f

000254128 000254147 000254148 000254149 000254174 000254175 000254178 000254193000254199 000254204 000254205 000254293 000254302 000254304 000254331 000254332

Table A2 Run list for period LHC16g

000254378 000254381 000254394 000254395 000254396 000254419 000254422 000254476000254479 000254604 000254606 000254608 000254621 000254629 000254630 000254632000254640 000254644 000254646 000254648 000254649 000254651 000254652 000254653000254654 000254983 000254984 000255008 000255009 000255010 000255042 000255068000255071 000255073 000255074 000255075 000255076 000255079 000255082 000255085000255086 000255091 000255111 000255154 000255159 000255162 000255167 000255171000255173 000255176 000255177 000255180 000255182 000255240 000255242 000255247000255248 000255249 000255251 000255252 000255253 000255255 000255256 000255275000255276 000255280 000255283 000255350 000255351 000255352 000255398 000255402000255415 000255440 000255442 000255447 000255463 000255465 000255466 000255467000255469

Table A3 Run list for period LHC16h

000255515 000255533 000255534 000255535 000255537 000255538 000255539 000255540000255542 000255543 000255577 000255583 000255591 000255592 000255614 000255615000255616 000255617 000255618

Table A4 Run list for period LHC16i

108 Appendix A List of Runs

000256146 000256147 000256148 000256149 000256156 000256157 000256158 000256161000256169 000256204 000256207 000256210 000256212 000256213 000256215 000256219000256222 000256223 000256227 000256228 000256231 000256281 000256282 000256283000256284 000256287 000256289 000256290 000256292 000256295 000256297 000256298000256302 000256307 000256311 000256356 000256357 000256361 000256362 000256363000256364 000256365 000256366 000256368 000256372 000256373 000256415 000256417000256418 000256420

Table A5 Run list for period LHC16j

000256504 000256506 000256510 000256512 000256552 000256554 000256556 000256557000256560 000256561 000256564 000256565 000256567 000256589 000256591 000256592000256619 000256620 000256658 000256676 000256677 000256681 000256684 000256691000256694 000256695 000256697 000256941 000256942 000256944 000257011 000257012000257021 000257026 000257028 000257071 000257077 000257080 000257082 000257083000257084 000257086 000257092 000257095 000257224 000257260 000257318 000257320000257322 000257330 000257358 000257364 000257433 000257457 000257468 000257474000257487 000257488 000257490 000257491 000257492 000257530 000257531 000257540000257541 000257560 000257561 000257562 000257563 000257564 000257565 000257566000257587 000257588 000257590 000257592 000257594 000257595 000257601 000257604000257605 000257606 000257630 000257632 000257635 000257636 000257642 000257644000257682 000257684 000257685 000257687 000257688 000257694 000257697 000257724000257725 000257727 000257733 000257734 000257735 000257737 000257892 000257893000257901 000257912 000257932 000257936 000257937 000257939 000257957 000257958000257960 000257963 000257979 000257986 000257989 000258008 000258012 000258014000258017 000258019 000258039 000258041 000258042 000258045 000258048 000258049000258059 000258060 000258062 000258063 000258107 000258108 000258109 000258113000258114 000258117 000258178 000258197 000258202 000258203 000258204 000258256000258257 000258258 000258270 000258271 000258273 000258274 000258278 000258280000258299 000258301 000258302 000258303 000258306 000258307 000258332 000258336000258359 000258387 000258388 000258391 000258393 000258399 000258426 000258452000258454 000258456 000258477 000258498 000258499 000258537

Table A6 Run list for period LHC16k

000258919 000258920 000258921 000258923 000258931 000258962 000258964 000259086000259099 000259117 000259118 000259162 000259164 000259204 000259261 000259263000259264 000259269 000259270 000259271 000259272 000259273 000259274 000259302000259303 000259305 000259307 000259334 000259339 000259340 000259341 000259342000259378 000259379 000259381 000259382 000259394 000259395 000259396 000259469000259471 000259477 000259649 000259650 000259668 000259697 000259700 000259703000259704 000259705 000259711 000259713 000259750 000259751 000259756 000259788000259789 000259822 000259841 000259842 000259860 000259866 000259867 000259868000259888 000259954 000259961 000259979 000260010 000260011 000260014

Table A7 Run list for period LHC16l

109

000260218 000260240 000260310 000260312 000260313 000260338 000260340 000260351000260354 000260357 000260379 000260411 000260432 000260435 000260437 000260440000260441 000260447 000260471 000260472 000260475 000260476 000260481 000260482000260487 000260490 000260495 000260496 000260497 000260537 000260539 000260540000260541 000260542 000260564 000260586 000260611 000260613 000260614 000260615000260616 000260647

Table A8 Run list for period LHC16m

000260649 000260650 000260657 000260667 000260671 000260672 000260689 000260691000260693 000260695 000260700 000260704 000260710 000260713 000260722 000260723000260727 000260728 000260740 000260741 000260749 000260750 000260751 000260752000260763 000260770 000260777 000260782 000260784 000260786 000260788 000260804000260808 000260809 000260810 000260815 000260913 000260914 000260920 000260934000260935 000260936 000260938 000260960 000260963 000260992 000260993 000261020000261022 000261025 000261026 000261027 000261052 000261055 000261065 000261076000261083 000261088 000261093 000261094 000261095 000261099 000261100

Table A9 Run list for period LHC16n

000262399 000262418 000262419 000262422 000262423 000262424 000262428 000262430000262451 000262487 000262492 000262528 000262532 000262533 000262537 000262563000262567 000262568 000262569 000262570 000262571 000262572 000262574 000262578000262583 000262593 000262594 000262628 000262632 000262635 000262705 000262706000262713 000262717 000262719 000262723 000262725 000262727 000262760 000262768000262776 000262777 000262778 000262841 000262842 000262844 000262847 000262849000262853 000262855 000262858 000263332 000263487 000263490 000263496 000263497000263647 000263652 000263653 000263654 000263657 000263662 000263663 000263682000263689 000263690 000263691 000263737 000263738 000263739 000263741 000263743000263744 000263784 000263785 000263786 000263787 000263790 000263792 000263793000263803 000263810 000263813 000263823 000263824 000263829 000263830 000263861000263863 000263866 000263905 000263916 000263917 000263920 000263923 000263977000263978 000263979 000263981 000263984 000263985 000264033 000264035

Table A10 Run list for period LHC16o

000264076 000264078 000264082 000264085 000264086 000264109 000264110 000264129000264137 000264138 000264139 000264164 000264168 000264188 000264190 000264194000264197 000264198 000264232 000264233 000264235 000264238 000264259 000264260000264261 000264262 000264264 000264265 000264266 000264267 000264273 000264277000264279 000264281 000264305 000264306 000264312 000264336 000264341 000264345000264346 000264347

Table A11 Run list for period LHC16p

Appendix B

Raw-Background Comparison mdashfigures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150

lt 275y250 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 300y275 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 325y300 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

25310times

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B1 Evolution of signal and combinatorial background shapes for 000 lt pT lt 020 GeVc

112 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

lt 275y250 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 300y275 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 325y300 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 375y350 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 400y375 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B2 Evolution of signal and combinatorial background shapes for 020 lt pT lt 040 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 275y250 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5

310times

lt 300y275 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20310times

lt 325y300 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 400y375 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B3 Evolution of signal and combinatorial background shapes for 040 lt pT lt 060 GeVc

113

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 275y250 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 300y275 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 325y300 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

80310times

lt 375y350 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 400y375 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B4 Evolution of signal and combinatorial background shapes for 060 lt pT lt 080 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 275y250 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8310times

lt 300y275 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 325y300 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 350y325 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

80310times

lt 375y350 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

50

310times

lt 400y375 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B5 Evolution of signal and combinatorial background shapes for 080 lt pT lt 100 GeVc

114 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600 lt 275y250 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 300y275 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 325y300 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 350y325 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60310times

lt 375y350 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 400y375 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B6 Evolution of signal and combinatorial background shapes for 100 lt pT lt 120 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 275y250 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 300y275 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

50310times

lt 325y300 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

310times

lt 350y325 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

310times

lt 375y350 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

50310times

lt 400y375 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B7 Evolution of signal and combinatorial background shapes for 120 lt pT lt 160 GeVc

115

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4310times

lt 275y250 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 300y275 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 325y300 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 375y350 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 400y375 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B8 Evolution of signal and combinatorial background shapes for 160 lt pT lt 200 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5310times

lt 275y250 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 300y275 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20310times

lt 350y325 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 375y350 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

310times

lt 400y375 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B9 Evolution of signal and combinatorial background shapes for 200 lt pT lt 240 GeVc

116 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 275y250 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

310times

lt 300y275 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12310times

lt 325y300 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

310times

lt 375y350 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5

310times

lt 400y375 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B10 Evolution of signal and combinatorial background shapes for 240 lt pT lt 280 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 275y250 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 300y275 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 325y300 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5

310times

lt 350y325 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 375y350 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3310times

lt 400y375 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B11 Evolution of signal and combinatorial background shapes for 280 lt pT lt 320 GeVc

117

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25310times

lt 275y250 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 300y275 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 325y300 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 350y325 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 375y350 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 400y375 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B12 Evolution of signal and combinatorial background shapes for 320 lt pT lt 360 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 275y250 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 300y275 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3310times

lt 325y300 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 350y325 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 375y350 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 400y375 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B13 Evolution of signal and combinatorial background shapes for 360 lt pT lt 400 GeVc

118 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 300y275 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 325y300 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 350y325 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 375y350 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800

lt 400y375 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B14 Evolution of signal and combinatorial background shapes for 400 lt pT lt 450 GeVc

119

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800 lt 275y250 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310times

lt 300y275 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 325y300 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310times

lt 350y325 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 375y350 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 400y375 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B15 Evolution of signal and combinatorial background shapes for 450 lt pT lt 500 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 275y250 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 300y275 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310times

lt 325y300 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 350y325 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 375y350 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300 lt 400y375 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B16 Evolution of signal and combinatorial background shapes for 500 lt pT lt 550 GeVc

120 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400 lt 275y250 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 300y275 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 325y300 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 350y325 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800

lt 375y350 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150

200

250

lt 400y375 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B17 Evolution of signal and combinatorial background shapes for 550 lt pT lt 600 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

lt 275y250 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 300y275 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12310times

lt 325y300 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1310times

lt 350y325 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 375y350 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150 lt 400y375 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B18 Evolution of signal and combinatorial background shapes for 600 lt pT lt 650 GeVc

121

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

lt 275y250 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800

lt 300y275 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800 lt 325y300 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600 lt 350y325 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 375y350 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

80

100

120

140

lt 400y375 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B19 Evolution of signal and combinatorial background shapes for 650 lt pT lt 700 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400 lt 275y250 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 300y275 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 325y300 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 375y350 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150 lt 400y375 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B20 Evolution of signal and combinatorial background shapes for 700 lt pT lt 800 GeVc

122 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 300y275 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 325y300 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800 lt 350y325 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 375y350 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150

200

lt 400y375 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B21 Evolution of signal and combinatorial background shapes for 800 lt pT lt 1000 GeVc

Appendix C

Hadronic-Cocktail fits mdash figures

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C1 Hadronic cocktail fits for 000 lt pT lt 020 GeVc

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 350y325 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 040 GeVT

p020 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 375y350 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 040 GeVT

p020 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 400y375 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 040 GeVT

p020 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C2 Hadronic cocktail fits for 020 lt pT lt 040 GeVc

124 Appendix C Hadronic-Cocktail fits mdash figures

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 350y325 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 400y375 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C3 Hadronic cocktail fits for 040 lt pT lt 060 GeVc

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

12

14

310times

lt 350y325 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 080 GeVT

p060 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 375y350 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 080 GeVT

p060 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

25

310times

lt 400y375 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 080 GeVT

p060 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C4 Hadronic cocktail fits for 060 lt pT lt 080 GeVc

125

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 325y300 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

25

310times

lt 350y325 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

50

310times

lt 375y350 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 400y375 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 375 lt y lt 400

Figure C5 Hadronic cocktail fits for 080 lt pT lt 100 GeVc

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

12

14

310times

lt 325y300 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 350y325 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 375y350 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 400y375 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 375 lt y lt 400

Figure C6 Hadronic cocktail fits for 100 lt pT lt 120 GeVc

126 Appendix C Hadronic-Cocktail fits mdash figures

Not available fit in250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

12

310times

lt 300y275 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 325y300 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

50

310times

lt 350y325 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

50

310times

lt 375y350 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 400y375 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 375 lt y lt 400

Figure C7 Hadronic cocktail fits for 120 lt pT lt 160 GeVc

Not available fit in250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 300y275 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 325y300 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 350y325 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30310times

lt 375y350 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

310times

lt 400y375 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 375 lt y lt 400

Figure C8 Hadronic cocktail fits for 160 lt pT lt 200 GeVc

127

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 275y250 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 300y275 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

310times

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 350y325 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 375y350 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 400y375 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C9 Hadronic cocktail fits for 200 lt pT lt 240 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 275y250 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 300y275 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

5

310times

lt 400y375 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C10 Hadronic cocktail fits for 240 lt pT lt 280 GeVc

128 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

310times

lt 275y250 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 300y275 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 325y300 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

5

310times

lt 350y325 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 375y350 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

310times

lt 400y375 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C11 Hadronic cocktail fits for 280 lt pT lt 320 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 275y250 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 300y275 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 325y300 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

310times

lt 350y325 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 375y350 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 400y375 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C12 Hadronic cocktail fits for 320 lt pT lt 360 GeVc

129

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 275y250 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 300y275 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 325y300 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp lt 325y300 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 350y325 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 375y350 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

310times

lt 400y375 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C13 Hadronic cocktail fits for 360 lt pT lt 400 GeVc

130 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 300y275 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp lt 300y275 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times lt 325y300 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times lt 350y325 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

12

310times

lt 375y350 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

800

lt 400y375 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C14 Hadronic cocktail fits for 400 lt pT lt 450 GeVc

131

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

800

lt 275y250 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

12

14310times lt 300y275 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

310times

lt 325y300 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1310times

lt 350y325 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 375y350 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

500

lt 400y375 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C15 Hadronic cocktail fits for 450 lt pT lt 500 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 275y250 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

800

lt 300y275 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 325y300 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 350y325 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 375y350 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 400y375 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C16 Hadronic cocktail fits for 500 lt pT lt 550 GeVc

132 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 275y250 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 300y275 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

500

lt 325y300 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 350y325 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 375y350 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 400y375 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C17 Hadronic cocktail fits for 550 lt pT lt 600 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300 lt 275y250 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 300y275 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 325y300 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 350y325 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 375y350 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 400y375 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C18 Hadronic cocktail fits for 600 lt pT lt 650 GeVc

133

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200 lt 275y250 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 300y275 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 325y300 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 350y325 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 375y350 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

20

40

60

80

100

lt 400y375 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C19 Hadronic cocktail fits for 650 lt pT lt 700 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 275y250 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 300y275 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 325y300 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 375y350 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 400y375 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C20 Hadronic cocktail fits for 700 lt pT lt 800 GeVc

134 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 300y275 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 325y300 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 350y325 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 375y350 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375Not available fit in

375 lt y lt 400

Figure C21 Hadronic cocktail fits for 800 lt pT lt 1000 GeVc

Bibliography

[1] Michael E Peskin and Daniel V Schroeder An Introduction to Quantum FieldTheory Addison-Wesley 3 edition 1951 (Cited pages 1 et 7)

[2] C A Baker D D Doyle P Geltenbort and others Improved Experimental Limiton the Electric Dipole Moment of the Neutron Phys Rev Lett 97(13)131801September 2006 [link] (Cited page 4)

[3] SM Barr A review of CP violation in atoms International Journal of ModernPhysics A 08(02)209ndash236 January 1993 [link] (Cited page 4)

[4] C Patrignani K Agashe G Aielli and others Review of Particle PhysicsChinPhys C40100001 October 2016 [link] (Cited pages 4 5 7 54 56 58et 105)

[5] E Eichten K Gottfried T Kinoshita and others Charmonium The model PhysRev D 17(11)3090ndash3117 June 1978 [link] (Cited page 6)

[6] Gerardrsquot Hooft Symmetry Breaking Through Bell-Jackiw Anomalies PhysRevLett378ndash11 1976 (Cited page 10)

[7] S P Klevansky The Nambu-Jona-Lasinio model of quantum chromodynamics RevMod Phys 64649ndash708 1992 (Cited pages 10 et 12)

[8] P Costa C A de Sousa M C Ruivo and others The QCD critical end pointin the SU(3) NambundashJona-Lasinio model Physics Letters B 647(5)431ndash435 April2007 [link] (Cited page 10)

[9] J Stachel and G R Young Relativistic Heavy ION Physics at CERN and BNLAnnu Rev Nucl Part Sci 42(1)537ndash597 December 1992 [link] (Cited page 13)

[10] H R Schmidt and J Schukraft The physics of ultra-relativistic heavy-ion collisionsJ Phys G Nucl Part Phys 19(11)1705 1993 [link] (Cited page 13)

[11] RHIC Physics of the Relativistic Heavy Ion Collider 2017 [httpswwwbnlgovrhicphysicsasp] (Cited page 13)

[12] CERN Heavy ions and quark-gluon plasma [httpshomecernaboutphysicsheavy-ions-and-quark-gluon-plasma] (Cited page 13)

[13] ALICE Collaboration φ-meson production at forward rapidity in p-Pb collisionsat radicsNN = 502 TeV and in pp collisions at

radics = 276 TeV Physics Letters B

768203ndash217 May 2017 [link] (Cited pages 14 15 et 26)

[14] Michael L Miller Klaus Reygers Stephen J Sanders and others Glauber Model-ing in High-Energy Nuclear Collisions Annu Rev Nucl Part Sci 57(1)205ndash243October 2007 [link] (Cited page 14)

Eacutetude de la production de meacutesons neutres leacutegers dans la voie de deacutesinteacutegrationdimuonique en collisions proton-proton agrave

radics = 13 TeV agrave rapiditeacute vers lrsquoavant

dans ALICE au LHC du CERN

Reacutesumeacute La matiegravere qui nous entoure est formeacutee de hadrons eux-mecircmes constitueacutesde quarks et de gluons Ces derniers sont des composants eacuteleacutementaires qui nrsquoexistentpas sous forme libre Cependant nous savons agrave lrsquoheure actuelle que la matiegravere confineacuteedans des hadrons peut dans des conditions de haute tempeacuterature etou de haute densiteacutebaryonique se retrouver sous une forme deacuteconfineacutee de plasma de quarks et de gluons

Pour reacutealiser expeacuterimentalement les conditions permettant de former ce plasma dequarks et de gluons nous avons besoin drsquoune machine capable de faire entrer en collisionsdes noyaux agrave des eacutenergies tregraves eacuteleveacutees cela est notamment possible au CERN ougrave se situele plus grand acceacuteleacuterateur de particules du monde le Large Hadron Collider qui a permisde faire entrer en collisions des noyaux de Plomb agrave une eacutenergie par paire de nucleacuteonsde 276 et 502 TeV et des protons agrave des eacutenergies allant de 09 agrave 13 TeV Les collisionsentre noyaux de Plomb permettent en particulier drsquoatteindre les conditions de densiteacutedrsquoeacutenergie neacutecessaires agrave la formation de la phase de plasma de quarks et de gluons

Ce travail de thegravese contribue agrave ce programme de physique par lrsquoeacutetude de la productionde meacutesons neutres leacutegers en collisions proton-proton agrave 13 TeV reacutefeacuterence neacutecessaire pourcomprendre les observations en collisions Plomb-Plomb Lrsquoeacutetude des meacutesons neutres leacutegersa eacuteteacute meneacutee dans le canal dimuonique par lrsquoanalyse du spectre de masse invariante desdimuons de masse infeacuterieure agrave 15 GeVc2 permettant notamment de mesurer les sectionsefficaces des meacutesons η ρω et φ

Mots cleacutes CERN LHC ALICE QGP Chiraliteacute Muon Meacuteson Eacutetrangeteacute PhysiqueHadronique Physique des hautes eacutenergies

Remerciements

Je tiens tout drsquoabord agrave remercier lrsquoIPNL sous la direction de Guy Chanfray ainsi quele groupe ALICE de Lyon sous la direction de Brigitte Cheynis pour mrsquoavoir accueillipendant ces trois anneacutees Je tiens aussi agrave remercier le CNRS pour mrsquoavoir permis defaire cette thegravese gracircce agrave leur financement ainsi que le LAVEX LIO (Lyon Institute ofOrigins) de lrsquouniversiteacute de Lyon pour le serveur de calcul du groupe theacuteorie que jrsquoai eulrsquoopportuniteacute drsquoutiliser

Je voudrais remercier Barbara Erazmus qui a bien voulu ecirctre la preacutesidente de monjury de thegravese Roberta Arnaldi et Philippe Crochet pour avoir eacuteteacute mes rapporteurs quigracircce agrave leurs commentaires ont permis drsquoameacuteliorer la qualiteacute de ce manuscrit Merciaussi agrave Alberto Baldisseri et Hubert Hansen qui ont bien voulu ecirctre examinateurs decette thegravese ce qui a contribueacutee agrave lrsquoameacutelioration du document Je voudrais aussi vousremercier drsquoavoir fait le trajet sur Lyon pour avoir assisteacute agrave ma soutenance

Le groupe ALICE de Lyon mrsquoa permis de reacutealiser cette thegravese dans une bonne ambianceJe remercie Brigitte Cheynis ma directrice de thegravese avec qui jrsquoai pu avoir de nombreusesdiscussions que ce sois sur le VZERO pour ma tacircche de service au sein de la collaborationALICE sur des aspects scientifiques de mon analyse ou tous simplement sur lrsquoactualiteacuteainsi que pour les nombreuses corrections orthographiques que ce sois en anglais ou enfranccedilais qursquoelle a apporteacutees agrave mon travail Je tiens aussi agrave remercier Antonio mon co-encadrant de thegravese qui mrsquoa appris la ponctualiteacute italienne avec qui jrsquoai beaucoup apprissur lrsquoanalyse de donneacutees de ma thegravese et avec qui jrsquoai eu de nombreux eacutechangesdiscussionsque se sois scientifiques ou non Je voudrais aussi remercier Cvetan pour toutes lesdiscussions que jrsquoai pu avoir que ce sois sur le VZERO en lien avec ma tacircche de service ousur la physique hadronique et lrsquoexpeacuterience ALICE Ces discussions mrsquoont permis drsquoeacutelargirma vision du domaine Merci aussi agrave Laurent Ducroux pour les eacutechanges en lien aveclrsquoenseignement ainsi que les conseils apregraves mes diffeacuterentes preacutesentations au laboratoireMerci aussi agrave Raphaeumll pour les divers eacutechanges ainsi que sur lrsquoaide apporteacute durant lapreacuteparation de lrsquooral et agrave Massimiliano pour ces quelques mois au laboratoire en tantque nouveau post-doc du groupe ougrave tes conseils et points releveacutes durant ma preacuteparationdrsquooral ont eacuteteacute utile En plus des permanents et post-doc le groupe agrave accueilli des stagiairesdurant ma preacutesence dans le groupe et jrsquoaimerai les remercier pour la bonne humeur etambiance qursquoils sont apporteacutes tous particuliegraverement ceux qui ont cocirctoyeacute mon bureau quece sois pour deux ou six mois merci agrave Thibault Pierre Demongodin Samuel et AlexandreThyvollet ainsi que Pierre-Etienne et Satya pour leur bonne humeur et leur motivationpour participer au tournoi de volley de lrsquoAPPN

Je souhaiterais aussi remercier Hubert et Alexandre Biguet pour leur eacutechanges sur laQCD et la physique hadronique theacuteorique que jrsquoai pu avoir

Je souhaiterai aussi remercier les membres de lrsquoobservatoire des sciences de lrsquouniversqui mrsquoont permis de reacutealiser une tacircche drsquoenseignement pendant deux ans de ma thegravese

vi

Merci agrave Jean-Philippe Perrillat Jean-Franccedilois Gonzalez et Laurent Ducroux pour mrsquoavoirpris dans leur eacutequipe drsquoenseignement cela a eacuteteacute une expeacuterience tregraves enrichissante

I would like to thank all the ALICE collaboration that allowed me to do this thesisand especially I thank all the collaborators who contributed at the lmmumu PAG inparticular Alessandro Di Falco and Ester Casula from the INFN of Cagliari for theirhelp and advice given during the thesis Satoshi Yano from the Hiroshima university forhis contribution of the pp at 13 TeV In addition to the PAG collaborator I would liketo thanks all the DQ people and in particular Diego Laurent Aphecetch and PhilippePillot for their help in the evaluation of the muon arms systematics Martino for all theenriching exchanges on the operation of the ALICE trigger system and the luminosityEvgeny for his response concerning the physics selection and David for the response onthe multiplicity evaluation I would like to thanks Andreas Elena and Marie qualityassurance coordinator with whom I was in contact for my service task for their kindnessand efficiency during the two and a half years or I participated in the QA as well as fortheir understanding on the delays

Cette thegravese mrsquoa permis de mrsquoimmerger dans la communauteacute franccedilaise de la physiquehadronique notamment gracircce aux rencontre QGP France et je voudrais remerciertoutes les personnes avec qui jrsquoai pu avoir de bonnes discussions lors de ces rencontresnotamment les doctorants et post-doc que jrsquoai pu rencontrer Antoine Astrid AudreyBenjamin Emilie Gabriel Gabriele Jana Julien Lucile Maxime Michael et MohamadCette thegravese mrsquoa permis aussi de faire des rencontres enrichissantes durant les diverseseacutecoles que jrsquoai reacutealiseacutes et je souhaiterai remercier les doctorants qui y ont participeacute pourles bons moments passeacutes dans ces diverses eacutecoles

Bien sucircr je souhaite aussi remercier les doctorants qui ont cocirctoyeacute lrsquoIPNL durant cestrois anneacutees notamment Alexandre Biguet Anne-Laure Bertrand Ceacutecile Elvire Eme-line Franccedilois Guillaume Garilot Guillaume Victor Jean-Baptiste Joffrey Lola NicolasBaillot Nicolas Deutschmann Nicolas Galy Pierre Becker Reacutemi et Solegravene En plus desdoctorants que jrsquoai cocirctoyeacutes je souhaiterai aussi remercier Alain Cleacutement David GeoffreyHubert Martin Sylvie et Yoan pour les nombreuses pauses cafeacute pris ensemble durant cestrois anneacutees ainsi qursquoAntoine pour avoir accepteacute drsquoecirctre mon parrain pour ma thegravese

Merci aussi agrave Aureacutelie Camille Eacuteloiumlse Florian et Laurine pour tous les bons momentsque ce sois les midis en soireacutee durant des films ou des sessions jeux Merci aussi agrave Clairepour toutes ces discussions et soutiens mutuel pour nos thegraveses malgreacute le deacutecalage entrela France et le Breacutesil

Enfin jrsquoaimerais remercier ma famille pour leur soutiens durant toute ma formationuniversitaire ainsi que durant ma thegravese Je suis sucircr que mes grands-parents paternel auraieacuteteacute tregraves fiegravere de me voir arriver jusqursquoagrave ce diplocircme eux qui eacutetaient inquiets de savoir sijrsquoy arriverai ainsi que Christian et Thierry mes oncles auraient eacuteteacute fiegravere et auraient aimeacuteme voir agrave ce niveau

Reacutesumeacute

Ce manuscrit sur mon travail de thegravese commence par un premier chapitre sur les motiva-tions physiques du sujet eacutetudieacute tant sur le plan theacuteorique qursquoexpeacuterimental Dans le deux-iegraveme chapitre je traiterai du collisionneur de particules ayant produit les collisions danslrsquoexpeacuterience ALICE utiliseacutees durant lrsquoanalyse preacutesenteacutee dans ce manuscrit La secondepartie de ce chapitre est justement deacutedieacutee agrave lrsquoappareillage ALICE Le troisiegraveme chapitreporte sur la caracteacuterisation du jeu de donneacutees que jrsquoai exploiteacute ainsi que sur lrsquoeacutevaluationde la luminositeacute inteacutegreacutee correspondant agrave cet eacutechantillon Le quatriegraveme chapitre quant agravelui porte sur les simulations Monte-Carlo qui ont du ecirctre faites pour mener agrave bien cetteanalyse Le cinquiegraveme chapitre sur la meacutethodologie utiliseacutee pour extraire de nos don-neacutees les signaux drsquointeacuterecirct Dans lrsquoavant-dernier chapitre le sixiegraveme nous traiterons delrsquoeacutevaluation des quatre sources de systeacutematiques qui impactent notre analyse Le dernierchapitre traitera des reacutesultats que nous avons pu obtenir en termes de sections efficacesde production de meacutesons neutres leacutegers

Cadre Physique (chapitre 1)Le cadre theacuteorique englobant le travail preacutesenteacute dans ce document est la chromodynamiquequantique deacutecrivant lrsquointeraction forte lrsquoune des quatre interactions fondamentales quenous connaissons agrave lrsquoheure actuelle agissant sur les quarks et les gluons par eacutechangede gluons On verra que cette theacuteorie peut srsquoexprimer matheacutematiquement en termes dedensiteacute Lagrangienne De ce Lagrangien peut ecirctre extraite une symeacutetrie particuliegraverementinteacuteressante pour lrsquoeacutetude des meacutesons leacutegers neutres la symeacutetrie chirale qui sera traiteacutee endeacutetails dans ce chapitre introductif De la chromodynamique quantique peut ecirctre extraitun diagramme thermodynamique de la matiegravere hadronique dans lequel deux principalesphases sont visibles la phase ougrave la matiegravere hadronique se condense sous forme de hadronset la phase partonique ougrave est creacuteeacute un plasma de quarks et de gluons (QGP)

Expeacuterimentalement ce diagramme de phases peut ecirctre eacutetudieacute gracircce agrave des acceacuteleacuterateursde particules permettant de faire des collisions cible fixe etou en mode collisionneurDans la seconde partie de ce chapitre je commencerai par introduire quelques variablescineacutematiques drsquointeacuterecirct pour le domaine ainsi que deux concepts geacuteomeacutetriques qui sont lacentraliteacute de la collision deacutetermineacutee par la distance qui seacutepare les centres des deux noyauxet le plan de reacuteaction de la collision Une collision entre deux noyaux comporte plusieurseacutetapes chronologiques notamment la phase de QGP suivie par deux phases hadroniquesdomineacutees respectivement par des collisions ineacutelastiques et eacutelastiques cela engendre desproductions de particules tregraves diverses Dans la suite du chapitre seront parcourus tousles types de sondes inteacuteressantes pour lrsquoeacutetude des collisions drsquoions lourds jrsquoen profiteraipour faire un petit eacutetat de lrsquoart des mesures faites dans les diffeacuterentes voies drsquoobservationBien sucircr les reacutesultats montreacutes le sont seulement agrave titre drsquoexemple et pas de maniegravereexhaustive

La derniegravere section sur les reacutesultats expeacuterimentaux est focaliseacutee sur la productionde dimuons de basses masses dans ALICE qui fait lrsquoobjet de lrsquoeacutetude rapporteacutee dans ce

viii

manuscrit Dans les preacuteceacutedentes eacutetudes lrsquoaccent eacutetait mis sur le meacuteson φ qui est agrave lrsquooriginedu signal le plus facilement observable dans la reacutegion des basses masses Dans notre caslrsquoeacutetude a eacuteteacute porteacutee sur les meacutesons η ρω et φ car la statistique disponible dans le lotde donneacutees eacutetudieacute est suffisante pour extraire les signaux correspondants

LHC et ALICE (chapitre 2)La premiegravere partie du chapitre 2 sera consacreacutee au LHC notamment au complexedrsquoacceacuteleacuterateurs permettant drsquoinjecter au sein du LHC des noyaux ou des protons Onen profitera pour eacutevoquer les sceacutenarios futurs agrave relativement court terme pour le LHC etpour finir cette courte partie les programmes drsquoions lourds au CERN et plus geacuteneacuteralementdans le monde

La seconde partie du chapitre est deacutedieacutee au deacutetecteur ALICE Cette partie peut ecirctregrossiegraverement coupeacutee en deux parties la premiegravere deacutedieacutee au deacutetecteur actuel et son fonc-tionnement la seconde au programme drsquoameacutelioration qui doit deacutebuter agrave la fin du Run 2du LHC

Luminositeacute et Jeu de Donneacutees (chapitre 3)Dans ce chapitre deux points seront eacutevoqueacutes Le premier porte sur les conditions expeacuteri-mentales pour les donneacutees proton-proton agrave 13 TeV prises en 2016 utiliseacutees dans lrsquoanalysedeacutecrite dans ce manuscrit Le second porte sur lrsquoeacutevaluation de la luminositeacute inteacutegreacuteeCette mesure nous permet drsquoeacutevaluer des sections efficaces de production agrave partir des tauxde production connaissant la section efficace associeacutee agrave la condition de deacuteclenchement debiais minimal de lrsquoexpeacuterience et le nombre drsquoeacuteveacutenements de biais minimal eacutequivalent aujeu de donneacutees consideacutereacute dans lrsquoanalyse Ce chapitre ne traitera pas de lrsquoeacutevaluation decette section efficace de biais minimal qui fait lrsquoobjet drsquoune eacutetude agrave part entiegravere non dis-cuteacute dans ce manuscrit et qui sert agrave toutes les analyses Cette section traitera en deacutetailsde la proceacutedure permettant drsquoavoir le facteur de conversion entre le nombre drsquoeacuteveacutenementsanalyseacutes et le nombre eacutequivalent drsquoeacuteveacutenements de biais minimal

Simulations Monte-Carlo (chapitre 4)Ce chapitre est structureacute en deux parties la premiegravere se focalisant sur les meacutesons neutresleacutegers et la deuxiegraveme sur les simulations des processus de charme et beauteacute ouverte

Dans la partie sur les meacutesons on commencera par donner quelques geacuteneacuteraliteacutes surces particules ainsi que sur le geacuteneacuterateur employeacute dans les simulations Puis on traiteradeux cas drsquointeacuterecirct Le premier cas concerne les processus faisant intervenir trois particulesdans lrsquoeacutetat final de la deacutesinteacutegration (deacutesinteacutegration Dalitz) en mettant lrsquoaccent sur leurfacteur de forme Le second cas quandt agrave lui correspond aux deacutesinteacutegrations agrave deuxcorps dans les canaux dileptoniques et plus particuliegraverement dans celui dimuonique

La seconde partie du chapitre est consacreacutee aux dimuons venant des deacutesinteacutegrationsdes saveurs lourdes ouvertes Un dimuon venant des saveurs lourdes ouvertes est deacutefini

ix

comme deux muons produits durant les chaicircnes de deacutesinteacutegration drsquoune paire quark anti-quark charmeacutes ou beaux On verra dans cette section qursquoun impact visible sur le spectreen masse deacutecoule de la distribution cineacutematique initiale du quark beau ou charmeacute gracircceaux comparaisons que nous avons faites avec des simulations utilisant les distributionscineacutematiques de PYTHIA6 et de FONLL Le dernier point eacutevoqueacute dans ce chapitre concernela longueur de chaicircne de deacutesinteacutegration des hadrons charmeacutes et beaux car nous sommesinteacuteresseacutes agrave reproduire les dimuons venant des paires de charme ou de beauteacute qui sontcorreacuteleacutes Une hypothegravese que nous pouvons faire est que plus une chaicircne de deacutesinteacutegrationest longue plus la correacutelation reacutesultante de la paire est amoindrie On montrera que leprofil de longueur de chaicircne de deacutesinteacutegration possegravede une structure relativement complexeet qursquoil y a un impact sur le spectre en masse en ne consideacuterant qursquoun certain intervallede longueur de deacutesinteacutegration

Extraction du Signal (chapitre 5)Dans ce chapitre deux points seront eacutevoqueacutes le premier sera lrsquoeacutevaluation et la soustractiondu bruit combinatoire le second portera sur la proceacutedure utiliseacutee pour extraire le signal

La composante de bruit combinatoire dans les dimuons de signes opposeacutes aussi appeleacutebruit non-correacuteleacute provient de la meacutethode de construction des dimuons Cette meacutethodeneacutecessite la creacuteation de toutes les paires de dimuons possibles dans un eacuteveacutenement Poureacutevaluer cette composante nous employons la technique du mixage drsquoeacuteveacutenements crsquoest-agrave-dire que nous creacuteons agrave lrsquoaide des donneacutees un lot de dimuons qui par construction serontnon-correacuteleacutes en formant chaque dimuon par combinaison drsquoun muon drsquoun eacuteveacutenement avecun muon drsquoun autre eacuteveacutenement La distribution ainsi obtenue est normaliseacutee agrave partir desdistributions de dimuons de mecircmes signes Cette proceacutedure agrave eacuteteacute valideacutee agrave lrsquoaide desimulations Monte-Carlo Une fois la soustraction du bruit faite pour chaque intervalleen pT et y consideacutereacute dans notre analyse nous pouvons passer agrave lrsquoextraction du signal

Pour extraire le signal drsquointeacuterecirct de notre spectre de dimuons correacuteleacutes nous utilisonsune proceacutedure drsquoajustement par minimisation du χ2 Cette proceacutedure est baseacutee sur unefonction servant agrave lrsquoajustement qui est composeacutee des distributions en masse des pro-cessus hadroniques composant notre cocktail hadronique Nous verrons notamment parquel moyen nous arrivons agrave reacuteduire le nombre de degreacutes de liberteacute de notre fonction enasservissant certaines composantes agrave drsquoautres Une grande partie de ce point est consacreacuteeau traitement du continuum correacuteleacute et aux meacutethodes permettant de deacutecrire la forme dela fonction modeacutelisant le continuum correacuteleacute

Eacutevaluation des Systeacutematiques (chapitre 6)Ce chapitre est diviseacute en quatre parties une pour chaque contribution agrave la systeacutematiquede notre analyse

La premiegravere partie traitera de la systeacutematique sur lrsquoextraction du signal et notammentsur lrsquoeacutevaluation de la systeacutematique sur tous les choix que nous avons faits pour reacutealisernotre ajustement Pour cela un ou plusieurs tests sont faits en modifiant agrave chaque foisun seul paramegravetre par rapport agrave notre ajustement de reacutefeacuterence Une fois tous les tests

x

reacutealiseacutes pour un intervalle en pT-y consideacutereacute dans cette analyse on eacutevalue par la meacutethodede deacuteviation standard lrsquoerreur systeacutematique qui en reacutesulte

Les autres parties traiteront de la systeacutematique lieacutee agrave lrsquoestimation du produit delrsquoacceptante geacuteomeacutetrique et de lrsquoefficaciteacute de reconstruction notamment le choix de lrsquoinputcineacutematique pour les simulations Monte-Carlo lrsquoincertitude sur lrsquoefficaciteacute du systegraveme dedeacuteclenchement et sur lrsquoefficaciteacute du systegraveme de trajectographie

Reacutesultats (chapitre 7)Dans ce dernier chapitre avant de parler des reacutesultats nous discuterons la correction dusignal extrait des distributions de masse invariante reconstruit pour lrsquoestimation de lasection efficace de production Nous passerons ensuite aux reacutesultats en preacutesentant et endiscutant la deacutependance en pT et y de la section efficace de production des meacutesons ηρω et φ Les reacutesultats obtenus dans cette analyse seront compareacutes aux preacutedictions desmodegraveles PYTHIA et PHOJET et aux reacutesultats disponibles dans ALICE agrave drsquoautres eacutenergies

Table of contents xi

Table of contents

1 Physics Motivations 111 Theoretical Baseline 1

111 Quantum ChromoDynamics (QCD) 3112 Chiral Symmetry 6113 Hadronic Matter mdash Quark-Gluon Plasma (QGP) 11

12 Heavy-Ion Physics Experimental Program 12121 Relevant Kinematic Variables 13122 Collision Geometry 14123 Evolution of a Heavy-Ion Collision 15124 Experimental Observables of the QGP 16125 Proton-Proton Collisions 22

13 Low-Mass Dimuon Measurements in ALICE 23

2 ALICE at the CERN LHC 2921 The Large Hadron Collider 29

211 The CERN accelerator complex 29212 The LHC schedule 30213 The Experimental Heavy-Ion Program 32

22 A Large Ion Collider Experiment (ALICE) 33221 The Central Barrel 34222 The Forward Detectors 36223 The Muon Spectrometer 38224 The ALICE software framework 40225 The ALICE Upgrade 41

3 Data Sample Selection and Integrated Luminosity Evaluation 4531 Data Sample Event and Track Selection 4532 Integrated Luminosity Evaluation 46

321 F inorm Calculation 47

322 The MB Trigger Cross Section 50323 Lint Evaluation 51

4 Monte Carlo Simulations 5341 Light-Meson Decays 53

411 Kinematical Distributions 54412 Dalitz Decays 54413 Two-Body Decays 57

42 Dimuons from Open Heavy-Flavor Decays 60421 PYTHIAndash FONLL Comparison 61422 Decay Chain Length in the Open Heavy-Flavor Processes 62

xii Table of contents

5 Signal Extraction 6551 Combinatorial Background Evaluation and Subtraction 65

511 The Event Mixing Technique 66512 Monte Carlo Validation of the Event Mixing Technique 67513 The Combinatorial Background Estimation 68

52 Invariant Mass Fit Procedure 70521 Specific Constraints on the Hadronic Cocktail Components 71522 Correlated Continuum Treatment 72523 A Few Examples of Hadronic Cocktail Fits 76

6 Systematics Evaluation 7961 Systematics on the Signal Extraction 80

611 Relative Branching Ratio of two-body and Dalitz Decays for the ηand ω Mesons 80

612 σηprimeσφ Cross-Section Ratio 80613 σρσω Cross-Section Ratio 81614 Upper limit of the fit 81615 The correlated continuum shape 81616 Systematic Uncertainty Computation 82

62 Systematics from the MC input 8263 Systematics on Trigger Efficiency 83

631 Evaluation of the Trigger Response Function 83632 Results 84

64 Systematics on Tracking Efficiency 85641 Preliminary Check 85642 Tracking Efficiency Evaluation 86643 MC parametrization 88644 Results 89

65 Summary of Systematic Uncertainty 89

7 Light Neutral Meson Production 9171 Estimation of the Number of Generated Mesons 91

711 The Two-Body Decay Case 91712 The Dalitz Decay Case 92

72 Cross-Section Production for Light Neutral Mesons 93721 Double-Differential η Meson Production 93722 ρω Meson Production 94723 Double-Differential φ Meson Production 98

Conclusions 105

A List of Runs 107

B Raw-Background Comparison mdash figures 111

C Hadronic-Cocktail fits mdash figures 123

Table of contents xiii

Bibliography 135

Chapter 1

Physics Motivations

Summary11 Theoretical Baseline 1

111 Quantum ChromoDynamics (QCD) 3112 Chiral Symmetry 6113 Hadronic Matter mdash Quark-Gluon Plasma (QGP) 11

12 Heavy-Ion Physics Experimental Program 12121 Relevant Kinematic Variables 13122 Collision Geometry 14123 Evolution of a Heavy-Ion Collision 15124 Experimental Observables of the QGP 16125 Proton-Proton Collisions 22

13 Low-Mass Dimuon Measurements in ALICE 23

11 Theoretical BaselineThe theoretical framework underlying the subject of the present thesis is the StandardModel of particle physics (SM) The SM gathers the theories describing the electromag-netic weak and strong interactions as well as Higgs sector providing at the same timea classification of all the subatomic particles known in terms of matter constituents andgauge bosons see figure 11 It was developed throughout the latter half of the 20th cen-tury the current formulation having been finalized in the mid-1970s upon experimentalconfirmation of the existence of quarks Since then discoveries of the Wplusmn and Z0 bosons(1983) the top quark (1995) the tau neutrino (2000) and the Higgs boson (2012) havegiven further credence to the Standard Model [1]

Each elementary interaction in the SM is characterized by an interaction range anda set of gauge bosons carrying the interaction charge It should be noted that the SMdescribes the weak and electromagnetic interactions as two different aspects of a singleelectroweak interaction

bull The weak interaction has a very small range of the order of 10minus18 m and is medi-ated by the Z0W+ and Wminus bosons This interaction affects all known elementaryfermions

2 Chapter 1 Physics Motivations

bull The electromagnetic interaction is characterized by an infinite range and affectsany particle having a non-zero electric charge The associated gauge boson is thephoton

bull The strong interaction acts at small distances having a range of the order of 10minus15 mat this range the strong interaction dominates over the other elementary interac-tions The strong interaction is mediated by the exchange of massless gauge bosonscalled gluons that interact with quarks anti-quarks and other gluons via a chargecalled color charge The theoretical framework for the strong interaction is givenby the theory of Quantum Chromodynamics described in more details in the nextsection

12e neutrino

νe

minus1

12

510999 keV

electron

e

RGB23

12

22+06minus04 MeV

up

uRGB

minus13

12

47+05minus04 MeV

down

d

12micro neutrino

νmicro

minus1

12

105658 MeV

muon

micro

RGB23

12

127 plusmn 003 GeV

charm

cRGB

minus13

12

96+8minus4 MeV

strange

s

12τ neutrino

ντ

minus1

12

177686 plusmn 016 MeV

tau

τ

RGB23

12

160+5minus4 GeV

top

tRGB

minus13

12

418+004minus003 GeV

bottom

b

plusmn1

1

80385 plusmn 0015 GeV

Wplusmn1

911876 plusmn 00021 GeV

Z

1photon

γ

color

1gluon

g0

12509 plusmn 024 GeV

Higgs

Hst

rong

inte

ract

ion

elec

trom

agne

ticin

tera

ctio

n

weak

inte

ract

ion

6qu

arks

(+6

anti-

quar

ks)

6le

pton

s(+

6an

ti-le

pton

s)

12 fermions(+12 anti-fermions)

13 bosons

Matter Constituents Gauge BosonsGoldstone

bosons

1st 2nd 3rd generation

1

Figure 11 Standard Model of particle physics and the different families of matter

11 Theoretical Baseline 3

111 Quantum ChromoDynamics (QCD)The Quantum ChromoDynamics (QCD) is the theory describing the hadronic physicsphenomena in the framework of the SM For this reason QCD is needed to correctlydescribe and interpret the observations in experiments involving high-energy hadronicinteractions like ALICE at the LHC

The color charge of the QCD can have three different values (red green and blue) aswell as the corresponding anti-colors This determines a part of the mathematical struc-ture of QCD based on the special unitary group of degree 3 mdash the Lie group SU(Nc=3)cThe complete mathematical structure of QCD is based on the Lorentz group L = SO(1 3)for the space-time transformations (gluons are in the vector representation and quarksin the spinor one) a gauge symmetry SU(Nc = 3)c an approximate light flavor symme-try SU(Nf = 3)f (this symmetry is not relevant even approximately for the remaining3 heavy flavors) The introduction of a three-color charge allowed at the beginning ofthe development of the QCD for the reconciliation of the observation of the spin-3

2 ∆++

baryon composed of three up quarks in the same spin state with the Pauli exclusionprinciple

The QCD Lagrangian LQCD

In the Quantum Field Theory formalism of particle physics any theory can be expressedin terms of a Lagrangian The mathematical expression of the Lagrangian density ofQCD1 is

LQCD =flavorssumf

qc1f (ipartmicroγmicroδc1c2 minusmfδc1c2) qc2

f

+flavorssumf

qc1f gsA

amicrotac1c2γ

microqc2f minus

14G

microνa G

amicroν + LCP

(11)

(Besides the explicit flavor summation each index when repeated twice indicates asummation on this index) In equation (11) micro ν are Minkowski indexes ranging from 0to 3 the qcf spinor represents the quark field of flavor f and color c (the Dirac index ofquark fields and γ-matrices are not written explicitly for convenience) mf is the massof a quark of flavor f gs is linked to the coupling constant of the theory αs = g2

s4π(after quantification and renormalization αs becomes a running coupling constant alsoquantification requires the introduction of ghost fields) the gluon fields Aamicro are Lorentzvectors Gmicroν

a is the gluon strength tensor and the ta matrices (generators of SU(Nc=3)c)are defined after the Gell-Mann matrices ta = λa2

The first term of LQCD

Lfree q =flavorssumf

qc1f (ipartmicroγmicroδc1c2 minusmfδc1c2) qc2

f = q (ipart minus mf ) q (12)

is a free Lagrangian representing the propagation of free quarks m representing thediagonal quark mass matrix

1 By language abuse the QCD Lagrangian density is simply named QCD Lagrangian

4 Chapter 1 Physics Motivations

The second term

Lint =flavorssumf

qc1f gsA

amicrotac1c2γ

microqc2f = gsqAq (13)

encodes the minimal (or Yukawa) coupling describing the interaction of the quark fieldswith the gluons

The third term of LQCD involvesGamicroν the gluon strength tensor which can be expressed

asGamicroν = partmicroA

aν minus partνAamicro + gsf

abcAbmicroAcν (14)

The fabc coefficients are the structure constants of SU(3) The first part of the tensor inequation (14) partmicroAaν minus partνA

amicro describes the gluon kinematics in analogy to the kinematics

description of photons in quantum electrodynamics (QED) The last term gsfabcAbmicroA

cν is

specific to QCD and describes the gluon auto-coupling due to the fact the QCD is anon-Abelian theory

The last term in equation (11) LCP is related to a possible violation of the CP-symmetry (due to a breaking of T symmetry and the conservation of the CPT symmetry)in the QCD sector This term is defined as

LCP = θg2s

32π2 GamicroνG

microνa (15)

where G is the dual of GGamicroν = 1

2εmicroναβGαβa (16)

and εmicroναβ is the antisymmetric Levi-Civita pseudo-tensor The θ parameter which wouldtake a non-zero value in case of CP-violation of LQCD can be experimentally accessed bymeasuring the electric dipole momentum of the neutron Its value compatible with zerois currently not explained by the theory [2 3]

The QCD Running Coupling Constant αs

By using the perturbative-QCD (pQCD) and the renormalization group equation [4] it ispossible to extract a running coupling constant αs depending on the momentum transferQ and on a parameter ΛQCD establishing the scale at which the perturbatively-definedcoupling would diverge At first order of perturbation theory αs can be expressed as

αs(Q2) = 12π

(11Nc minus 2Nf ) ln(

Q2

Λ2QCD

) (17)

where Nc is the number of colors (3) Nf is the number of light flavors respecting mq Q

and ΛQCD asymp 200 MeVFigure 12 shows the excellent agreement between available measurements of αs(Q2)

and the pQCD theoretical prediction beyond first order According to the value of thetransfer momentum Q two regimes of QCD can be defined for values of the transfermomentum Q above Q asymp 1 GeV (of the order of the nucleon mass) implying Q ΛQCD(or for distances well below 1 fm corresponding to the nucleon size) QCD is in the regime ofasymptotic freedom for Q 1 GeV QCD behavior is dominated by the color confinementmechanism

11 Theoretical Baseline 5

Figure 12 Summary of measurements of αs as a function of the momentum transfer Q and thepQCD prediction [4]

Asymptotic Freedom

In the large momentum transfer region Q ΛQCD or at small distance the decreasingof the coupling constant αs reflects the fact that the particles interacting over shortdistances 1 fm (the typical size of the nucleon) can be treated asymptotically as quasi-free particles This allows one to use a perturbative approach in performing calculationsbased on series of αs powers Let us notice that asymptotic freedom does not mean thatquarks are not interacting at all in high-energy collisions (the freedom is only asymptotic)Indeed it has been shown that at RHIC energy a strongly interacting QGP (s-QGP) iscreated

Color Confinement

Figure 13 Sketch of twoquark separation

In the small momentum transfer region or large distancethe coupling constant perturbatively diverges The physicalinterpretation for this phenomenon is the color confinementA schematic explanation of this phenomenon is the followingif it was possible to hold two color charges (for example twoquarks) and pull them part the energy density would con-centrate into a flux tube due to the non-Abelian characteris-tics of QCD (differently to QED) The energy would increasewith the separation until it reaches a threshold above whichpair creation is possible Figure 13 sketches this effect known as string breaking This isthe reason why in vacuum it is not possible to observe directly one isolated quark and allof them are found in composite particles named hadrons the color charge of hadrons iszero (hadrons are ldquocolorlessrdquo or ldquowhiterdquo) as the colored flux tube wraps within the hadronitself and can be observed

6 Chapter 1 Physics Motivations

A simple modelisation of the potential V (r) between two quarks is given by the Cornellpotential [5]

V (r) = minusαsr

+ σr (18)

In equation (18) the first term models the asymptotic freedom with a Coulomb potential(this term is dominating at r rarr 0) and the second term (dominating when r rarr infin) iscalled the string potential with the string tension σ sim (260 MeV2)

Hadrons can be classified as

bull mesons composed of one quark and one anti-quark

bull baryons composed of three quarks

bull exotic states like the recently observed tetra-quark etc

112 Chiral SymmetryThe chiral symmetry is one of the two fundamental symmetries of QCD governing low-energy QCD (low-hadronic masses) and the properties of the transition between the par-tonic and the hadronic phases observed in heavy-ion collisions

The chiral symmetry can be conveniently introduced and discussed considering theway Lorentz transformations act on bosons and fermions To start this discussion let usconsider a massless universe To understand the properties of the Lorentz transformationof any quantum state one can decompose it into its fundamental building blocks calledchiral fermions χR (the right chiral fermion) and χL (the left chiral fermion) PhysicallyχR and χL are spinor fields (spin frac12) and the R and L indices denote the helicities ofthe states In a massless universe the helicity is a good quantum number there is noLorentz transformation that can change the ldquoorientationrdquo of the spin hence for any inertialobservers the measured helicity would be the same Since χR and χL are fundamentalstates when Lorentz transformations are considered one can build any spin state bymixing these building blocks mathematically the Lorentz group can then be describedas a SU(2)RotimesSU(2)L group whose fundamental representations2 are χR and χL

Let us now consider a massive fermion state obviously now two observers with differ-ent speed relative to the fermion will measure different projections of the spin along themomentum of the particle the helicity is no more a good quantum number The chiralfermions χR and χL can now transform into one another this mechanism is called thebreaking of the chiral symmetry As anticipated in the introduction of this section thissymmetry is crucial to understand the low-mass sector of QCD since it is dominated byhadronic states composed of almost massless quarks (namely u d s composing the light

2 To see why the SO(13) Lorentz group L can be described by the combination of two SU(2) groupsone has to remember that L contains three rotations (that gives one SU(2) group) and three boosts (thatcan be seen as rotation involving the time direction and an imaginary angle that gives another SU(2)group) Those two algebras are not independent (eg boost and rotation do not commute) but they canbe decoupled into SU(2)RotimesSU(2)L independent algebras

11 Theoretical Baseline 7

neutral meson studied in this thesis) compared to the typical scale of QCD ΛQCD (seetable 11)

u m = 22+06minus04 MeVc2 c m = 127plusmn 003 GeVc2 t m = 160+5

minus4 GeVc2

d m = 47+05minus04 MeVc2 s m = 96+6

minus4 MeVc2 b m = 418+04minus03 GeVc2

Table 11 Quark masses [4]

In the following we will explain with a very simple quark model some observablephenomena linked to the fundamental QCD chiral symmetry the non observation ofdegeneration in mass between the scalar and pseudo-scalar octet as well as the spontaneouschiral symmetry breaking related to the phase transition observed eg in LHC arounda temperature of 170 MeV

a A Lagrangian for a free massless quark

For one chiral quark χR the free Lagrangian is3

Lfree qR = iχdaggerRpart0χR + iχdaggerRminusrarrσ middotminusrarrpart χR (19)

the form of the Lagrangian being dictated by the usual constraints (Lorentz invariancehermiticity conservation laws) but for one quark flavor the state with opposite helicityalso exists in nature for one quark flavor one can write Lfree q = Lfree qR + Lfree qLThis can be conveniently written

Lfree q = qipartq (110)

where q is a Weyl spinor (4 component spinor)

q =[χRχL

] (111)

and the usual notation q = qdaggerγ0 (see chapter 32 of [1])

b Explicit breaking of the chiral symmetry in presence of a mass term

The Lagrangian of a free quark of mass m is

Lfree q = q (ipart minusm) q = L0 + Lm (112)

This Lagrangian contains a mass term which is explicitly written as

Lm = mqq = m(χdaggerRχL + χdaggerLχR

) (113)

The number of R (L) quarks in this system is given by

NRL = χdaggerRχR(χdaggerLχL

) (114)

3 We do not consider Majorana fermions in this manuscript

8 Chapter 1 Physics Motivations

Let us define a transformation belonging to the symmetry group U(1)RotimesU(1)L

χR rarr eiθR χR

χL rarr eiθL χL

Lfree q rarr L0 +m(ei(θLminusθR) χdaggerRχL + ei(θRminusθL) χdaggerLχR

) (115)

this symmetry is broken by the mass term as discuss previously when considering thecase of the boost of a massive fermion the number of R or L quarks is not the samefor all observers However this symmetry restricted to the case of θR = θL equiv θV is notbroken and is associated to the conservation of the fermion number This result in theUV (1) symmetry

q rarr eiθV q lArrrArr[χRχL

]rarr eiθV

[χRχL

] Lfree q rarr Lfree q (116)

The V stands for Vector (it is the conservation of the so-called vector current V micro = qγmicroq)For further convenience we also define UA(1) as the symmetry group with transformationgiven by θR = minusθL equiv θA the A stands for Axial (a transformation in UA(1) is thus givenby q rarr eiθAγ5 q)

c For more than one flavor

Finally let us consider the Lagrangian of a system composed by the two lightest flavorsu and d giving Nf = 2 (but this discussion could also be extended to a system includinga third flavor s light enough compared to ΛQCD)

Lfree light q = iqupartmicroγmicroqu + iqdpartmicroγ

microqd minusmuququ minusmdqdqd (117)

In this case one can introduce for convenience the iso-spinor ψ =(quqd

)

Lfree light q = ψ (ipart minus m0)ψ (118)

= iψpartmicroγmicroψ minus mu +md

2 ψψ minus mu minusmd

2 ψτ3ψ (119)

where m0 is the quark masses matrix τ3 is the iso-spin Pauli matrix (noted τ not toconfuse it with σ3 that acts on spinor index) For convenience let us also use

ψR equiv[quRqdR

]equiv

quR0qdR0

equiv PRψ (120)

wherePR = 1 + γ5

2 (121)

and the same for ψL wherePL = 1minus γ5

2 (122)

11 Theoretical Baseline 9

The symmetry we discussed in paragraph b is extended by adding a mixing ofthe flavor states This is what is usually called in the literature ldquochiral symmetryrdquoSUR(Nf )timesSUL(Nf )

The iso-spinor ψ = ψR + ψL transforms under the chiral symmetry as

ψ rarr eiminusrarrθR middotminusrarrt ψR + ei

minusrarrθL middotminusrarrt ψL (123)

where minusrarrt = ~τ

2 and minusrarrθRminusrarrθL isin (R3)2

As in the one flavor case the kinetic term

Lk = iψLpartmicroγmicroψL + iψRpartmicroγ

microψR (124)

is chiral invariant while the mass term is not However when the mass difference is zero(the so-called exact isospin limit) the SUV (Nf ) symmetry is exact

d The symmetry of the quark sector of QCD mdash the eightfold way

Let us consider only massless quarks (a good approximation for u d and s) giving Nf = 3and the light sector only

LQCD = Lfree light q + Lr (125)

where Lr incorporates the terms appearing in the second line of equation (11) as wellas any term relative to heavy quark Lr transforms trivially or in the same way as aLfree light q For this reason the chiral transformation of LQCD can be studied consideringLfree q only In this massless scenario the largest symmetry group for LQCD can be ex-pressed as G=UR(1)otimesUL(1)otimesSUR(Nf )otimesSUL(Nf ) = UR(Nf )otimesUL(Nf ) A transformationof this group is given by

ψ rarr eiθR t ψR + eiθL t ψL (126)

where t =(1~t

)and θ =

(θ ~θ

) This symmetry would allow one to classify light hadronic

states into double U(Nf = 3) multiplets (one for left-handed and one for right-handed)where scalar and pseudo-scalar members would be invariant under U(Nf = 3) rotationin the flavor space which implies the same mass This is not what is observed Atmost one sees multiplets (approximately) invariant under vector symmetry SUV (Nf = 3)rotation (see paragraph b ) for example the octet of pseudo-scalar mesons π K η andthe decuplet of baryons n p Λ etc

The chiral partner of the cited pseudoscalar meson octet is the scalar octet of the a0κ and σ meson the fact that no degeneracy in mass is observed between the members ofthe pseudoscalar octet and the members of the scalar one is linked to the G symmetrybreaking For convenience one can rewrite G = UR(Nf = 3)timesUL(Nf = 3) as

G = UV (1)otimes UA(1)otimes SUV (3)otimes SUA(3) (127)

where

bull UV (1) is the symmetry already discussed in paragraph b it is the conservation ofthe individual flavor quark number

10 Chapter 1 Physics Motivations

bull UA(1) was also introduced in paragraph b This group should be a symmetry in themassless scenario leading to the observation of mη = mηprime (one should see a nonetinstead of an octet of degenerated pseudoscalar mesons) [6] This is howevernot the case The more generally accepted explanation is that the gluon part Lr

of LQCD generates an explicit breaking of the UA(1) symmetry due to non-zeroquantum fluctuations in the gluon strength tensor sim 〈G2〉

G2 = GmicroνGmicroν (128)

bull SUV (3) this is the observed (approximate) symmetry between the masses of themembers of a multiplet4 This means that the SUV (3) symmetry is good enough toclassify hadronic states this corresponds to ldquothe eightfold wayrdquo

bull SUA(3) this group should be again a symmetry in a massless scenario one wouldthen observe a degeneracy between the scalar and the pseudoscalar meson octetThis is not the case because the chiral symmetry SUV (Nf )otimesSUA(Nf ) is sponta-neously broken (Goldstone mechanism) to SUV (Nf = 3) The π K η are the(almost) massless Goldstone bosons of this mechanism

e Spontaneous breaking of the chiral symmetry and phase transition

The Goldstone mechanism just mentioned when discussing the SUA(3) group can beunderstood in the framework of a quark model the Nambu-Jona-Lasinio model [78] withmassless quarks For two light flavors one has

LNJL = ψ (ipart)ψ +Gs

[(ψψ

)2+(ψiγ5~τψ

)2] (129)

where Gs is a coupling constant for four-quark contact interactions It mimics the shortrange strong interaction as a contact interaction This Lagrangian is chirally invariantsince the interaction term is built from a scalar ψψ and its pseudoscalar counterpart soas to be invariant

If the interaction term is sufficiently large (GsΛQCD2 sim 1) quarks can condense

(〈ψψ〉 6= 0) and equation (129) can be rewritten as

LNJL ψ(ipart + 2Gs〈ψψ〉

)ψ + middot middot middot (130)

The quantity mD equiv minus2Gs〈ψψ〉 acts exactly as a mass term (it is the so-called dynamicalmass) and spontaneously breaks the chiral symmetry

If temperature increases generally there will be a screening of the interaction and〈ψψ〉(T ) = 0 for T gt Tc where Tc is called the phase transition temperature the chiralsymmetry is said to be restored At approximately the same temperature the decon-finement occurs hence the high temperature phase is also known as the Quark GluonPlasma (or QGP) phase The fact that chiral symmetry restoration and deconfinementare occurring at almost the same temperature happens because in low-energy QCD thereis basically one scale only ΛQCD

4 The observed mass differences are not exactly zero because the u d s mass differences are notexactly zero (isospin limit)

11 Theoretical Baseline 11

minusrarrπσ

Ueff

A

B

a

minusrarrπσ

Ueff

b

minusrarrπσ

Ueff

c

1Figure 14 Effective potential as a function of ~πndashσ left to right going towards fully chirality restora-tion

If one takes σ sim ψψ and ~π sim ψiγ5~τψ the chiral symmetry restoration can be describedin the same way as the Goldstone mechanism related to the Higgs mechanism At lowtemperature one has a Goldstone effective potential Ueff (see figure 14 a) that has the well-known Mexican hat shape the ldquovacuumrdquo (relative to the expectation value 〈~π〉 = 0 = 〈σ〉)is in fact unstable The physical vacuum is located at the bottom of the potential on theso-called chiral circle As the temperature increases the chiral circle shrinks until the state〈~π〉 = 0 = 〈σ〉 is stable (see figure 14 c) this is the restoration of the chiral symmetry

The chiral symmetry restoration has an impact on the in-medium spectral functionsof hadrons the most easily accessible experimental observable related to this mechanismis the ρ meson thanks to its short life-time (13 fmc) allowing it to be produced anddecay inside the volume of the QGP typically obtainable in heavy-ion collisions

113 Hadronic Matter mdash Quark-Gluon Plasma (QGP)

As already remarked low-energy QCD mechanisms are driven by the same scale param-eter ΛQCD this is the reason why chiral symmetry restoration and color deconfinementhappen under the same thermodynamical conditions identifiable in the QCD phase dia-gram shown in figure 15

This schematic diagram presents two main regions The first one is the region atlow temperature and density where quarks and gluons are confined inside hadrons andthe chiral symmetry is broken The second region is characterized by large values oftemperature and or net baryon density where the relevant degrees of freedom are quarkand gluon and is a new state of matter the Quark Gluon Plasma (QGP) These tworegions are separated by a phase transition At vanishing net baryonic density (from 0 toan hypothetical critical point) this frontier is a smooth phase (ldquocross-overrdquo) transitionAt increasing value of net baryonic density beyond an hypothetical critical point thefrontier becomes a first order phase transition At extreme values of the net baryonicdensity and low temperature other hadron phases of the hadronic matter can be possibleas the hypothetic color superconducting phase proposed by some theoretical speculations

The only way to get experimental access to the QCD phase diagram in the regionof deconfinement under controlled conditions is to perform ultra-relativistic heavy-ioncollisions Different regions of the phase diagram can be covered by changing the center-

12 Chapter 1 Physics Motivations

Figure 15 Schematic QCD phase diagram as a function of temperature and net baryon density

of-mass energy of the collision as the energy increases the initial temperature of thesystem increases and its net baryonic density decreases At the high-energy frontier theexperiments carried at the Large Hadron Collider (LHC) at CERN and the RelativisticHeavy-Ion Collider (RHIC) at the BNL are suited to reproduce the conditions of hightemperature and low-net baryonic density present in the early Universe

In this QCD phase diagram there is a hypothetical Critical Point and this pointprovides a major research focus both theoretically and experimentally On the theory sidelattice QCD (LQCD) gives accurate results only at zero density It can be extrapolatedat finite density Another technique is the use of effective models as the NJL one [7] Onthe experimental side studies of heavy-ion collisions are done with several energies andion species (NA61 STAR PHENIX) and they probe different density regimes Finallycompact star observation may also give results about the zero temperature high densityphase of QCD

12 Heavy-Ion Physics Experimental ProgramThe experimental study of QGP needs this state of matter to be recreated in laboratoryAs we have seen in the previous section high density andor temperature are needed inorder to reach the conditions for the creation of the QGP state these conditions are metin ultra-relativistic heavy-ion collisions This experimental tool allows one to change theenergy density of the system by varying the size and the energy of the colliding nuclei

12 Heavy-Ion Physics Experimental Program 13

Several probes of the QGP exist which will be described later in this chapter the design ofa heavy-ion detector directly depends on the probes chosen for the experimental program

The relativistic heavy-ion experimental program started in the early 1980s at the BNLAGS [9] and CERN SPS [10] (collision energy per nucleon pair up to radicsNN asymp 20 GeV)and continues today both at the SPS and at the RHIC [11] and LHC [12] colliders whereenergies up to radicsNN = 02 TeV and 5 TeV are reached respectively

121 Relevant Kinematic Variables

Before discussing collision geometry and QGP probes we briefly introduced the mainkinematic variables of interest for heavy-ion physics and particularly for the study pre-sented in this manuscript

Transverse Momentum (pT) The kinematics of a particle can be described by anenergy-momentum quadrivector In the context of a high-energy experiment where aprivileged axis is defined by the beams the 3-momentum can be conveniently decomposedinto its longitudinal (pz) and transverse (pT) components The transverse momentum isinteresting for two reasons firstly the transverse degree of freedom is created during thecollision since the initial state is characterized only by the longitudinal degree of freedomof the colliding particles secondly the transverse momentum is invariant under Lorentzboosts along the z-axis allowing one to directly compare the pT distributions measuredin fixed-target and collider experiments

Rapidity (y) The longitudinal degree of freedom of a particle kinematics can be con-veniently expressed in terms of the rapidity variable y defined as

y = 12 ln

(E + pzcE minus pzc

) (131)

It can be shown that the rapidity is additive under Lorentz boosts along the z-axisthis allows one to directly compare the shape of the rapidity distributions measured infixed-target and collider experiments

Pseudo-Rapidity (η) In the ultra-relativistic regime where p m and E asymp p therapidity can be approximated by the pseudo-rapidity η

y = 12 ln

(E + cp cos θE minus cp cos θ

)asymp 1

2 ln(

1 + cos θ1minus cos θ

)= minus ln

[tan

(θ

2

)]equiv η (132)

The pseudo-rapidity is especially useful whenever the energy and the longitudinal mo-mentum pz are not available at the same time in this case the pseudo-rapidity providesan approximation of the rapidity based on the measurement of the polar angle θ only (theangle between the z-axis and the particle direction)

14 Chapter 1 Physics Motivations

Invariant Mass In case the particle of interest for a given analysis is not directlyobservable (because of its short life time) its kinematics can still be reconstructed byidentifying and measuring its decay products the quadrivectors of the daughters canbe composed to obtain the quadrivector of the mother particle from which can be easilyobtained its invariant massm2c4 = E2minusp2c2 In the specific case of the analysis presentedin this thesis the φ meson (as well as the other low-mass neutral mesons η ρ ω) hasbeen identified through its decay into two muons

122 Collision GeometryTo clearly interpret the observables in a heavy-ion collision one also needs to characterizeits geometry The two main geometric parameters characterizing a heavy-ion collision arethe centrality and the event plane

Centrality mdash The centrality is a concept related to the finite size of the collidingnuclei in fact heavy nuclei (like the lead nuclei accelerated at the LHC) can be regardedas extended objects consisting of several nucleons Some of these nucleons participate tothe collision and are called participants while the remnants do not interact and are calledspectators see figure 16-left

x

y

ΦRP

Figure 16 Schematic representation of a lead-lead collision

As it can be also seen in figure 16-left an impact parameter b can be identified whenlooking at a nucleus-nucleus collision in the transverse plane If this parameter is nullthe overlap between the two nuclei and the energy available in the overlapping volumeis maximal these collisions are classified as most central For larger impact parametersthe overlap region between the two nuclei and the energy available in the overlappingvolume become smaller these collisions are classified as semi-central semi-peripheral andperipheral for increasing values of b If the impact parameter is larger then two nuclearradii the collision is called ultra-peripheral and there is no hadronic interaction betweenthe two nuclei

The impact parameter in a heavy-ion collision is not directly measurable due to itsfemtoscopic size Yet b (so the centrality of the collision) can be estimated by quantifyingthe produced particle multiplicity since the two quantities are strongly correlated [13]An effective way to establish this correlation is provided by the Glauber Model [14]

In smaller collision systems like pp and p-Pb the measurement of the produced parti-cle multiplicity is still possible giving insight into the energy of the partonic interactions

12 Heavy-Ion Physics Experimental Program 15

involved in the collision (the so-called ldquoevent activityrdquo) However due to the loose corre-lation between this quantity and the geometry of the collision in such small systems [13]no geometrical interpretation can be established in this case

Event plane mdash In case the collision is not head-on it is possible to define the eventplane as a plane formed by the beam direction and the impact parameter The transverseprofile of this plane in non-central nucleus-nucleus collisions is represented in the rightpanel of figure 16 The determination of the event plane orientation event-by-event isimportant to characterize the azimuthal anisotropies observed in the measurement of theparticles produced in the collisions

123 Evolution of a Heavy-Ion CollisionFigure 17 illustrates the evolution of the hadronic collision in the two cases where theQGP is created (right side) or not (left side)

Figure 17 Space time evolution left-side without QGP right-side with QGP

Collisions with creation of QGP mdash In this case a dense and hot system of freepartons is created in the collision the typical size of the system is such that a ther-modynamical approach can be adopted and a medium temperature defined This sys-tem of deconfined quarks and gluons undergoes multiple interactions and the expansioncharacterized by a hydrodynamic-like collective expansion During this expansion thehadronization starts and there is a cooling of the system until the critical temperatureof the transition between the partonic and hadronic phases (Tc) is reached The coolingcontinues the medium is a hadronic gas until the temperature of chemical freeze-out(Tch) is reached (from above) beyond this point the inelastic interactions stop and the

16 Chapter 1 Physics Motivations

composition of hadronic species is fixed The cooling continues until the kinetic freeze-outis reached beyond this point the elastic interactions also stop and the hadrons fly to thedetectors with kinematic distributions characterized by a temperature Th

Collisions without creation of QGP mdash In this case the collision starts by a pre-equilibrium partonic phase which directly leads to the hadronic phase without passingthrough any significant hydrodynamic or thermodynamic evolution After the elasticinteractions between the hadrons stop the species and their kinematics are fixed

124 Experimental Observables of the QGPA variety of observables exists giving insight into the properties of the QGP each ob-servable providing a complementary piece of information

Bulk physics light-flavor radiation

Figure 18 Hadron yields from ALICE at theLHC and fit with the statistical hadronizationmodel [15]

The bulk radiation is mainly composed oflight-flavored hadrons (u d s quarks) Hav-ing a typical scale of 1 fm 1(200 MeV)these hadrons cannot exist inside the decon-fined medium For this reason the light-flavor radiation measured by the detector isformed at the transition between the QGPand the physical vacuum taking place at thecritical temperature Tc 160minus 180 MeVThis fact is confirmed by the good agreementbetween the measured relative abundancesof the main light hadron species (includinglight hypernuclei) and the prediction of a sta-tistical hadronization model with fixed ther-modynamical parameters at the transitionphase see figure 18

The global hydrodynamical flow drivingthe expansion of the deconfined medium in-

duces the radial flow characterizing the light-flavor radiation pT spectrum Experimen-tally it is possible to observe this radial flow by measuring the pT dependence of the yieldfor the various species of the bulk radiation an example is given in figure 19

Moreover if the initial conditions are not spherically symmetric as it is in fact the casein non-central heavy-ion collisions the difference in pressure in different spatial directionswill lead to a further ldquodirectedrdquo or ldquoellipticrdquo flow (characterized by the v2 parametersin the Fourier expansion of the azimuthal particle distribution) Since the elliptic flowdepends on the initial conditions of the expending medium (like the geometry and theshear viscosity) the flow studies of hadron spectra can provide information about theearlier pre-hadronic stages of the collisions For example figure 110 illustrates how the

12 Heavy-Ion Physics Experimental Program 17

Figure 19 Transverse momentum distributionsof the sum of positive and negative particles asmeasured by ALICE fitted individually with ablast wave function compared to RHIC dataand hydrodynamic models [16]

Figure 110 Elliptic flow coefficient of chargedparticle in PbndashPb collisions as a function of cen-trality compared to viscous hydrodynamic re-sults [1718]

shear viscosity (ηs) of the medium can be estimated by the analysis of the centralitydependence of the v2 parameter

Strangeness productionWithin the light-flavor radiation strangeness production plays a peculiar role since thereare no strange valence quarks in the initial state of the collision as opposed to u and dquarks yet they are sufficiently light to be abundantly created in the course of the colli-sions High-pT strangeness production happens either at the early stages of high-energycollisions in hard partonic scattering processes by flavor creation and flavor excitation(see Feynman diagrams in figure 111) or during the subsequent partonic evolution viagluon splittings Low-pT strangeness production is dominated by non-perturbative pro-cesses like string fragmentation however due to the heavier mass of the strange quark(95plusmn 5 MeVc2) than the u and d quarks the production of strange hadrons in fragmen-tation processes is suppressed in comparison to the production of hadrons containing onlyu and d quarks

q

q s

s g

g s

s

g

g s

s g

g s

s

Figure 111 Feynman diagrams in pQCD at first order for the strangeness production inside QGP

18 Chapter 1 Physics Motivations

Figure 112 pT-integrated yield ratios of strange and multi-strange hadrons to (π+ + πminus) as afunction of 〈dNchdη〉 measured in the rapidity interval |y| lt 05 [20]

An enhancement of strange hadron production was historically proposed [19] as anindication of the QGP formation the argument is that strangeness production would beenhanced by the large energy density available in the medium the enhancement scal-ing with the strangeness content of each hadron Figure 112 shows the ratio of strangehadrons over pions as a function of event multiplicity for pp p-Pb and Pb-Pb collisionsIn this figure one can appreciate the difference of the measured enhancement for strangehadrons containing different numbers of strange quarks Ks mesons and Λ baryons con-taining one strange quark Ξ baryons containing two strange quarks and Ω baryonscontaining three strange quarks

JetsIn high-energy collisions a significant production of hard partons is observed thehadronization of these partons produces a narrow cone of hadrons and other particlescorrelated together named jet In heavy-ion collisions jet measurements offer the pos-sibility to probe the deconfined medium by measuring the energy loss of the initial hardparton (jet quenching) and the modification of the jet cone structure and composition(jet broadening) Due to the high energy involved in the production of hard partons jetphysics in heavy-ion collision basically started at RHIC in 2000rsquo whereradicsNN values of theorder of 100 GeV became available for the first time Today jet physics in heavy-ion col-lisions profits from the larger energies available at the LHC implying larger cross-sectionsfor hard scattered partons and an extended range of jet energies

In figure 113 and 114 two examples of jet physics results in heavy-ion collisions are

12 Heavy-Ion Physics Experimental Program 19

Figure 113 The b-tagged jet RAA as a functionof Npart for two jet pT selections in Pb-Pb atradicsNN = 276 TeV in CMS [21]

(GeVc)Tassoc

p1 15 2 25 3 35 4 45

)shyπ

++

π)

(p

(p+

0

02

04

06

08

1

12

1415)plusmn lt η∆06 lt plusmn lt 052 φ∆Bulk Ratio (shy052 lt

lt 04)η∆ lt 052 shy04 lt φ∆Peak shy Bulk Ratio (shy052 lt

Pythia (Peak shy Bulk Ratio)

= 276TeV 0shy10 centralNN

sPbshyPb

lt 100 GeVcTtrig

50 lt p

ALIminusPRELminus15474

Figure 114 Ratio of proton to pion spectraas function of pT for the ldquobulkrdquo and ldquopeak-bulkrdquo [22]

shown In figure 113 the nuclear modification factor (RAA) of b-tagged jets is shown as afunction of Npart as measured by the CMS experiment at the LHC in Pb-Pb collisions atradicsNN = 276 TeV A clear decreasing trend for RAA is observed for increasing values of

Npart interpreted as a manifestation of the jet-quenching mechanism In figure 114 theproton-over-pion ratios in the bulk and in jet are shown as a function of pT measuredby ALICE in Pb-Pb collisions at radicsNN = 276 TeV The comparison of the measuredproton-over-pion ratio in jets (ldquopeak-bulkrdquo) with the prediction from PYTHIA suggeststhat no significant medium-induced modification of particle ratios is at play in jets

Heavy flavorsThe abundant production of c and b quarks at LHC offers a unique possibility to un-derstand the details of the energy loss thermalization and hadronization mechanismscharacterizing the interaction of heavy quarks with the medium

The energy loss can be studied through the measurement of the pT-dependence of thenuclear modification factor RAA for the various heavy flavor hadron species In figures 115and 116 the RAA averaged over the main non-strange D-meson species is compared withthe RAA of light-flavored mesons and (non-prompt) Jψ from B decays respectivelyprobing the suppression hierarchy RB

AA gt RDAA amp Rlight quarks

AA reflecting the different energyloss of light charm and beauty quarks Despite the large uncertainties the data suggesta similar energy loss for the charm and light quark a scenario also supported by sometheoretical models [23] The heavy quark hadronization mechanism in the medium can bestudied by comparing the production of various species of heavy flavor hadrons [2425]

QuarkoniaQuarkonia are resonance states of charm-anticharm (charmonia) or bottom-antibottom(bottomonia) pairs Quarkonium measurements provide information on the properties of

20 Chapter 1 Physics Motivations

Figure 115 Prompt D-meson RAA as a func-tion of pT compared to the pion and charged par-ticles RAA in the 0-10 centrality classes [26]

rangpart

Nlang0 50 100 150 200 250 300 350 400

AA

R

0

02

04

06

08

1

12

14

(empty) filled boxes (un)correlated syst uncertψ() 50shy100 for nonshyprompt J

|lt05y |clt16 GeVT

pD mesons (ALICE) 8lt

= 276 TeVNNsPbshyPb

rangpart

Nlang shifted by +10 in plusmnπ

(CMS)ψ Nonshyprompt J|lt12y |clt30 GeV

Tp 65lt EPJC 77 (2017) 252

50shy80

40shy5030shy40

20shy3010shy20

0shy10

|lt08y |clt16 GeVT

p (ALICE) 8ltplusmnπ

ALIminusPUBminus129313

Figure 116 Comparison of the average D-meson RAA in 8ltpT lt16 GeVc with chargedpions in the same pT range and Jψ from Bdecays in 65ltpT lt30 GeVc [27]

the medium in the early stages of heavy-ion collisions being sensitive to the in-mediumdissociation and recombination mechanisms for the various quarkonium states Quarko-nium dissociation was indeed proposed as a signature of the production of QGP in heavy-ion collisions due to a color-screening effect [28 29] in analogy to the Debye-screeningin electrostatics coupled to a dynamical interaction of the heavy-quark pair with thesurrounding partons [3031]

Figure 117 Dimuon mass spectrum in the Υregion in Pb-Pb collisions at radicsNN = 502 TeVwith CMS experiment [32]

rangpart

Nlang0 50 100 150 200 250 300 350 400

AA

R

0

02

04

06

08

1

12

14-micro+micro rarr ψInclusive J

c lt 8 GeVT

p lt 4 y = 502 TeV 25 lt NN

sPb minusALICE Pb

c lt 8 GeVT

p lt 4 y = 276 TeV 25 lt NN

sPb minusALICE Pb

c gt 0 GeVT

p| lt 22 y = 02 TeV 12 lt |NN

sAu minusPHENIX Au

ALI-DER-112313

Figure 118 The participant number depen-dence of RAA for inclusive Jψ in ALICE in Pb-Pb collisions at radicsNN = 502 and 276 TeVand in PHENIX at forward rapidity in Au-Au atradicsNN = 200 GeV

12 Heavy-Ion Physics Experimental Program 21

The dissociation mechanism resulting in the suppression of the less bound quarkoniumstates is best illustrated in figure 117 showing the dimuon mass spectrum in the Υ regionmeasured by the CMS experiment with the Pb-Pb data at radicsNN = 502 TeV comparedto the expected yield in pp One can observe that the suppression of the Υ(3S) state isstronger than the one of the Υ(2S) with respect to the Υ(1S) due to the different bindingenergy of the two resonance states (sequential melting of quarkonium)

For the charmonium states a statistical recombination mechanism is expected to com-pete with dissociation for sufficiently large values of the cc cross-section expected forinstance in Pb-Pb collisions at the LHC energies The interplay of the suppression andrecombination mechanisms has indeed been proposed to explain the ALICE data for thecentrality dependence of the Jψ RAA in Pb-Pb at radicsNN = 502 and 276 TeV shown infigure 118 together with the PHENIX results in Au-Au collisions at radicsNN = 200 GeVFor 〈Npart〉 gt 120 the ALICE Jψ RAA shows no significant centrality dependence and isalmost a factor of 3 larger than the PHENIX data for the most central points no sizablerecombination mechanism being at play at RHIC energy Further insight on the role ofstatistical recombination in charmonium production at the LHC could come from thecomparison of the Jψ elliptic flow measurements with the theoretical models

Electromagnetic probesElectromagnetic radiation (real photons and dileptons from virtual photons) is emittedfrom a variety of processes prompt photons from initial hard scatterings thermal photonsand medium-modified ρ dileptons from the QGP phase real and dileptons from radiativedecays after hadronization The fact that electromagnetic radiation is emitted during thewhole evolution of the collision represents at the same time an advantage (for instancethe possibility of probing the entire lifetime of the fireball) and a drawback (the variouscomponents being hard to disentangle) Another advantage of electromagnetic radiationis that whenever emitted it is not affected during its propagation by the strong inter-action dominating inside the deconfined medium providing a clean probe of hadronicinteractions

Figure 119 shows the pT spectrum of real photons in Pb-Pb collisions atradicsNN = 276 TeV measured by ALICE for three centrality classes In all centrality

classes no evidence for medium influence is observed at high pT At low pT (gt 2 GeVc)on the contrary an excess of real photons with respect to pQCD real photon productionis observed for mid- and central collisions with a temperature of Teff asymp 300 MeV ex-tracted in central collisions [33] This excess might be related indeed to the productionof thermal photons from the QGP phase

Figure 120 shows the excess in the dimuon mass spectrum with respect tothe expected hadronic sources measured by NA60 in semi-central In-In collisions atradicsNN = 173 GeV compared to various theoretical scenarios This excess is domi-

nated by the medium-modified ρ line shape at low mass (gt 1 GeVc2) and by a thermalcontribution at intermediate mass ( 1 GeVc2) and its study allows one to shed lighton the relevant properties of QGP equation of state [34 35]

22 Chapter 1 Physics Motivations

Figure 119 Direct photon spectra in PbndashPbcollisions atradicsNN = 276 TeV for three central-ity classes compared to model in pp collisions atthe same energy scaled by the number of binarynucleon collisions for each centrality class [33]

Figure 120 Dimuon invariant-mass in semi-central In-In collisions with NA60 [34]

125 Proton-Proton Collisions

Proton-proton collisions present various aspects of interest in the context of heavy-ionphysics namely as a reference for heavy-ion observations test for pQCD calculationsinput for phenomenological non-perturbative models and environment for collectivity insmall systems

As a reference for heavy-ion collisions pp measurements are needed in order hot andcold nuclear matter effects to be properly disentangled respectively in nucleus-nucleusand proton-nucleus collisions This implies two necessities collecting pp reference dataat the same radicsNN energy as more complex collision systems and finding appropriatevariables which could relate pp pA and AA observations A primary example is givenby the nuclear modification factor (RAA) defined as the direct ratio of production cross-sections in AA or pA over the corresponding pp reference scaled by the number of binarycollisions for example to study the charged-particle production [36]

Proton-proton collisions are also an ideal environment for the study of hard and softprocesses in vacuum In the first case (jets Jψ Υ ) one has the possibility to testpQCD calculations in the second case constraints on phenomenological models can bederived in terms of kinematic distributions and production cross-sections [3738]

Finally it is possible to use pp collisions for studying the emergence of collective ef-fects in small systems This study is typically performed analyzing the data in classes ofcharged particle multiplicity the onset of collectivity being driven by the event activityIn this context the observation of collective effects in large-activity pp and p-Pb colli-sions showing striking similarities with those observed in Pb-Pb collisions represents anintriguing challenge for theoretical models [39]

13 Low-Mass Dimuon Measurements in ALICE 23

13 Low-Mass Dimuon Measurements in ALICEThis thesis work is focused on low-mass dimuon measurements in pp collisions atradics = 13 TeV For this reason it is interesting to report here about low-mass dimuon re-

sults and currently ongoing analyses in the other collision systems and energies availableLow-mass dimuon production is studied in ALICE in Pb-Pb collisions atradicsNN = 276 and502 TeV in p-Pb collisions at radicsNN = 502 and 816 TeV as well as in pp collisions atradics = 276 502 7 and 8 TeV Due to the favorable position of its two-body decay in the

low-mass dimuon region with no significant competing sources beyond the smooth cor-related continuum from open heavy flavors the φ-meson has been the privileged subjectof the low-mass dimuon analyses in the first years of LHC operation

Pb-Pb collisionsThe LHC provided Pb-Pb collisions in Run 1 at radicsNN = 276 TeV and in Run 2 atradicsNN = 502 TeVDue to the limited statistics of the Run 1 data the φ-meson study is limited to the

pT range from 20 to 50 GeVc for the dimuons in Pb-Pb collisions at radicsNN = 276 TeVsee figure 121 where the lower limit is imposed by the hardware trigger condition onsingle muons (pT 1 GeVc) and the upper limit is defined by the available statisticsThe analysis of the Run 1 low-mass dimuon data allowed the measurement of the nu-clear modification factor RAA of the φ-meson at forward rapidity in Pb-Pb collisions atradicsNN = 276 TeV shown in figure 122 together with the corresponding ALICE mea-

surement at mid-rapidity and the PHENIX measurement at mid-rapidity in Au-Au andCu-Cu collisions at radicsNN = 200 GeV As can be seen from the comparison of the twoALICE sets of points the RAA does not exhibit any significant dependence on the rapidityregion considered on the contrary the PHENIX points seem systematically higher thanthe ALICE ones although still compatible with the latter within the total uncertaintiesAll the data sets agree on the general decreasing trend of RAA as a function of 〈Npart〉

The larger statistics available from the first Pb-Pb data taking at radicsNN = 502 TeVof Run 2 (2015 a second one being foreseen for 2018) allows the analysis of φ-mesonproduction to be performed up to 7 GeVc starting again from 2 GeVc due to thehardware trigger condition The pT dependence of the φ-meson yield could be studied inseveral centrality classes as shown in figure 123 where the data points are fitted withthe power-law function

dNdpTprop pT[

1 +(pTp0

)2]n (133)

where n and p0 are the free parameters of the fit The centrality dependence of φ-mesonproduction is also studied by looking at the central-to-peripheral ratio RAA as a functionof 〈Npart〉 as shown in figure 124 this dependence suggests a general decreasing trendof RAA as a function of centrality

p-Pb collisionsThe LHC provided in Run 1 p-Pb collisions at radicsNN = 502 TeV and in Run 2 at

24 Chapter 1 Physics Motivations

Figure 121 φ-meson yield as a function of pT inPb-Pb collisions at radicsNN = 276 TeV in threecentrality classes and two rapidity regions [40]

Figure 122 φ-meson RAA as functionof 〈Npart〉 in Pb-Pb collision at radicsNN =276 TeV and Au-Au and Cu-Cu collisions atradicsNN = 200 GeV [40]

)c (GeVT

p

0 1 2 3 4 5 6 7 8

shy1 )c

(G

eV

T

pd

yd

φN

2d

6minus10

5minus10

4minus10

3minus10

2minus10

1minus10

1

10

210

Centr 0shy10 x 8 Centr 10shy20 x 2

Centr 20shy40 Centr 40shy60

Centr 60shy90 Power law

= 502 TeVNN

sPbshyPb

lt 4y25 lt

ALICE Preliminary

ALIminusPRELminus117465

Figure 123 φ yield as a function of pT for fivecentrality classes in Pb-Pb collisions at radicsNN =502 TeV [41]

rang part

N lang

0 50 100 150 200 250 300 350

AA

R

0

05

1

15 = 502 TeV

NNsPbshyPb

shymicro+micro rarr φ

lt 4y25 lt c lt 7 GeV

Tp2 lt

ALICE Preliminary

ALIminusPRELminus131928

Figure 124 φ nuclear modification factor Rcpas a function of Npart in Pb-Pb collisions atradicsNN = 502 TeV [41]

13 Low-Mass Dimuon Measurements in ALICE 25

radicsNN = 816 TeV Because of the different energy of the proton and Pb beams in

p-Pb collisions the nucleon-nucleon center-of-mass moves in the laboratory with a posi-tive rapidity in the direction of the proton beam The directions of the proton and Pbbeam orbits can be inverted during the p-Pb data taking periods allowing the ALICEmuon spectrometer to access a forward rapidity region when the proton beam is directedtowards the muon spectrometer (203 lt y lt 353) and a backward rapidity region whenthe Pb beam is directed towards the muon spectrometer (minus446 lt y lt minus296)

y

shy4 shy2 0 2 4

(b

)y

dφ

σd

0

005

01

015

02data

HIJING

DPMJET

=502 TeVNN

sALICE pshyPb

c lt 7 GeVT

p1 lt

ALI-PUB-94059

Figure 125 φ-meson cross-section as a func-tion of y in p-Pb collisions at radicsNN = 502 TeVand 10 lt pT lt 70 GeVc Predictions fromHIJING and DPMJET are also shown for com-parison

)c (GeVT

p

0 1 2 3 4 5 6 7

)shymicro

+micro

rarr φ

(F

BR

0

05

1

15

data

HIJING

DPMJET

=502 TeVNN

sALICE pshyPb

|lt353y296lt|

ALI-PUB-94063

Figure 126 φ-meson forward-backward cross-section ratio as a function of pT for 296 lt |y| lt353 in p-Pb collisions at radicsNN = 502 TeVPredictions from HIJING and DPMJET are alsoshown for comparison

Figure 125 reports the φ-meson cross-section as a function of y for p-Pb collisions atradicsNN = 502 TeV showing a clear asymmetry between the forward and backward regions

not reproduced by the predictions of HIJING and DPMJET also shown To establish a moredirect comparison of the φ-meson cross-section in the forward and backward regions thecross-section was extracted as a function of pT in the common |y| range 296 lt |y| lt 353in terms of the ratio RFB between the forward and backward cross-section shown infigure 126 The observation of RFB values significantly different than 1 is consistent withthe observation of the asymmetry in the y dependence of the cross-section reported infigure 125 No significant pT dependence of RFB is visible within statistical and systematicuncertainties

p-Pb data have also been taken in 2016 at radicsNN = 816 TeV with a total integratedluminosity larger than the one of the radicsNN = 502 TeV data taking (see table 22) Theanalysis of this data is currently ongoing and is expected to produce the first preliminaryresults in 2018

pp collisionsLow-mass dimuon data in pp collisions are available at several center-of-mass energiesradics = 276 7 and 8 TeV (data taken during the LHC Run 1) 502 and 13 TeV (data

taken during the LHC Run 2)

26 Chapter 1 Physics Motivations

pp results atradics = 276 TeV [13] are used as a reference for Pb-Pb collisions at

the same radicsNN Figure 127 shows the opposite-sign dimuon signal (after combinatorialbackground subtraction) integrated over the available pT and y ranges compared to theresult of the hadronic cocktail fit the good quality of the data-MC comparison leads toa robust extraction of the φ-meson signal Figure 128 shows the φ-meson differentialcross-section as a function of pT compared to the Levy-Tsallis function [42]

1pT

dNdpTprop1 +

radicpT2 +m2

φ minusmφ

nT

minusn (134)

with n and T as free parameters In figure 128 data are also compared to the predictionsby PHOJET and PYTHIA tunes ATLAS-CSC D6T Perugia0 and Perugia11 As one cansee a good agreement is found between predictions and data except for PYTHIA tunesPerugia0 and Perugia11 which underestimate the cross-section measurement

)2c (GeVmicromicroM

0 02 04 06 08 1 12 14

)2

c (

dim

uo

ns p

er

25

Me

V

micromicro

Md

Nd

0

05

1

15

310times

micromicro

rarrρ

0πmicromicrorarrω

micromicro

rarr φ

γmicromicrorarrrsquoηmicromicro rarr bb

γmicro

micro rarr

η

micromicro

rarr ω

micromicro rarr cc

= 276 TeVspp

lt 4y25 lt

c lt 5 GeV T

p1 lt

micromicro

rarr η

ALICE

ALI-PUB-94035

Figure 127 Dimuon opposite-sign mass spec-trum in pp collisions at

radics = 276 TeV af-

ter combinatorial background subtraction pT-and y-integrated data compared to the hadroniccocktail fit [13]

)c (GeVT

p

0 1 2 3 4 5

))c

(m

b(

Ge

V

Tp

dy

dφ

σ2

d

shy310

shy210

shy110

1 = 276 TeVsALICE pp

lt 4y25 lt

Data

PYTHIA ATLASshyCSC

PYTHIA D6T

PYTHIA Perugia0

PYTHIA Perugia11

PHOJET

LevyshyTsallis

ALI-PUB-94047

Figure 128 φ-meson cross-section as a func-tion of pT in pp collisions at

radics = 276 TeV

Predictions from PHOJET and PYTHIA are alsoshown for comparison as well as the result of afit with a Levy-Tsallis function [13]

Low-mass dimuon data taken in 2015 in pp collisions atradics = 502 TeV offer the

possibility to establish a data-based reference for Pb-Pb and p-Pb data at the sameenergy The opposite-sign dimuon signal in pp collisions at

radics = 502 TeV is shown

in figure 129 integrated over the available pT and y ranges compared to the resultof the hadronic cocktail fit the good quality of the data-MC comparison allows for arobust extraction of the φ-meson signal The pT-differential φ-meson cross-section couldbe extracted up to 6 GeVc as shown in figure 130 compared to different theoreticalmodels

Low-mass dimuon data in pp collisions atradics = 7 TeV allowed for the study of the pT-

differential ω and φ cross-sections The hadronic cocktail fit on the isolated opposite-signdimuon signal is shown in figure 131 The identification of the ω and the φ meson signals

13 Low-Mass Dimuon Measurements in ALICE 27

)2c (GeVmicromicroM

0 02 04 06 08 1 12 14

)2

c (

dim

uo

ns p

er

25

Me

V

micromicro

Md

Nd

1000

2000

3000

4000 = 502 TeVspp

lt 4 y25 lt c lt 7 GeV

Tp1 lt

γmicro

microrarr

η

micromicrorarrρ

micromicro

rarrω

0πmicromicrorarrωmicro

microrarr

φ

γmicromicrorarrrsquoη

cc

bb

γmicro

microrarr

η

micromicrorarrρ

micromicro

rarrω

0πmicromicrorarrωmicro

microrarr

φ

γmicromicrorarrrsquoη

cc

bb

ALICE Preliminary

ALIminusPRELminus131989

Figure 129 Dimuon opposite-sign mass spec-trum in pp collisions at

radics = 502 TeV af-

ter combinatorial background subtraction pT-and y-integrated data compared to the hadroniccocktail fit [41]

)c (GeVT

p

0 1 2 3 4 5 6 7 8

))c

(m

b(

Ge

V

Tp

dy

dφ

σ2

d

3minus10

2minus10

1minus10

1 = 502 TeVspp

ATLASshyCSCD6TPerugiashy0

Perugiashy11PhojetMonashshy2013

ALICE Preliminary

lt 4y25 lt

ALIminusPRELminus132725

Figure 130 φ-meson cross-section as a functionof pT in pp collisions at

radics = 502 TeV [41]

resulted in the measurements of the pT differential cross-section shown in figure 132 for theω-meson only calculation based of PHOJET and PYTHIA with ATLAS-CSC and D6T tunesfairly agree with the data while the Perugia0 and Perugia11 PYTHIA tunes underestimatethe cross-section by about a factor of 2 and 25 respectively (the same conclusions standfor φ-meson)

)2M (GeVc

0 02 04 06 08 1 12 14

)2

dN

dM

(p

air

s p

er

25 M

eV

c

0

1000

2000

3000

4000

cc

micro micro

rarr φ

micro micro

rarr ω

micro micro rarr ρ

γ micro

micro rarr

η

micro micro

rarr η

0π micro micro rarr ω

γ micro micro rarrrsquo η

lt 5 GeVct

1 lt p

= 7 TeVsALICE pp

25 lt y lt 4

ALIminusPUBminus26621

Figure 131 Dimuon opposite-sign mass spec-trum for pp collisions at

radics = 7 TeV after com-

binatorial background subtraction pT- and y-integrated sample compared to the result of thehadronic cocktail fit [43]

Figure 132 ω-meson cross-section as a func-tion of pT in pp collisions at

radics = 7 TeV com-

pared to the predictions of various phenomeno-logical models [43]

Finally low-mass dimuon data are also available in pp collisions atradics = 8 TeV This

28 Chapter 1 Physics Motivations

)2c (GeVmicromicroM

0 02 04 06 08 1 12 14

)2

c (

dim

uo

ns p

er

25

Me

V

micromicro

Md

Nd

0

2000

4000

6000

8000

10000

12000 ALICE Preliminary

s = 8 TeVradicpp

25 lt y lt 4

c lt 80 GevT

p15 lt

γmicromicro

rarr

η

γmicromicro rarrrsquo η0πmicromicro rarr ω

bb

micromicro

rarr ω micro

micro rarr φ

micromicro rarr ρcc

ALIminusPRELminus133143

Figure 133 Dimuon opposite-sign mass spec-trum in pp collisions at

radics = 8 TeV after com-

binatorial background subtraction pT- and y-integrated data compared to the hadronic cock-tail fit [41]

)c (GeVT

p

0 1 2 3 4 5 6 7 8

))c

(m

b(

Ge

V

Tp

dy

d φσ

2d

3minus10

2minus10

1minus10

1hEmpty

Entries 0

Mean x 0

Mean y 0

Std Dev x 0

Std Dev y 0

s = 8 TeVradicpp ATLASshyCSCD6TPerugiashy0Perugiashy11

PhojetMonashshy2013

ALICE Preliminary

lt 4 y25 lt

ALIminusPRELminus133207

Figure 134 φ-meson cross-section as a functionof pT in pp collisions at

radics = 8 TeV [41]

offers the possibility to enrich the study of light neutral meson production in pp collisionsas a function of

radics providing at a same time a useful reference for the p-Pb data at

the same radicsNN energy The available statistics larger than the one in pp collisions atradics = 7 TeV allows to extract the low-mass dimuon analysis up to pT = 80 GeVc On

the other side the higher single muon threshold implies that the analysis could only startfrom pT = 15 GeVc The pT- and y-integrated opposite-sign dimuon signal is shown infigure 133 with the associated hadronic cocktail fit Figure 134 shows the extracted φcross-section as a function of pT compared to three predictions of EPOS-LHC and PYTHIA-8with and without multiple parton interactions As one can see the EPOS-LHC predictionoverestimates the φ cross-section while the comparison to the PYTHIA-8 predictions seemsto favor a scenario including multiple parton interactions

Chapter 2

ALICE at the CERN LHC

Summary21 The Large Hadron Collider 29

211 The CERN accelerator complex 29212 The LHC schedule 30213 The Experimental Heavy-Ion Program 32

22 A Large Ion Collider Experiment (ALICE) 33

221 The Central Barrel 34222 The Forward Detectors 36223 The Muon Spectrometer 38224 The ALICE software framework 40225 The ALICE Upgrade 41

21 The Large Hadron ColliderThe Large Hadron Collider (LHC) straddling the FrenchSwiss border in average100 meter underground in a circular tunnel of some 27 km of circumference is as fornow the worldrsquos largest and most powerful particle collider It operates at the TeVenergy scale with nominal energy of 14 TeV (in pp collision) and 55 TeVnucleon pair(in Lead-Lead) foreseen to be achieved in 2018 To carry out this technical challengethe CERN machine engineers developed a new accelerating technique based on supercon-ducting magnets (NbTi) cooled down to a temperature below 2 K which can generatemagnetic fields up to 8 T Four main experiments have been installed within the LHCring namely ATLAS (A Toroidal LHC ApparatuS) CMS (Compact Muon Solenoid)LHCb (LHC-beauty) and ALICE (A Large Ion Collider Experiment) ALICE will bedescribed in more details in section 22

211 The CERN accelerator complexFigure 21 displays the LHC ring and the full complex of accelerators upstream the LHCFollowing a complete trip from the proton source to the final output within the LHCprotons are produced in the LINAC 2 and then injected in the BOOSTER (PSB forProton Synchroton Booster) first accelerator ring This accelerating stage increases the

30 Chapter 2 ALICE at the CERN LHC

Figure 21 The LHC and the CERN accelerator complex [44]

proton energy from 50 MeV to 14 GeV Once protons have reached the top PSB energythey are injected into the Proton Synchroton (PS) where their energy is ramped up to25 GeV and then into the Super Proton Synchrotron (SPS) (7 km in circumference) tothe nominal energy of 450 GeV The latter is the LHC injector and is used in parallel toprovide particle beam to other CERN experiments (for example NA61SHINE)

In the case of the LHC heavy ions runs the lead ions are firstly accelerated in aLINAC 3 then further accelerated in the Low Energy Ion Ring (LEIR) which increasesthe lead energy from 42 MeV to 72 MeVnucleon before injection in the PS The leadions are then accelerated and injected in the SPS and from there to the LHC

212 The LHC schedule

During the first LHC run (Run 1 2009ndash2013) several energies and three collision systems(pp p-Pb Pb-Pb) have been explored In pp collisions five different center-of-massenergies have been considered 09 236 276 7 and 8 TeV p-Pb and Pb-Pb collisionshave been measured at radicsNN = 502 TeV and radicsNN = 276 TeV respectively Run 1was followed by a first Long Shutdown (LS1) mainly dedicated to the upgrade of theaccelerator system mdash resulting in an increase of the collision energy from 7minus 8 TeV to13minus 14 TeV in proton-proton collisions (from 276 TeV to 502 TeV in Pb-Pb collisions)mdash and the completion of the detectors of some of LHC experiment (in the case of ALICEthe electromagnetic calorimeter and the Transition Radiation Detector were updated)Run 2 started in mid-2016 and is planned to last until the end of 2018 with pp collisionsdelivered at 502 and 13 TeV Pb-Pb collisions delivered at radicsNN = 502 TeV and p-Pbcollision delivered at radicsNN = 502 minus 8 TeV LS2 is foreseen to start at the beginningof 2019 ending in late 2020 during LS2 the installation phase of the ALICE upgrade

21 The Large Hadron Collider 31

program will take place During Run 3 pp and Pb-Pb collisions will be delivered atthe nominal LHC energy (14 TeV for pp and radicsNN = 55 TeV for Pb-Pb) and the firstPb-Pb data taking at high-luminosity will take place LS3 will be mainly devoted to theinstallation of the High-Luminosity LHC (HL-LHC) providing unprecedented luminositiesin pp collisions at the designed LHC energy During LS3 the CMS and ATLAS upgradeprograms will be finalize Run 4 will see the beginning of the HL-LHC program in ppcollisions and the continuation of the high-luminosity heavy ion program

Figure 22 LHC schedule for 2015 to 2035 [45]

a Delivered Luminosity Measurement in ALICE

In high energy physics the luminosity is an essential concept expressing the interactionrate normalized to the intensity of the interacting fluxes of particles In the specific caseof a collider with beam pulsing the luminosity is defined by equation (21) where Nb

is the number of particles per bunch nb is the number of bunches per beam frev therevolution frequency γ is the relativistic gamma factor εn the normalized transversebeam emittance βlowast the beam beta function at the interaction point (for more details seechapter 4 of [46]) and F the geometric luminosity reduction factor due to the crossingangle at the interaction point (IP) [47]

L = N2b nbfrevγ

4πεnβlowastF (21)

The luminosity determination in ALICE is based on visible cross section measurementsperformed during van der Meer (vdM) scans [48 49] In standard vdM scans the twobeams are moved across each other in transverse directions x and y The two scans are

32 Chapter 2 ALICE at the CERN LHC

performed separately and the visible cross section is given by the detectors used for thedefinition of the minimum bias triggering conditions typically the V0 and T0 in ALICE

213 The Experimental Heavy-Ion ProgramThe goal of the LHC heavy-ion program is to produce the hottest the largest and thelongest-lived volumes of QGP in laboratory and to provide a precise characterizationof this new state of matter For that nucleus-nucleus collisions (A-A) are delivered atenergies up to radicsNN = 55 TeV Proton-proton and proton-nucleus collisions are also partof the LHC heavy-ion program providing the needed baseline (in terms of vacuum-likecross-sections and cold nuclear matter effects) allowing for a correct interpretation of theobservations in A-A collisions

In addition to the LHC there are other experimental complexes developing specificheavy-ion programs The most important one is the experimental program implementedat the Relativistic Heavy Ion Collider (RHIC) [50] hosted at the Brookhaven NationalLaboratory (BNL) in Long Island (New York US) RHIC is a dedicated heavy-ion facilityand it has a large flexibility in the choice of both the nuclear species accelerated (fromprotons to Uranium) and the center-of-mass energy (in the range radicsNN = 75minus200 GeV)Four detectors are installed at RHIC one of them STAR still operates today whilePHOBOS BRAHMS and PHENIX completed there operations respectively in 2005 2006and 2016 At CERN a fixed-target heavy-ion program complementary to the LHC one isalso running at the SPS with the NA61SHINE experiment [51] currently performing asystematic scan both in beam energy (radicsNN = 45minus 173 GeV) and colliding system size

In addition to the upgrade of some of the existing experiments several new heavy-ionprograms are under discussion or already in preparation [52]

bull The NICA1 facility at JINR [53] will operate in collider mode in the center-of-massenergy range radicsNN = 4 minus 11 GeV and in fixed-target mode in the center-of-massenergy range radicsNN = 19minus 24 GeV

bull The FAIR2 [54] facility at GSI3 will provide fixed-target collisions in the center-of-mass energy range radicsNN = 2minus 29 GeV

bull The AFTER4 project [55] aiming at running a fixed-target heavy-ion program withthe LHC beams at a center-of-mass energy of radicsNN asymp 72 GeV

bull The NA60+ [5657] is a project of fixed-target experiment based at the SPS focusingon dimuon observables at a center-of-mass energy range radicsNN = 63 ndash 173 GeV

1Nuclotron-based Ion Collider fAcility2Facility for Antiproton and Ion Research3Gesellschaft fuumlr Schwerionenforschung mbH4A Fixed Target ExpeRiment at LHC

22 A Large Ion Collider Experiment (ALICE) 33

22 A Large Ion Collider Experiment (ALICE)

Figure 23 Scheme of the ALICE detector

ALICE is an experiment optimized for the study of the physics of strongly interactingmatter at extremely high energy density focusing in particular on the investigation of theQGP state and the characterization of its properties A key design consideration drivingthe developement of the ALICE detector is the possibility to study the most energeticPb-Pb collisions delivered by the LHC This is done by measuring the particles emergingfrom the interaction region it is achieved by ALICE by exploiting a rich variety of sub-detectors see figure 23 based on different technologies described in the following sections[58] Beyond the heavy-ion program ALICE is also interested in collecting data in proton-proton (pp) and proton-Lead (p-Pb) collisions where no large volumes of deconfinedmatter are supposed to be produced to be used as a reference for the Pb-Pb ones

In table 21 and table 22 the ALICE running conditions in the LHC Run 1 and Run 2respectively are summarized

System ECM [TeV] Year Delivered luminosity

pp

09 2009 196 microbminus1

236 2009 087 microbminus1

276 2011 46 nbminus1

2013 129 nbminus1

7 2010 05 pbminus1

2011 49 pbminus1

8 2012 97 pbminus1

p-Pb 502 2012 15 microbminus1

2013 0891 nbminus1 and 140 nbminus1

Pb-Pb 276 2010 9 microbminus1

2011 146 microbminus1

Table 21 Summary of Run 1 ALICE data taking considered for published or ongoing analyses [59]

34 Chapter 2 ALICE at the CERN LHC

System ECM [TeV] Year Delivered luminosity

pp

502 2015 14951 nbminus1

132015 694 pbminus1

2016 1335 pbminus1

2017 192 pbminus1

p-Pb 502 2016816 2016 868 nbminus1 and 124 nbminus1

Pb-Pb 502 2015 280 microbminus1

Table 22 Summary of Run 2 ALICE data taking considered for published or ongoing analyses [59]

221 The Central Barrel

The ALICE central barrel refers to the assembly of detectors installed around the inter-action point inside the L3 magnet These detectors are dedicated to the tracking andidentification of isolated charged particles and photons as well as to the reconstructionof jets

Inner Tracking System (ITS)

The Inner Tracking System (ITS) is the internal tracker of ALICE It is formed by sixcylindrical layers of silicon detector the innermost one having an internal radius of 39 cmlimited by the external radius of the beam pipe The radius of the outermost layer is430 cm The geometric parameters of the ITS are summarized in table 23

sub-system name layer technology r(cm) plusmnz(cm)

SPD 1 Pixel 39 1412 Pixel 76 141

SDD 3 Drift 150 2224 Drift 239 297

SSD 5 Strip 380 4316 Strip 430 489

Table 23 ITS Geometric features

The pseudo-rapidity coverage of the ITS is |η| lt 09 The six layers are grouped intosix groups of two layers each differing by the adopted technology The two innermost lay-ers are composed of silicon pixel detectors (SPD) the central one of silicon drift detectors(SDD) the two outermost are composed of silicon strip detectors (SSD) The ITS allowsthe position of the primary and secondary (from strange and charmed particles) verticesto be determined with a resolution better than 200 microm in rφ and 300 microm in z directionFurthermore it contributes to the particle identification complementing the informationprovided by the TPC especially for the low momentum particles (p lt 200 MeVc)

22 A Large Ion Collider Experiment (ALICE) 35

Time Projection Chamber (TPC)

The Time Projection Chamber (TPC) is the main detector of the central barrel It iscomposed of a 51 m long cylindrical drift volume of 90 m3 developing between an innerradius of 85 cm and an outer radius of 247 cm This volume is filled with NendashCO2 and isdivided into two parts by the central cathode which is kept at minus100 kV The end platesare equipped with multiwire proportional chambers (MWPC) As the ITS the pseudorapidity coverage is |η| lt 09 In addition to tracking the TPC provides charged-particleidentification via measurement of the specific ionization energy loss dEdx Due to theadopted technology and the large size the TPC is the slowest detector of ALICE thuslimiting the interaction rate that can be supported

Transition Radiation Detector (TRD)

The Transition Radiation Detector (TRD) is composed of eighteen super-modules dividedinto thirty modules arranged in six radial layers and five sectors along the beam directionThe TRD has full azimuth coverage and spans the pseudo-rapidity region |η| lt 09This sub-detector provides particle identification for electrons of momentum larger than1 GeVc

Time-Of-Flight (TOF)

The Time Of Flight (TOF) detector allows the particle time-of-flight to be measuredThe TOF coverage is |η| lt 09 in full azimuth It has a modular structure organized intoeighteen sectors in azimuth and five modules along the beam axis The whole detectoris inscribed in a cylindrical volume with an internal radius of 370 cm and an externalone of 399 cm The TOF has an intrinsic time resolution of about 50 ps thanks to thetechnology of Multi-Resistive Plate Chambers (MRPC)

High-Momentum Particle Identification Detector (HMPID)

The ALICE HMPID is based on proximity focusing Ring Imaging Cherenkov (RICH)counters and consists of seven modules mounted in an independent support cradle fixedto the space frame at the radial distance of 490 cm from the interaction point Thepseudo-rapidity acceptance is |η| lt 06 and an azimuthal coverage develops between 1and 59 corresponding to 5 of the central barrel acceptance The HMPID allows oneto extend the particle identification for π and K up to pT asymp 3 GeVc and pT asymp 5 GeVcfor protons

PHOton Spectrometer (PHOS)

The PHOton Spectrometer (PHOS) is a high resolution electromagnetic spectrometercovering the pseudo-rapidity range |η| lt 013 and the azimuth between 220 to 320 andinstalled at the radial distance of 460 cm The detector technology is based on lead-tungstate (PbWO4) crystals The PHOS is used to detect photons in the transversemomentum range between 05 to 10 GeVc including diphotons coming from the decayof the light pseudoscalar neutral mesons

36 Chapter 2 ALICE at the CERN LHC

ElectroMagnetic Calorimeter (EmCal)

The ElectroMagnetic Calorimeter (EMCal) and its extension the Di-jet Calorimeter(DCal) are sampling electromagnetic calorimeters with the pseudo-rapidity coverage|η| lt 07 and azimuth coverage from 80 to 187 (for the EMCal) and 260 to 327 (for theDCal) Specific allowance is made in the DCal acceptance for the space occupied by thePHOS detector The combined information of the EmCal and the DCal allows to studyjets and di-jets providing trigger signals for hard jets photons and electrons

222 The Forward DetectorsIn this section the ALICE sub-detectors covering the forwardbackward acceptance regionare presented These detectors are used to measure global observables especially thecentralityactivity of the collisions and the event plane

Forward Multiplicity Detector (FMD)

The Forward Multiplicity Detector (FMD) is based on the silicon strip technology Itis divided in seven disks perpendicular to the beam pipe located at distances between42 and 225 cm from the interaction point The goal of this sub-detector is to study thecharged particle multiplicity in the pseudo-rapidity ranges minus34 lt η lt minus17 and17 lt η lt 51 complementary to the one of the ITS

T0

The T0 is composed of two arrays of Cherenkov counters circularly arranged around thebeam pipe with a time resolution better than 50 ps The forward and backward parts ofthis sub-detector are located at 375 cm and minus727 cm covering a pseudo-rapidity rangeof 461 lt η lt 492 and minus328 lt η lt minus297 respectively It participates to thetrigger decision and to the estimation of the luminosity

V0

The V0 is composed of two scintillator disks installed around the beam axis on each sideof the interaction point The V0-A (for A-side corresponding to positive values of z) isinstalled at 329 cm from the interaction point it has a diameter of 100 cm and covers thepseudo-rapidity range 28 lt η lt 51 The V0-C (for C-side corresponding to negativevalues of z) is installed at minus90 cm from the interaction point it has a diameter of 74 cmand covers the pseudo-rapidity range minus37 lt η lt minus17

The V0 measures the charged particle multiplicity and by the measurement of thetime-of-flight difference between the A and C scintillators makes possible to identify andreject the beam-gas5 events This technique is illustrated in figure 24 beam-beam andbeam-gas events can be easily discriminated on the basis of the time correlation of thetwo signals reported on the x and y axes

5 A beam-gas event corresponds to an interaction between a beam ion and a nucleus of the residualgas in the beam pipe vacuum

22 A Large Ion Collider Experiment (ALICE) 37

Figure 24 Weighted average time-of-flight of the particles detected in V0-C versus V0-A Thedashed line intersection represents the time of the collisions at the interaction point or the crossingtime of the background tracks at the vertical plane z = 0 [60]

The V0 participates in the minimum-bias trigger decision and in the estimation of theluminosity Furthermore this sub-detector is involved in the centrality measurement inPb-Pb collisions

Photon Multiplicity Detector (PMD)

The Photon Multiplicity Detector (PMD) consists of two identical planes of detectorsmade of gas proportional counters with honeycomb structure and wire readout with Leadconverter in between located at 360 cm from the interaction point in opposite side ofmuon spectrometer The PMD covers the pseudo-rapidity region (23 lt η lt 37) Itmeasures the multiplicity and spatial distribution of photons and estimates the transverseelectromagnetic energy and the reaction plane event-by-event

ALICE Diffractive Detector (AD)

The ALICE Diffractive detector (AD) is a ALICE sub-detector which was installed dur-ing the Long Shutdown 2 (2013-2014) The goal of this sub-detector is to increase thepseudo-rapidity coverage (from 88 to 132 units) and to enhance trigger efficiency forlight particles produced in diffractive events This sub-detector also participates in theestimation of the multiplicity event-by-event It is composed of two double layers of scin-tillator counters one on each side of ALICE sensitive to charged particles with pT downto 20 MeVc In the A-side AD is installed at z = 170 m and covers the pseudo-rapidityrange 49 lt η lt 63 In the C-side the sub-detector is installed at z = minus195 m andcovers the pseudo-rapidity range minus70 lt η lt minus48

38 Chapter 2 ALICE at the CERN LHC

Zero Degree Calorimeter (ZDC)

The Zero Degree Calorimeter (ZDC) is composed of two identical sets of quartz spaghetticalorimeters located on both sides of the ALICE detector in fully horizontal position1125 m from the interaction point Each set of detectors consists of a neutron anda proton calorimeter Each of the neutron calorimeters has dimensions 7x7x100 cm3

while the proton calorimeters have dimensions 228x12x150 cm3 The ZDC detector iscompleted by two small electromagnetic calorimeter (ZEM) placed at 735 m from theinteraction point on one side detecting the energy of particles emitted in the pseudo-rapidity range 48 lt η lt 57 The ZDC is used to estimate the centrality in Lead-Leadcollisions

223 The Muon Spectrometer

Figure 25 The ALICE muon spectrometer layout [61]

The ALICE muon spectrometer (represented in figure 25) is 17 m long Thepseudo-rapidity coverage is minus40 lt η lt minus25 corresponding to the angular range171 lt θ lt 178 The muon spectrometer was designed to study quarkonia (Jψand Υ families) and light vector meson production (η ρω and φ) through their dimuondecays and open charm and beauty production (B and D hadrons) in the single-muonchannel The spectrometer is composed of several elements described in the followingsections

a Front Absorber

The first element of the ALICE muon spectrometer starting from the interaction pointis the front absorber (or hadron absorber) The hadron absorber suppresses all particlesexcept muons coming from the interaction vertex (mainly πplusmn and Kplusmn) It is made of

22 A Large Ion Collider Experiment (ALICE) 39

carbon and concrete (cf figure 26) in order to limit the multiple scattering and theenergy loss of the muons The inner beam shield protects the tracking chambers frombackground originating from particles at small angles It is made of tungsten lead andstainless steel to minimize the background arising from primary particles emitted in thecollision and from their showers produced in the beam pipe and in the shield itself

Figure 26 The ALICE front absorber structure [62]

The absorber is located 90 cm away from the interaction point just after the V0-Cand is 413 cm long

b Dipole Magnet

The dipole magnet provides a maximum magnetic field of 07 T and an integral fieldof 3 T middot m It is a warm magnet (one of the largest warm dipoles in the world) andit is cooled with a demineralized water-cooling system ensuring operating temperaturesbetween 15 to 25 C Its dimensions are 5 m in length 71 m in width and 9 m in heightThe dipole is centered at 994 m from the interaction point and the free gap betweenpoles has a diameter of approximately 3 m The dipole is designed to provide a horizontalmagnetic field perpendicular to the beam axis and its polarity can be reverted Themagnetic field is defined by requirements on the mass resolution for the heavy Υ states

c Tracking Chambers

The tracking system of the muon spectrometer is composed of five stations each sta-tion made of two chambers The distance between two chambers of a same station isbetween 10 and 20 cm The chambers are based on a Multiwire Proportional Cham-ber (MWPC) technology with pad-segmented cathodes [63] The tracking system wasdesigned to achieve the spatial resolution of 100 microm in the bending plane needed for ob-taining an invariant mass resolution of sim 100 MeVc2 at the Υ mass The segmentationof the cathodes allows the spectrometer to operate with maximum hit densities of about5 middot 10minus2 cmminus2 sufficiently large to cope with the observed multiplicity in central Pb-Pbcollisions

40 Chapter 2 ALICE at the CERN LHC

d Iron Wall

The iron wall complements the hadron absorber It is 12 m thick and covers a transversesurface of 56times 56 m2 It is located 15 m away from the interaction point before thetrigger chambers The goal of this element is to suppress all hadrons emerging from thefront absorber The combined action of the iron wall and the front absorber imposesthe muons to have a minimum momentum of sim 4 GeVc in order to reach the triggerchambers

e Trigger Chambers

The ALICE muon spectrometer is equipped with two trigger stations allowing events ofinterest for the muon physics to be selected Each station is composed of two chambersbased on the Resistive Plate Chamber (RPC) technology ensuring the time resolution of2 ns necessary for the identification of the bunch crossing The first station is located at16 m just after the iron wall and the second station at 17 m

Several trigger conditions are hard-coded in the trigger electronics The electronicsprovides the possibility to use two pT thresholds used for different physics and the list oftriggers is

bull MSL at least one muon with pT larger than the low-pT threshold

bull MSH at least one muon with pT larger than the high-pT threshold

bull MLL at least two muons of same charge with pT larger than the low-pT threshold

bull MUL at least two muons of opposite charge with pT larger than the low-pT thresh-old

In addition to these trigger conditions the A-pT trigger condition can also be defined itis the minimum-pT trigger threshold for which a muon is firing the trigger and the valueof this trigger is 05 GeVc

In LHC Run 2 the single-muon high-pT threshold was set to 42 GeVc while thevalue of the single-muon low-pT threshold depended on the data taking periods In thepp data taking during Run 2 two different values have been considered for the single-muonlow-pT threshold 1 GeVc allowing one to access φ meson pT down to sim 15 GeVc and05 GeVc allowing one to access φ meson pT down to almost 0 GeVc

224 The ALICE software frameworkThe ALICE software (AliRoot [64] and AliPhysics [65]) is based on ROOT [66] a soft-ware originally designed at CERN for particle physics data analysis ROOT AliRoot andAliPhysics are written in C++ and are used to handle the online-offline data The soft-ware also manages the Monte-Carlo simulation framework by interfacing several MCgenerators (PYTHIA [67] HIJING [68]) and particle transport codes which simulate thedetector response (GEANT3 [69] GEANT4 [70] and FLUKA [71])

The working flow of the ALICE software is represented in figure 27 where the mainstructures of the online-offline handling are shown The reconstruction steps are the

22 A Large Ion Collider Experiment (ALICE) 41

same for the raw data and MC data At the end of the reconstruction chain the dataare available in the AOD format (Analysis Object Data) From the AOD data furtherdata formats can be derived designed for any specific analysis In the case of the analysisperformed in this thesis the AOD events are reduced to the AliLMREvent format containingthe information of interest for the study of light-neutral meson production decaying intomuons

Simulation Reconstruction

Mon

teCarlo

RealData

Particles

HitsSDigitsSDigits Digits

Clusters

Vertex

Tracks ESD AOD

Trigger

Detector

HLT

DAQ Raw Data

Online Offline

Figure 27 Schema of the reconstruction chain for data and simulation

225 The ALICE UpgradeDuring LHC Run 1 and Run 2 the goal of ALICE is to explore the unprecedented energyregime available in heavy ion collisions see section 124 In the LHC Run 3 and Run 4ALICE we move from the exploration phase to a precision-measurement phase For thisreason ALICE is undertaking a complex upgrade program of its detectors with theinstallation of the upgraded sub-detectors to take place in 2019ndash2020 during the LHCLong Shutdown 2

Physics Motivations

The ALICE upgrade will preserve the specificities of the ALICE physics program withrespect to the other LHC experiments The track reconstruction performance will beimproved in terms of spatial precision and efficiency in particular for low-momentumparticles in order to select more efficiently the decay vertices of heavy-flavor mesons andbaryons The particle identification capabilities of the apparatus will be consolidatedthey represent a crucial tool for the selection of heavy-flavor quarkonium and dileptonsignals at low momentum In the following the main items of the foreseen physics programare shortly reviewed

42 Chapter 2 ALICE at the CERN LHC

bull Heavy Flavors characterization of the parton energy loss study of the transportof heavy quarks in the medium and the hadronization of heavy flavors In ALICE thefocus is placed on the low-momentum region down to zero pT and the reconstructionof heavy-flavor hadrons (mesons and baryons) and the possibility to measure theflavor-dependence in low-momentum jets using light flavor strange and charmedhadrons reconstructed within jets

bull Quarkonia study of the quarkonia dissociation (and possible regeneration) asprobe of the deconfined nature and temperature of the medium In ALICE theemphasis is in the low-momenta region and the possibility to study Jψ ψ(2S) andΥ in central and forward rapidity At forward rapidity in particular the MuonForward Tracker (MFT) will allow the prompt Jψ component to be statisticallyseparated from the displaced production and the ψ(2S) to be observed even inthe most central PbndashPb collisions thanks to a strong reduction of the non-promptbackground

bull Low-Mass Dileptons and Thermal Photons estimation of the initial temper-ature of the medium and investigation of the chiral nature of the phase transitionALICE will access this physics both in the dielectron and dimuon channels down tozero pT

bull Beyond Standard Model specific studies are also undergoing to assess the sen-sitivity of ALICE to the measurement of possible low-mass dark matter bosonsdecaying into electron or muon pairs thanks to the improvement of the discrimina-tion between prompt and non-prompt dileptons

Inner Tracking System (ITS)

The current ALICE Inner Tracking System (ITS) will be totally dismounted at the endof the LHC Run 2 to be replaced by a new detector during Long Shutdown 2 The newITS [72] will be composed of seven cylindrical layers of Monolithic Active Pixel Sensors(MAPS) the innermost one having an internal radius of 224 mm limited by the externalradius of the future beam pipe The internal radius of the outermost layer is 3918 mm

The hit resolution of the detector will be of about 5 microm and the material budget ofthe three innermost layers will be reduced from the present 11 to 03 of the radiationlength per layer these features provide an improvement by a factor about three for thetrack impact parameter resolution in the transverse plane The new ITS would have apseudo-rapidity coverage of |η| lt 122 This upgrade will improve the precision in thesecondary vertex separation (from beauty charm and strange particle decays)

Muon Forward Tracker

The Muon Forward Tracker (MFT) [73] will be a new sub-detector of ALICE made of fivedisks of the same MAPS used in the upgraded ITS The MFT will provide precise track-ing and secondary vertex reconstruction for muon tracks in the pseudo-rapidity regionminus36 lt η lt minus25 within the acceptance of the muon spectrometer

22 A Large Ion Collider Experiment (ALICE) 43

Figure 28 Simulation of low-mass dimuons with and without ALICE upgrade

The measurement of prompt dimuon sources in the low-mass region will strongly ben-efit from the addition of the MFT to the muon spectrometer A significant improvementup to a factor of about 4 is expected for the mass resolution of the narrow resonancesη ω and φ for which resolutions of sim 15 MeVc2 are expected (to be compared withthe current sim 50 MeVc2 resolution at the mass of the φ meson see figure 28) thiswill translate into a significant improvement of the measurements involving these parti-cles allowing at the same time a reliable identification of the underlying thermal dimuoncontinuum and the measurement of the in-medium modified line shape of the short-livedρ meson A precision of about 20 is expected for the observation of these sourcescurrently not feasible due to the very small signal-over-background ratio affecting themeasurement with the present muon spectrometer

TPC

The expected increase of the LHC luminosity after LS2 corresponding to an interactionrate about 50 kHz in PbndashPb implies that TPC operation with a gating grid is no longerpossible This motivates the choice of GEMs for the new readout chambers since theyfeature intrinsic ion blocking capabilities that avoid massive charge accumulation in thedrift volume from back-drifting ions and prevent excessive space-charge distortions Thepresent particle identification (PID) capability via the measurement of the specific ioniza-tion dEdx and the combined momentum resolution of the central barrel tracking systemmust be retained by the TPC upgrade [74] preserving the excellent performance of thecurrent detector

Fast Interaction Trigger (FIT)

The Fast Interaction Trigger (FIT) [75] will be a new sub-detector of ALICE expectedto match and even exceed the functionality and performance (fast event triggering min-imum bias luminosity and charged-particle multiplicity measurements) currently secured

44 Chapter 2 ALICE at the CERN LHC

by three ALICE sub-detectors the T0 the V0 and the FMD detectors The location ofFIT will be similar to that of the current V0 and T0 modules with sensors on both sidesof the Interaction Point (IP) The restrictions imposed by the desired functionality tightspace requirements and the need to minimize the material in the vicinity of the inter-action point have narrowed the choice of detector technologies for FIT to either plasticscintillator- andor Cherenkov radiator

ALICE O2 (ALICE Online-Offline)

After the LHC LS2 the Pb-Pb collision interaction rate will be approximately 50 kHzSince the ALICE physics program will focus on untriggerable signals a continuous read-out will be required in order for all events to be recorded The resulting data throughputfrom the detector has been estimated to be larger than 1 TBs for PbminusPb events roughlytwo orders of magnitude more than in Run 1 and Run 2 To minimize the costs and therequirements of the computing system needed for data processing and storage ALICE isdeveloping a new Computing Framework for Runs 3 and 4 called ALICE Online-Offline(ALICE O2) [76] This framework is designed for a maximal reduction of the data volumeread out from the detector as early as possible during the data-flow

Chapter 3

Data Sample Selection andIntegrated Luminosity Evaluation

Summary31 Data Sample Event and Track Selection 45

32 Integrated Luminosity Evaluation 46

321 F inorm Calculation 47

322 The MB Trigger Cross Section 50

323 Lint Evaluation 51

31 Data Sample Event and Track SelectionThe analysis presented in this thesis is based on a data sample collected by ALICE in2016 in pp collisions at

radics = 13 TeV amounting to asymp 26 times 108 events recorded with

a dimuon trigger This is the largest data sample recorded with the low-pT threshold atsim 05 GeVc as of today (September 2017)

The ALICE data taking is organized into two levels at the first level data are orga-nized into periods each one characterized by the same detector and beam configurationsat the second level data within a given period are further organized into runs each onespanning the interval of two consecutive stops in the data acquisition1 Runs retained forthe analysis are selected on the basis of the quality assurance conditions defined for themuon spectrometer These conditions imply the good operation of all detectors involvedin the analysis of the muon data (muon tracking chambers muon trigger chambers SPDlayers of the ITS V0 and T0) The full list of runs used for the present analysis is reportedin appendix A

The Minimum-Bias (MB) trigger condition for the considered data sample is givenby the logical AND of the signals given by the two V0 detectors (V0AND) [48] Eventscontaining a muon pair are selected by means of a specific dimuon trigger based on thedetection of two muon candidate tracks in the trigger system of the muon spectrometerin coincidence with the MB condition Due to the intrinsic momentum cut imposed bythe detector only muons with pTmicro amp 05 GeVc manage to leave a signal in the triggerchambers Both unlike-sign and like-sign dimuon triggers were collected the like-sign

1 The data acquisition can be stopped either because of beam-related or detector-related issues

46 Chapter 3 Data Sample Selection and Integrated Luminosity Evaluation

trigger sample was downscaled by a factor that varied from run to run according to theinstantaneous luminosity

Background events not coming from beam-beam interactions are rejected by perform-ing an offline selection based on the timing information from the V0 detectors Moreoverit is requested that at least one SPD tracklet contributes to the vertex reconstructed bythe ITS

Track reconstruction in the muon spectrometer is based on a Kalman filter algo-rithm [43 77 78] Muon identification is performed by requiring the candidate track tomatch a track segment in the trigger chambers (trigger tracklet) This request selectsmuons with pTmicro amp 05 GeVc and as a consequence significantly affects the collectedstatistics for dimuons with invariant mass 1 GeVc2 and pT 1 GeVc A harder pro-grammable pT threshold can be imposed on single muons when defining the trigger condi-tions according to the specific physics target it was not the case for the data consideredin the present analysis for which the trigger condition was based on any trigger-matchedmuon Due to the geometrical acceptance of the muon spectrometer the pseudo-rapidityselection minus400 lt ηmicro lt minus250 on the muon tracks is imposed where ηmicro is defined in thelaboratory frame in order to remove the tracks close to the acceptance borders of thespectrometer where the acceptance drops abruptly Muon pairs are built combining twomuon tracks that satisfy the cuts mentioned above

The invariant mass spectrum was obtained both for Opposite-Sign (OS) and Like-Sign (LS) muon pairs the latter being considered for background subtraction relatedpurpose It should be noted that the OS component coming from the LS triggers wassafely neglected in the analysis so that only LS pairs were extracted from the LS-triggeredevents they were upscaled run by run by the inverse of the downscaling factor appliedin the data taking

32 Integrated Luminosity EvaluationThe integrated luminosity for the considered data sample was evaluated as Lint =NMBσMB where NMB is the equivalent number of MB events for the analyzed eventsample and σMB the MB trigger cross section The value of NMB was obtained by usingthe following formula

NMB =sumi=run

F inorm timesN i

MUL (31)

where the N iMUL is the number of events fulfilling the unlike-sign dimuon trigger condi-

tion (MUL given by the presence of at least two tracklets in the muon trigger systemof opposite sign both satisfying the single-muon pT-trigger condition) and F i

norm is thenormalization factor to convert the number of MUL events in the analyzed sample to theequivalent number of MB events In the present analysis two conditions are consideredto estimate the number of MB events

bull The first condition (in the following referred to as ldquoV0rdquo) is theCINT7-B-NOPF-MUFAST one This condition is defined by the coincidence oftwo signals in the V0-A and -C sub-detectors with the requirement that the

32 Integrated Luminosity Evaluation 47

coincidence actually comes from a valid beam-beam interaction (B-NOPF) It is alsorequired that the detectors implied in the definition of the MUL trigger conditionare also included in the readout for the considered M B events this is guaranteedby the composition of the specific MUFAST trigger cluster containing the SPDMUON_TRK MUON_TRG T0 V0 and AD detectors

bull The second condition (in the following referred to as ldquoT0rdquo) is based on the coinci-dence of the above condition CINT7-B-NOPF-MUFAST and the level-0 trigger condition0TVX defined by the coincidence of two signals in the T0-A and -C sub-detectors

321 F inorm Calculation

Three methods are usually considered to compute the Fnorm factor run by run one basedon the counting scaler information (online method) and two based on the reconstructeddata (offline methods)

Pile-Up correction

Regardless of the method one needs to estimate the pile-up contribution in order toproperly correct the estimation of NMB The pile-up correction factor (PU) is defined fora given run i as

PU i = microi

1minus eminusmicroi

microi = minus ln1minus FMBi

purity times L0biMB

Di timesN icolliding times fLHC

where

bull fLHC is the frequency of one bunch in the LHC (11245 Hz)

bull N icolliding is the number of colliding bunches

bull Di is the run duration as given by the Central Trigger Processor (CTP)

bull L0biMB is the scaler input of the level-0 trigger for the considered MB condition

bull FMBipurity is the purity factor associated to the considered MB condition

The purity factor for a generic trigger condition X is computed offline as the fractionof physics-selected (PS) X-trigged events [79] divided by the total number of X-triggedevents

FXipurity = N i

X(PS)N iX(ALL) (32)

In the case of the ldquoT0rdquo MB condition the purity factor is considered equal to 1Figure 31 shows the evolution of the purity factor for all the periods involved in thisanalysis and for the MUL and the ldquoV0rdquo MB trigger conditions

Figure 32 shows the evolution of the pile-up correction factor for the periods involvedin this analysis and for the two conditions considered for the estimate of the number ofMB events

48 Chapter 3 Data Sample Selection and Integrated Luminosity Evaluation

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

0

02

04

06

08

1

Purity factor for MUL

Purity factor for V0 MB condition

B TeyssierWork Thesis

Figure 31 Purity factor for the periods f to p in chronological order

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Pile

-Up

corr

ectio

n fa

ctor

1

105

11

115T0 evaluation

V0 evaluation

B TeyssierWork Thesis

Figure 32 Pile-Up correction for the periods f to p in chronological order

Fnorm Evaluation with Online Method

The online method for the evaluation of the Fnorm factor is based on the information ofthe L0b scaler inputs for the MUL and MB triggers conditions In this case F i

norm iscomputed for a given run i as

F inorm = PU i times FMBi

purity times L0biMB

FMULipurity times L0biMUL

(33)

where FXipurity is the purity factor associated to the events selected by the trigger condition

X This method does exploit the full event sample in the analyzed data The run-by-run

32 Integrated Luminosity Evaluation 49

evolution of the F inorm factor evaluated with this method is given in figure 33 both for

the ldquoV0rdquo and ldquoT0rdquo MB conditions

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Nor

mF

0

2

4

6

310times

method Online V0NormF

method Online T0NormF

B TeyssierWork Thesis

Figure 33 Normalization factor for the periods f to p in chronological order evaluated with theonline method both for the ldquoV0rdquo and ldquoT0rdquo MB conditions

Offline Methods

The offline methods are based on the comparison between the number of minimum biasevents in a given data sample and the number of minimum bias events in the same datasample satisfying at the same time the trigger condition of the analyzed events at thelevel-0 For the first offline method the following formula is used for a given run i

F inorm = PU i times MBi

(MBamp0MUL)i (34)

where

bull MBi is the number of physics-selected MB events

bull (MBamp0MUL)i is the number of physics-selected MB events also fulfilling the MULtrigger condition at the level-0

The run-by-run evolution of the F inorm factor evaluated with this method is given in

figure 34 both for the ldquoV0rdquo and ldquoT0rdquo MB conditionsThe second offline method is based on the formula

F inorm = PU i times MBi

(MBamp0MSL)i timesMSLi

(MSLamp0MUL)i (35)

where

50 Chapter 3 Data Sample Selection and Integrated Luminosity Evaluation

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Nor

mF

0

2

4

6

8

10

12310times

method Offline 1 V0NormF

method Oflline 1 T0NormF

B TeyssierWork Thesis

Figure 34 Normalization factor for the periods f to p in chronological order evaluated with the firstoffline method both for the ldquoV0rdquo and ldquoT0rdquo MB conditions

bull MSLi is the number of physics-selected events satisfying the single-muon triggercondition (MSL given by the presence of at least one tracklet in the muon triggersystem passing the all-pT single-muon threshold) in coincidence with the ldquoV0rdquo MBcondition

bull (MSLamp0MUL)i is the number of physics-selected MSL events (see above) also satis-fying the MUL trigger condition at the level-0

bull (MBamp0MSL)i is the number of physics-selected MB events also satisfying the MSLtrigger condition at the level-0

The run-by-run evolution of the F inorm factor evaluated with this method is given in

figure 35 both for the ldquoV0rdquo and ldquoT0rdquo MB conditionsThe relative rate of the MSL trigger condition relative to the MB and the MUL ones is

larger than the relative rate of the MUL trigger condition to the MB one this guaranteesthis second offline method to profit from a larger event sample resulting in a smallerstatistical uncertainty As expected the results from the two offline methods agree withinthe error bars

322 The MB Trigger Cross SectionThe ldquoMBrdquo cross section σMB was measured with a van der Meer scan for both theldquoV0rdquo and ldquoT0rdquo MB condition and found to be 578plusmn 12 mb for the ldquoV0rdquo conditionand 301plusmn 06 mb for the ldquoT0rdquo condition [80] As reported in [80] ldquowhen the LHC isoperated with isolated-bunch-based filling schemes the two detectors provide indepen-dent measurements of the luminosity with a total uncertainty of 23 When the LHC isoperated with bunch trains the V0-based luminosity is affected by non-trivial systematiceffects in this case the total uncertainty on the luminosity measured with T0 is 34rdquo

32 Integrated Luminosity Evaluation 51

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Nor

mF

0

2

4

6

8

10

12310times

method Offline 2 V0NormF

method Offline 2 T0NormF

B TeyssierWork Thesis

Figure 35 Normalization factor for the periods f to p in chronological order evaluated with thesecond offline method both for the ldquoV0rdquo and ldquoT0rdquo MB conditions

It should be noted that these values refer to the pp data taking of 2015 since thecorresponding results from the van der Meer scan of 2016 (when the data considered inthe present analysis were taken) is not available yet We thus currently assume a 5additional systematic uncertainty on σMB accounting for any possible difference betweenthe efficiency of the detectors involved in the MB trigger conditions between 2015 and2016

323 Lint EvaluationTo obtain the value of Lint for the data taking periods considered in this present analysisone has to assume a reference MB condition and a reference method for the evaluationof Fnorm From equation (31) one can expect that for a given MB condition the valuesof Fnorm coming from the online and offline methods discussed above agree between eachother to give the same estimation of NMB Moreover the definition of the integratedluminosity Lint = NMBσMB implies that the ratio between the NMB(V0) and NMB(T0)and then the ratio between Fnorm(V0) and Fnorm(T0) should be consistent with the ratiobetween σMB(V0) and σMB(T0) As one can see by comparing figures 33 to 35 thethree evaluation methods give compatible estimations for Fnorm However the expectedratio between the ldquoV0rdquo and ldquoT0rdquo estimations of Fnorm is only observed with the onlinemethod For this reason the online method (which also profits from the smaller statisticaluncertainties) is retained for the evaluation of the Lint value to be used for the presentanalysis

The resulting values of Lint are 844plusmn 000(stat)plusmn 042(syst) pbminus1 and904plusmn 000(stat)plusmn 452(syst) pbminus1 respectively when the ldquoT0rdquo and ldquoV0rdquo MBconditions are considered The ldquoT0rdquo MB condition assuring the most stable referenceis finally retained and considered in the present analysis

Chapter 4

Monte Carlo Simulations

Summary41 Light-Meson Decays 53

411 Kinematical Distributions 54412 Dalitz Decays 54413 Two-Body Decays 57

42 Dimuons from Open Heavy-Flavor Decays 60421 PYTHIAndash FONLL Comparison 61422 Decay Chain Length in the Open Heavy-Flavor Processes 62

This thesis work is devoted to the study of light-meson production decaying in two-muon (dimuon) channel The dimuon mass range of interest for this study goes fromthe production threshold (Mmicromicro = 2mmicro) to 15 GeVc2 and is named Low-Mass Region(LMR) This region gives access to the dimuon decays of the light vector (ρ ω and φ)and pseudo-scalar (η and ηprime) mesons discussed in section 41 In addition to these decaysa correlated dimuon continuum is also present in the LMR this contribution is treated insection 42 in terms of open charm and beauty processes

For each process discussed in the following the underlying physics is reviewed andthe main details of the corresponding MC simulations are given All the MC simulationsperformed in this thesis used GEANT3 as transport code

41 Light-Meson DecaysThe properties of the light mesons contributing to the LMR through their dimuon de-cays are reported in table 41 These mesons contribute to the LMR with two types ofdecays the two-body decays and the three-body (Dalitz) decays which will be discussedseparately in the following section All the light-meson decays involved in the LMR aresimulated with the AliGenMUONLMR parametric generator

As can be seen from the quark composition reported in table 41 the ρ and ω mesonscan be used as reference for particle production in the (ud) quark sector while strangenessproduction can be accessed via φ meson (and to a lesser extent η and ηprime mesons)measurement The physical width of the ρ meson significantly larger than one of theother particles contributing to the LMR corresponds to the life time of sim 13 fmc thismakes the ρ an ideal probe of in-medium modifications in the case of QGP productiongiven that a large fraction of the observed ρ mesons would decay inside the hot medium

54 Chapter 4 Monte Carlo Simulations

Particle Pole Mass [MeVc2] Width [MeVc2] Quark Compositionη 547862plusmn 0018 (131plusmn 005) middot 10minus3 1radic

6

(uu + ddminus 2ss

)ρ 77526plusmn 025 1491plusmn 08 1

2

(uuminus dd

)ω 78265plusmn 012 849plusmn 008 1

2

(uu + dd

)ηprime 95778plusmn 006 0198plusmn 0009 1radic

3

(uu + dd + ss

)φ 1019461plusmn 0019 4266plusmn 0031 ss

Table 41 Property of light-mesons involved in the dimuon mass spectrum values taken from [4]

411 Kinematical DistributionsThe kinematics parametrization of the light mesons in the AliGenMUONLMR generator areprovided by a pT-y distribution estimated by PHOJET [81 82] (based on a Dual PartonModel combined with perturbative QCD)

412 Dalitz DecaysAmong the light mesons reported in table 41 the η ω and ηprime mesons give a sizableDalitz decay contribution to the LMR The involved decay channels are summarized intable 42

Process Branching Ratio (BR)ηrarr micro+microminusγ (31plusmn 04) middot 10minus4

ωrarr micro+microminusπ0 (13plusmn 06) middot 10minus4

ηprime rarr micro+microminusγ (108plusmn 027) middot 10minus4

Table 42 Dalitz decay processes in the LMR and the branching ratios used in the analysis

The Feynman diagram corresponding to the Dalitz decay under discussion are shownin figure 41 In the considered processes the parent mesons decay electromagnetically intoone virtual photon with mass M and a third body (real photon or π0) with the virtualphoton converting into a muon pair

η

γlowast

microminus

micro+

γ

1(a) ηrarr micro+microminusγ

ω

γlowast

microminus

micro+

π0

1(b) ωrarr micro+microminusπ0

ηprime

γlowast

microminus

micro+

γ

1(c) ηprime rarr micro+microminusγ

Figure 41 Feynman diagrams of the Dalitz decays of interest for the dimuon LMR

The ALICE muon spectrometer is not equipped for detecting neither the real photonnor the π0 emitted within the Dalitz decays discussed here these decays are identified by

41 Light-Meson Decays 55

]2c [GeV-micro+microM0 01 02 03 04 05 06 07 08

- micro+ micro

MdN

d

0

5

10

15

20

610times (gen)γ-micro+micro rarr η

(a) η

]2c [GeV-micro+microM0 02 04 06 08 1

- micro+ micro

MdN

d

0

2

4

6

610times (gen)0π-micro+micro rarr ω

(b) ω

]2c [GeV-micro+microM0 02 04 06 08 1 12

- micro+ micro

MdN

d

0

1

2

3

4

5610times (gen)γ-micro+micro rarr η

(c) ηprime

Figure 42 Generated dimuon mass distribution of Dalitz decay integrated in full phase space

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

γmicromicrorarrη for -micro+micro)ε times(A

(a) η

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

0πmicromicrorarrω for -micro+micro)ε times(A

(b) ω

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

γmicromicrorarrη for -micro+micro)ε times(A

(c) ηprime

Figure 43 Acceptance times efficiency of Dalitz decay

]2c [GeV-micro+microM0 01 02 03 04 05 06 07 08

- micro+ micro

MdN

d

0

005

01

015

02

610times (rec)γ-micro+micro rarr η

(a) η

]2c [GeV-micro+microM0 02 04 06 08 1

- micro+ micro

MdN

d

0

20

40

60

80

100

310times (rec)0π-micro+micro rarr ω

(b) ω

]2c [GeV-micro+microM0 02 04 06 08 1 12

- micro+ micro

MdN

d

0

20

40

60

80

310times (rec)γ-micro+micro rarr η

(c) ηprime

Figure 44 Reconstructed dimuon mass distribution of Dalitz decay integrated in full phase space

56 Chapter 4 Monte Carlo Simulations

looking at the mass distribution of the dimuons coming from the virtual photon conversionFor this reason it is important to have a theoretical description of the shape of suchmass distributions they can be computed in pure QED under the hypothesis of a point-like electromagnetic transition vertex with the deviation from the real transition vertexquantified by a form factor |F (M2)|2 see Equations (41) to (43)

dΓ (ηrarr micromicroγ)dM = 2M 2

3α

π

Γ (ηrarr γγ)M2

(1minus M2

m2η

)3 (1 +

2m2micro

M2

)

timesradicradicradicradic(1minus 4m2

micro

M2

) ∣∣∣Fη (M2)∣∣∣2

(41)

dΓ (ωrarr micromicroπ0)dM = 2M α

3πΓ (ωrarr γπ0)

M2

(1 +

2m2micro

M2

)radicradicradicradic(1minus 4m2micro

M2

)

times(1 + M2

m2ω minusm2

π0

)2

minus 4m2ωM

2

(m2ω minusm2

π0)2

32 ∣∣∣Fω (M2)∣∣∣2

(42)

dΓ (ηprime rarr micromicroγ)dM = 2M 2

3α

π

Γ (ηprime rarr γγ)M2

(1minus M2

m2ηprime

)3 (1 +

2m2micro

M2

)

timesradicradicradicradic(1minus 4m2

micro

M2

) ∣∣∣Fηprime (M2)∣∣∣2

(43)

where the π0 η ω and ηprime pole masses are taken from the PDG tables [4] and the formfactors are expressed by the pole-parametrization for the η and ω mesons and from aBreit-Wigner form for the ηprime meson∣∣∣Fη (M2

)∣∣∣2 = 1(1minus M2

Λ2η

)2 (44)

∣∣∣Fω (M2)∣∣∣2 = 1(

1minus M2

Λ2ω

)2 (45)

∣∣∣Fηprime (M2)∣∣∣2 = m4

0

(m20 minusM2)2 +m2

0Γ20 (46)

For the η andω form factors the corresponding Λ parameter is taken from a recent analysison p-A NA60 data [83] while for the ηprime form factor the parameters m0 = 0764 GeVc2

and Γ0 = 0102 GeVc2 are extracted from a fit on the Lepton-G data [84] The invariantmass distributions Equations (41) to (43) are implemented in the description of theDalitz decays in the AliGenMUONLMR generator together with the definition of the formfactors Equations (44) to (46) This allows one to extract a properly distributed value ofthe virtual photon invariant mass to be used to simulate the decays ηrarr γlowastγ ωrarr γlowastγ

and ηprime rarr γlowastγ from here the full kinematics of the virtual photon can be extractedallowing in turn the kinematics of the muon pair to be evaluated

41 Light-Meson Decays 57

Figure 42 shows the generated dimuon mass distribution for the three Dalitz decaysof interest here The ηprime mass distribution (figure 42c) shows a characteristic enhancementcorresponding to the ρω peak given by the transition form factor which can be easilyinterpreted in terms of the Vector Meson Dominance model [84] For each decay the pTand y dependence of the product of geometrical acceptance and reconstruction efficiency(A times ε) is shown in figure 43 As expected the phase space coverage at low-pT is moreimportant for the Dalitz decays allowing for larger values of the dimuon invariant massFor the ηrarr micro+microminusγ decay which is the reference process for the extraction of the η-mesonsignal (Atimes ε)micro+microminus is negligible for pT

micromicro 05 GeVc putting a strong constraint in theavailable phase space for the η-meson measurement

Figure 44 shows the reconstructed dimuon mass distribution for each Dalitz decayintegrated over minus400 lt y lt minus250 and 00 lt pT lt 100 GeVc These shapes enter asingredients in the hadronic cocktail fit (discussed in section 52) imposing their profiles tobe sufficiently smooth for each phase space interval considered in the analysis since theseshapes extend over a large mass range and are not easily parameterizable a significantlylarge MC statistics is needed especially when (Atimes ε)micro+microminus is particularly low

413 Two-Body DecaysThe two-body decays of interest for the present thesis work are listed in table 43 withthe corresponding branching ratios For the ω rarr micro+microminus and φ rarr micro+microminus decays thebranching ratios are taken as the average (weighted by the corresponding uncertainty) ofthe available measurements of BR(micro+microminus) and BR(e+eminus) assuming lepton universality inorder to reduce the final uncertainty

Process Branching Ratio (BR)ηrarr micro+microminus (58plusmn 08) middot 10minus6

ρrarr micro+microminus (455plusmn 028) middot 10minus5

aωrarr micro+microminus (728plusmn 014) middot 10minus5

bφrarr micro+microminus (2954plusmn 0030)middot 10minus4

a The value reported in this table for the ω is the weighted average measurement of BR(ωrarr l+lminus)The BR(micro+microminus) is (90plusmn 31) middot 10minus5

b The value reported in this table for the φ is the weighted average measurement of BR(φ rarr l+lminus)The BR(micro+microminus) is (287plusmn 019) middot 10minus4

Table 43 Two-body decay processes in the LMR and the branching ratios used in the analysis

The decay of the vector mesons ρ ω and φ into two muons is mediated by a virtualphoton V rarr γlowast rarr micro+microminus (see figures 45b to 45d) The decay of the pseudo-scalar ηmeson into two muons is a 4th order electromagnetic process (see figure 45a) mediatedby two virtual photons where the micro+ coming from one γlowast and the microminus coming from theother γlowast are contracted

The two-body decays are implemented in the AliGenMUONLMR generator approximatingthe narrow mass line shapes of the η ω and φ mesons with a Dirac delta distributiondefined at the resonance pole mass since their physical widths are negligible with respect

58 Chapter 4 Monte Carlo Simulations

η

γlowast

microminus

γlowast

micro+

1(a) ηrarr micro+microminus

ργlowast

microminus

micro+

1(b) ρrarr micro+microminus

ωγlowast

microminus

micro+

1(c) ωrarr micro+microminus

φγlowast

microminus

micro+

1(d) φrarr micro+microminus

Figure 45 Feynman diagrams of two-body decays of the light neutral meson η ρ ω and φ

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

1

2

3

4

5

610times (gen)-micro+micro rarr ρ

Figure 46 Generated mass distribution for the ρrarr micro+microminus process see equation (47)

to the detector mass resolution On the contrary for the ρ meson due to its natural largemass distribution the following parametrization is used [8385]

dNdM =

α2m4ρ

3 (2π)4

radic1minus 4m2

micro

M2

(1 + 2m2

micro

M2

) (1minus 4m2

π

M2

)32

(m2ρ minusM2

)2+m2

ρΓ2ρ(M)

(2πMT )32 eminusMTρ (47)

with a mass-dependent width

Γρ(M) = Γ0ρmρ

M

M2

4 minusm2micro

m2ρ

4 minusm2micro

32

= Γ0ρmρ

M

(q

q0

)3

(48)

where the Γ0ρ is the full resonance width and mρ the resonance mass pole taken from [4]This distribution is shown in figure 46 one can appreciate the peculiar profile of this lineshape covering practically the whole LMR

For each decay the pT and y dependence of Atimes ε is shown in figure 47 As expectedthe phase space coverage at low-pT becomes larger as the mass of the meson increases

41 Light-Meson Decays 59

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrη for -micro+micro)ε times(A

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrρ for -micro+micro)ε times(A

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrω for -micro+micro)ε times(A

]c [GeVT

p0 2 4 6 8 10

y4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrφ for -micro+micro)ε times(A

Figure 47 Acceptance times efficiency of two body decay

(a) ηrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1

- micro+ micro

MdN

d

0

005

01

015610times (rec)-micro+micro rarr η

(b) ωrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

01

02

03

04

610times (rec)-micro+micro rarr ω

(c) ρrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

002

004

006

008

01

012

610times (rec)-micro+micro rarr ρ

(d) φrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

01

02

03

04

610times (rec)-micro+micro rarr φ

Figure 48 Reconstructed dimuon mass distribution of two body decays integrated in full phasespace

60 Chapter 4 Monte Carlo Simulations

For the ω rarr micro+microminus decay which is the reference process for the extraction of the ω-meson signal (Atimes ε)micro+microminus is significant down to pT = 00 GeVc in the rapidity rangeminus400 lt y lt minus325 and down to pT asymp 20 GeVc towards the y = minus250 limitFor the φ rarr micro+microminus decay from which φ-meson signal can be extracted (Atimes ε)micro+microminus issignificant down to pT = 00 GeVc in the rapidity range minus400 lt y lt minus300 and downto pT asymp 20 GeVc towards the y = minus250 limit

Figure 48 shows the reconstructed dimuon mass distribution for each two-body decayintegrated over minus400 lt y lt minus250 and 00 lt pT lt 100 GeVc These shapes enter to-gether with the Dalitz one discussed in the previous section as ingredients in the hadroniccocktail fit From the mass distributions in figure 48 the detector mass resolution for thenarrow η ω and φ mesons can be estimated performing a Gaussian fit on the centralpart of the peaks the value are found to be ση asymp 458 MeVc2 σω asymp 489 MeVc2 andσφ asymp 520 MeVc2

42 Dimuons from Open Heavy-Flavor DecaysIn the low mass region in addition to the Dalitz and two-body decays of light neutralmesons two other processes may contribute namely the so-called open charm and openbeauty processes In these processes a correlated muon pair comes from the simultaneoussemi-muonic decay of two correlated heavy-flavor hadrons coming from the hadronizationof a heavy qq pair These processes are illustrated in figure 49 for the open charm andbeauty

c

DX

micro

c

D

micro

X

b

BX

micro

b

B

micro

X

Figure 49 Illustration of open heavy-flavor decays

The open charm and beauty processes are generated with the PYTHIA6 MC gener-ator PYTHIA generates the primary cc (or bb) quark pairs performs the correspondinghadronization as well as the decay of the heavy flavor hadrons The decays of the long-livedparticles possibly appearing in the decay chains of the heavy-flavor hadrons are performedby the transport code GEANT3 To save CPU time the PYTHIA6-based parametric gener-ator (AliGenCorrHF) is used developed within the AliRoot framework generating oneheavy-flavor pair per event to further optimize the simulation the first heavy hadronpair is produced in the rapidity hemisphere of the muon spectrometer

The simulation of the open charm and beauty processes depends of the knowledgeof the kinematic distributions of the primary cc (or bb) quark pairs determining the

42 Dimuons from Open Heavy-Flavor Decays 61

kinematics of the first hadron pair and thus the shape of the mass distribution of finalmuon pairs The cc and bb kinematic distributions are known with large uncertainties atforward rapidity at the LHC energies due to the lack of measurements of heavy flavorhadrons in this kinematic range For this reason we also considered a second modelFONLL [86] (for Fixed-Order plus Next-to-Leading Log) giving an alternative descriptionof the cc and bb kinematic distributions based on some perturbative calculation madepossible by the large mass of the charm and beauty quarks To optimize the CPU timefor the simulations based on the FONLL predictions a reweighting is applied on the ex-isting simulations based on the ratio between the (pT minus y) parton distributions given byPYTHIA and FONLL The reweighting has been performed considering three FONLL kinemat-ics distributions the central prediction the prediction corresponding to the upper limitassociated to the uncertainty range and the prediction corresponding to the lower limitassociated to the uncertainty range in this way we can compare up to four hypothesesfor the input of the open charm and beauty processes

The discussion presented in the following section applies to the open charm processas well as to the open beauty one similarly each figure will include two panels the ldquoardquoone dedicated for the open charm case the ldquobrdquo for the beauty case

421 PYTHIAndash FONLL ComparisonTo estimate the difference between the available hypotheses on the input parton kinemat-ics the ratio of the FONLL partonic pT distributions (corresponding to the central valueand the upper-lower limits of the uncertainty range) to the PYTHIA one is shown in Fig-ure 410 In this figure the ratio corresponding to FONLL central value is represented insolid curve and the ratios corresponding to the upper and lower limits of FONLL uncertaintyrange are represented as an uncertainty band As can one see the ratio of the centralFONLL value to PYTHIA deviates significantly from unity the deviation becomes strongerwhen the upper-lower limits of the FONLL prediction are considered The PYTHIA-FONLLdisagreement is stronger for the charm than for the beauty

It is now interesting to investigate how the difference between the PYTHIA and FONLLpredictions for the input kinematic distributions of the cc and bb quark pairs affects theshape of the reconstructed dimuon mass spectra which will be used as ingredients ofthe fit of the data To do so the reconstructed mass spectra corresponding to the fouravailable MC inputs are compared in figure 411 PYTHIA FONLL central value FONLLupper value and FONLL lower value For the sake of comparison the four distributionsare normalized to the same integral In the case of the open charm process figure 411athe differences between the models are clearly visible accross the considered mass rangewhile for the open beauty process figure 411b there is a remarkable agreement betweenthe curves A possible way to quantify the uncertainty on reconstructed dimuon massdistributions of open charm and beauty due to the model assumed for the input partonicdistribution is to evaluate the FONLL over PYTHIA ratios as a function of the dimuon massas shown in figure 412

As expected the ratios for the open beauty process stay significantly closer to unitythan the open charm process By inspecting the graphs one can estimate the uncertaintyon the open charm shape to be of the order of 15 in the LMR significantly increasing

62 Chapter 4 Monte Carlo Simulations

]c [GeVT

p0 2 4 6 8 10

ratio

FO

NLL

Pyh

tia fr

om C

harm

0

1

2

3

(a) charm

]c [GeVT

p0 2 4 6 8 10

ratio

FO

NLL

Pyh

tia fr

om B

eaut

y

0

1

2

3

(b) beauty

Figure 410 Partonic pT distribution ratio FONLL [87] over PYTHIA the black curve represents thereference value of the ratio and the red hatching represents the error according to FONLL model

]2c [GeV-micro+microM0 1 2 3 4 5

au

0

10

20

30

40

50

3minus10times

FONLL

PYTHIA

FONLL - max

FONLL - min

(a) open charm

]2c [GeV-micro+microM0 1 2 3 4 5

au

0

10

20

30

40

3minus10timesFONLL

PYTHIA

FONLL - max

FONLL - min

(b) open beauty

Figure 411 Reconstructed dimuon mass coming from open heavy flavor semi-leptonic decays

towards large masses while from the open beauty shape the uncertainty in the LMR stayswithin 5 We will come back to these uncertainties in section 52 where the fit routineallowing the signal extraction will be discussed

422 Decay Chain Length in the Open Heavy-Flavor Processes

In the open heavy-flavor processes considered in this section the number of decay stepsbetween the initial parton and the final muon (noted decay chain afterwards) can bepotentially large resulting in a weakening of the kinematic correlation between the initialand the final states If the decay chains associated to the two final muons are sufficiently

42 Dimuons from Open Heavy-Flavor Decays 63

]2c [GeV-micro+microM0 1 2 3 4 5

0

02

04

06

08

1

12

14

FONLL over Pythia

FONLL - Min over Pythia

FONLL - Max over Pythia

(a) open charm

]2c [GeV-micro+microM0 1 2 3 4 5

09

095

1

105

FONLL over Pythia

FONLL - Min over Pythia

FONLL - Max over Pythia

(b) open beauty

Figure 412 Dimuon mass spectrum ratio from FONLL (reference min and max value) over PYTHIA

long the initial qq correlation could be substantially washed out in the final muon pairFor this reason it is interesting to study the distribution of the decay chain length (λmicro)in simulated open charm and beauty processes defined as the number of decay stepsbetween the initial parton and the final muon

-microlength 0 2 4 6 8 10

+ microle

ngth

0

2

4

6

8

10

1

10

210

310

410

510

(a) open charm

-microlength 0 2 4 6 8 10

+ microle

ngth

0

2

4

6

8

10

1

10

210

310

410

510

(b) open beauty

Figure 413 micro-chain for open heavy flavor at generated level

In figure 413 the correlation between the λmicro of the positive and negative muons isshown for the dimuons coming from the open charm and beauty simulations In thisfigure on can clearly see that λmicro can get as large as 10 As expected the average λmicrovalues are larger for the open beauty process than the open charm one due to the largerphase space available

Since the λmicro distributions extend over relatively large ranges one can wonder which isthe impact of having short or long muon decay chains on the shape of the dimuon invariant

64 Chapter 4 Monte Carlo Simulations

]2c [GeV-micro+microM0 1 2 3 4 5

au

4minus10

3minus10

2minus10

1minus10

4le plusmnmicroλ = 4 amp plusmnmicroλ 3le plusmnmicroλ = 3 amp plusmnmicroλ 2le plusmnmicroλ = 2 amp plusmnmicroλ 1le plusmnmicroλ = 1 amp plusmnmicroλ

(a) open charm

]2 [GeVc-micro+microM0 1 2 3 4 5

au

4minus10

3minus10

2minus10

1minus10

4le plusmnmicroλ = 4 amp plusmnmicroλ 3le plusmnmicroλ = 3 amp plusmnmicroλ 2le plusmnmicroλ = 2 amp plusmnmicroλ 1le plusmnmicroλ = 1 amp plusmnmicroλ

(b) open beauty

Figure 414 Generated dimuon mass coming from open heavy flavor semi-leptonic decays withparticular λmicro

mass distributions To do so in figure 414 the dimuon mass distributions are shown forfour particular λmicro+λmicrominus combinations As expected shorter decay chains correspond toharder mass distributions

We thus verified that the shape of the invariant mass profile of the open charm andbeauty dimuons depends of the length of the decay chains of the two muons This meansthat to properly reproduce the dimuon mass profile of the open charm and beauty com-ponents in the data we have to correctly reproduce the distribution of the decay lengthchains for the simulated dimuons Now this is not a problem as long as any dimuon froman open charm or beauty process is retained both in the data and in the MC Howeverthe data considered for the signal extraction are obtained by subtracting the combinato-rial background from the raw dimuon spectrum implying that we should retain in theMC the correlated dimuons only But the correlation of a muon pair coming from anopen charm or beauty process is progressively lost as the length of the decay chains of thetwo muons increases and it is extremely hard mdash in terms of analysis strategy and CPUtime mdash to estimate and take such an effect into account in the MC simulations Thisintroduces a source of uncertainty when describing the correlated continuum in the datawith the superposition of the open charm and beauty simulations

Chapter 5

Signal Extraction

Summary51 Combinatorial Background Evaluation and Subtraction 65

511 The Event Mixing Technique 66

512 Monte Carlo Validation of the Event Mixing Technique 67

513 The Combinatorial Background Estimation 68

52 Invariant Mass Fit Procedure 70

521 Specific Constraints on the Hadronic Cocktail Components 71

522 Correlated Continuum Treatment 72

523 A Few Examples of Hadronic Cocktail Fits 76

In this chapter the main source of background for the dimuon decay channel will bediscussed as well as the strategy considered for the extraction of the signals of interestFrom now on following a convention widely used within the ALICE muon communityrapidity values are given in the positive axis justified by the symmetry of the pp collisionsystem with respect to y = 0

51 Combinatorial Background Evaluation and Sub-traction

The present analysis is based on the study of the OS dimuon invariant mass spectrumDimuons are built by combining muon pairs coming from the same event (see section 31)Since dimuons coming from the light-neutral meson decays of interest for this work cannotbe disentangled from the other dimuon sources any pair of muons must be consideredwhen building the dimuon invariant mass spectrum This implies that a fraction of theconsidered dimuons actually comes from randomly paired uncorrelated muons this frac-tion of dimuons is conventionally named ldquocombinatorial backgroundrdquo The ratio betweenthe correlated and uncorrelated dimuon components varies significantly according to thecollision system the considered mass region and the apparatus performance In the low-mass region the ALICE muon spectrometer gives correlated over uncorrelated dimuonratios as large as few units (in pp collisions) and as low as few percents (in the mostcentral Pb-Pb collisions)

66 Chapter 5 Signal Extraction

511 The Event Mixing TechniqueThe combinatorial background for the OS dimuons has been evaluated using an eventmixing technique based on the reasonable assumption that the LS dimuon sample doesnot contain correlated muon pairs The mixing event technique implies the creation of asample of uncorrelated dimuon formed by pairing two muons coming from two differentevents In the following we will identify dimuons built from a same event with the labelldquodirrdquo and dimuons built from different events with the label ldquomixrdquo The event mixingtechnique is illustrated in figure 51

Event A

micro+A1

microminusA2

Event B

microminusB1

microminusB2

micro+B3

Opposite Signmicro+A1micro

minusB1

micro+A1micro

minusB2

microminusA2micro+B3

Like Sign ++micro+A1micro

+B3

Like Sign minusminusmicrominusA2micro

minusB1

microminusA2microminusB2

Figure 51 Illustration of mixing events with two events one with two muons and one with threemuons

The mixed OS dimuon sample is used in the event mixing technique to estimatethe OS combinatorial background in the direct OS dimuon sample for this reason onlyevents sharing same global properties are considered in the event mixing Among theseglobal properties one can cite the z-position of the primary vertex the charged-particlemultiplicity or in nucleus-nucleus collisions the orientation of the event plane In the ppcollisions considered in the present analysis the impact of classifying the events accordingto the z-position of the primary vertex and the charged-particle multiplicity was testedresulting in no difference with respect to the case in which the events are mixed regardlessof their global properties1

The shape of the invariant mass distribution expected for the OS uncorrelated dimuonsis taken for each kinematic range considered in the analysis directly from the outputdistribution Nmix

+minus (M) given by the event mixing technique The normalization is fixed tothe integral of the distribution 2R(M)

radicNdir

++(M) middotNdirminusminus(M) extracted from the data

Nmix+minus (M) minusrarr Nmix

+minus (M)

int2R(M)

radicNdir

++(M) middotNdirminusminus(M) dMint

Nmix+minus (M) dM

(51)

The integral of the 2R(M)radicNdir

++(M) middotNdirminusminus(M) distribution is indeed a good estimation

of the total number of the OS dimuons in the data as long as the LS dimuon samples1 This is valid as long as the analysis is integrated over the mentioned global properties in particular

the charged-particle multiplicity

51 Combinatorial Background Evaluation and Subtraction 67

Ndir++ and Ndir

minusminus do not contain any correlated muon pair The R factor accounts for thepossible differences between the acceptances of ++ minusminus and +minus muon pairs

R(M) = A+minus(M)2radicA++(M) middotAminusminus(M)

(52)

The R factor was estimated as

R(M) = Nmix+minus (M)

2radicNmix

++ (M) middotNmixminusminus (M)

(53)

where Nmix++ and Nmix

minusminus is the number of dimuons for the given sign combination theacceptances are evaluated with the mixing

512 Monte Carlo Validation of the Event Mixing TechniqueA Monte Carlo approach was considered to check the quality of the combinatorial back-ground estimation as follows Events containing two muons were simulated with thekinematics extracted randomly and independently for the two muons from some pT andy distributions taken from the data The azimuthal angle of each muon was randomlydrawn within flat distribution and the charges also randomly attributed In this waythe OS sample of the direct dimuons from this MC event sample could be assumed to bepurely combinatorial by construction We could thus check if the procedure describedabove was able to reproduce its mass shape and normalisation To do this we appliedto this same MC sample the event mixing technique to obtain the mass shape with thecorrect normalization

The ratio RMCdirmix between the true and estimated mass shapes of the combinatorial

OS dimuons was thus extracted for each kinematics interval considered in the analysisSeveral options are possible for the trigger class of the events considered in the eventmixing procedure The considered trigger classes are based on the ldquoV0rdquo trigger conditionsee section 31 to which a specific condition is added based on the response of the muontrigger

bull ldquoMULrdquo based on the presence of at least two tracklets in the muon trigger systemof opposite sign both passing the low-pT single-muon threshold

bull ldquoMLLrdquo based on the presence of at least two tracklets in the muon trigger systemof like sign both passing the low-pT single-muon threshold

bull ldquoMSLrdquo based on the presence of at least one tracklet in the muon trigger systempassing the low-pT single-muon threshold

bull ldquoMSL-onlyrdquo it is defined by this logical combination of trigger conditionsMSL ampMUL ampMLL so it is the condition which minimizes the impact of the dimuontrigger condition on the retained events

The trigger condition of the events considered for the event mixing technique waschosen as the one maximizing the flatness of RMC

dirmix Figures 52 and 53 show that the

68 Chapter 5 Signal Extraction

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeVmicromicroM

0 1 2 3 4 5 6

Dir

ect

Mix

ed

06

08

1

12

14

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

lt 40y25 lt

c lt 100 GeVT

p00 lt = 13 TeVsALICE pp

MUL

MLL

MSL

Figure 52 Comparison of background evalua-tion ratio direct over mixed for ldquoMULrdquo ldquoMLLrdquoand ldquoMSLrdquo conditions

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeVmicromicroM

0 05 1 15 2 25 3

Dir

ect

Mix

ed

09

095

1

105

11

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

MSL

MSL amp MUL amp MLL

Figure 53 Comparison of background evalu-ation ratio direct over mixed for ldquoMSLrdquo andldquoMSL-onlyrdquo conditions

best results are obtained considering events satisfying the ldquoMSL-onlyrdquo condition withldquoMSLrdquo condition also giving a reasonably small deviation of RMC

dirmix from unity On thecontrary the worst performance is associated to the MLL and MUL trigger conditions

The combinatorial background mass shape evaluated for the real data was correctedfor the RMC

dirmix ratio To get rid of the statistical fluctuations due to the limited availableMC sample this ratio is parametrized by the following function before being used tocorrect the data

f(M) = A eminusaM minusB eminusbM +C (54)

where all the parameters are imposed to be positive except C This correction is performedindependently in each (pT y) phase space interval considered in the analysis

513 The Combinatorial Background Estimation

Having validated the method for the evaluation of the combinatorial background it is nowpossible to use it for isolating the dimuon correlated signal in the data Following the resultof the MC validated presented in the previous section the ldquoMSL-onlyrdquo events are used asinput for the event mixing technique The typical mass dependence of the R-factor (ratiobetween the acceptance of LS and OS muon pairs) defined in equation (52) and estimatedas equation (53) is shown in figure 54 for the phase space interval 10 lt pT lt 100 GeVcand minus400 lt y lt minus250 In this same kinematics interval the comparison between theraw dimuon and the combinatorial background is shown in figure 55 The correspondingisolated dimuon correlated signal is shown in figure 56 forMmicromicro lt 100 GeVc2 where thepeaks of the Υ(1S) ψ(2S) and Jψ resonances can be observed and in figure 57 for thelow-mass region where the peaks of the φ and ρω two-body decays are visible togetherwith the structure of the η Dalitz decay

51 Combinatorial Background Evaluation and Subtraction 69

]2c [GeVmicromicroM0 2 4 6 8 10

R

0

02

04

06

08

1

12

lt 1000T

p100 lt

lt - 250y- 400 lt

B TeyssierWork Thesis

Figure 54 The R factor for the data integratedin 10 lt pT lt 100 GeVcand minus400 lt y lt minus250

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 2 4 6 8 10

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

dNd

M

210

310

410

510

610

raw mass spectrum

mass spectrummixOS

B TeyssierWork Thesis

Figure 55 Raw data between 250 lt y lt 400and 10 lt pT lt 100 GeVc

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeVmicromicroM0 2 4 6 8 10

]2 c [d

imuo

ns p

er 2

5 M

eV

micromicrodN

dM

210

310

410

510

610 B TeyssierWork Thesis

Jψ

ψ (2S)

Υ (1S)

Figure 56 Signal after subtraction of combina-torial background in mass range between 02 to100 GeVc2

0 02 04 06 08 1 12 140

01

02

03

04

05

610timesB Teyssier

Work Thesis

ρω

φ

Figure 57 Signal after subtraction of combina-torial background in mass range between 02 to15 GeVc2

70 Chapter 5 Signal Extraction

The combinatorial background estimation and subtraction is particularly challengingat very low pT where the signal-over-background ratio is smaller (as small as asymp 1 at theφ peak) In order to appreciate how the signal can nevertheless be extracted down tovery low pT in figure 58 (top panels) the raw data with the associated combinatorialbackground are shown for 00 lt pT lt 02 GeVc in the rapidity intervals where theacceptance is non-negligible (the most forward region see figures 43 and 47) Thecorresponding isolated signal is shown in the same figure (bottom panels)

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

25310times

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 375 lt y lt 400

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15310times

B TeyssierWork Thesis

(e) 350 lt y lt 375

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310timesB Teyssier

Work Thesis

(f) 375 lt y lt 400

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310timesB Teyssier

Work Thesis

Figure 58 Rapidity evolution of signal and combinatorial background shapes for 00 lt pT lt

02 GeVc

52 Invariant Mass Fit ProcedureAfter subtraction of the uncorrelated background the next step in the analysis is theextraction of the signals of interest from the dimuon correlated invariant mass spectrumin this specific case this means counting how many dimuons from the η rarr micro+microminusγω rarr micro+microminus and φ rarr micro+microminus decays can be extracted from the data for each of the pT-yintervals considered in the analysis For this step the dimuon correlated invariant massspectrum is decomposed into the expected sources composing the hadronic cocktail (two-body and Dalitz decays of light neutral mesons see section 41) via a fit procedure also

52 Invariant Mass Fit Procedure 71

including a description of the correlated continuum component

521 Specific Constraints on the Hadronic Cocktail Compo-nents

In the fit procedure considered in this analysis for the extraction of the signals of interestspecific constraints have been imposed to the components of the hadronic cocktail inorder to reduce the number of degrees of freedom fixing the minor processes (in terms ofreconstructed dimuons) to the major ones Each considered constraint has been also takenas a contribution in the evaluation of the systematics on the signal extraction discussedin section 61

Fixing the relative branching ratios of two-body and Dalitz decays for the ηand ω meson mdash The η and ω mesons contribute to the hadronic cocktail with twodecay channels ηrarr micro+microminusγ and ηrarr micro+microminus for the η and ωrarr micro+microminusπ0 and ωrarr micro+microminus

for the ω Since the branching ratios of each channel is known from the literature thenormalizations of the two-body and Dalitz decay modes can be fixed to each other (as longas the quality of the data does not allow for an independent measurement of the relativebranching ratios) This constraint has been technically implemented for the η meson byconsidering the normalization of the ηrarr micro+microminusγ process has a free parameter and fixingthe ηrarr micro+microminus contribution to it for the ω meson the normalization of the ωrarr micro+microminus

process has been left as a free parameter the contribution of the ω rarr micro+microminusπ0 decaybeing fixed to it For each particle the process associated to the free parameter is the onemore clearly identifiable in the invariant mass profile of the data The relevant branchingratios are listed in tables 42 and 43

Fixing the σηprimeσφ cross-section ratio mdash The contribution of the ηprime Dalitz decayaccounts for a very small fraction of the total reconstructed dimuon mass spectrum forthis reason and because of its continuum shape having no dominant structure apart fromthe broad peak at ρ mass (due to the contribution of the ρ meson to the ηprime form factorsee section 412) the fit procedure is not sensitive to this contribution Consequently thenormalization of the ηprime rarr micro+microminusγ process has been set by fixing the ηprime cross-section tothe cross-section of one of the particles giving a major contribution to the invariant massspectrum namely the φ meson The reference value for the σηprimeσφ cross-section ratio hasbeen evaluated with PHOJET to be 3151 in the rapidity window 25 lt y lt 40 integratedover pT This ratio has been rescaled in each pT-y interval considered in the analysisaccording to the kinematic distributions of the two particles also given by PHOJET

Fixing the σρσω cross-section ratio mdash Due to the broad line shape of the ρ mesonand the limited mass resolution of the detector for the superimposed ω rarr micro+microminus peakthe ρ rarr micro+microminus contribution cannot be easily disentangled in the fit procedure For thisreason the normalization of the ρrarr micro+microminus contribution has been set to the ωrarr micro+microminus

one by fixing the σρσω cross-section ratio The reference value for this ratio has beentaken as 10 from previous measurements [88ndash90]

72 Chapter 5 Signal Extraction

Due to the mass resolution of the ω peak the distinction of the ω and ρ two-bodycontribution is not obvious So it is better to enslave the ρ two-body component to theω to increase the stability of the fit The ratio of the production cross-section of ρω ismeasured to 10 in several previous experiments [88ndash90]

522 Correlated Continuum TreatmentSeveral choices can be considered for the description of the correlated continuum as dis-cussed below As discussed in section 42 the main sources in the correlated dimuoncontinuum are the open charm and beauty processes However as also discussed in sec-tion 42 the evaluation of the MC template of the invariant mass shape of the open charmand beauty dimuons is affected by potentially non-negligible uncertainties according tothe considered input for the cc and bb kinematics and the real degree of correlation of thefinal state muons Moreover one as to consider the possibility of having some residualuncertainty from the combinatorial background subtraction and a possible dimuon com-ponent from correlated light-flavor hadron decays On the basis of these considerationstwo approaches have been tested for the description of the correlated continuum

In the fit process for treating the underlying physics continuum we assume that themain source of this continuum is based on the open heavy-flavor where the way to obtainthe shapes of open charm and beauty are described in section 42 Two possible ways forusing these shapes in the fit process one based on the full description of all processes theother based on a phenomenological approach for the correlated continuum and realisticdescription of processes are considered

The ldquocharm+beautyrdquo approach mdash This approach is based on three assumptions

1 The correlated continuum has only two components open charm and beauty

2 The shapes of the dimuon invariant mass templates for the open charm and beautyprocesses are known with negligible uncertainties (with the same precision as thetemplates for the hadronic cocktail processes)

3 The ratio between the open beauty and the open charm dimuon components isknown (together with its pT and y dependence at the specific energy considered inthe analysis) either from measurements or from tuned models like FONLL or PYTHIA

In this approach the correlated continuum description is associated to one free parameterThe only available measurements for the cc and bb cross-section at forward rapidity comefrom LHCb [3891ndash93] the ratio σbbσcc is (594plusmn 055) middot 10minus2 in good agreement withthe central value of the FONLL prediction (645 middot 10minus2) [86 87]

When considering this approach in the description of the correlated continuum non-negligible tensions between data and MC can be found according to the specific phasespace interval considered These tensions increase towards mid-rapidity while are almostnegligible for the most forward rapidity intervals An example is given in the left-columnplots of figures 59 and 510 where the data-MC comparison is shown for the six y intervals

52 Invariant Mass Fit Procedure 73

considered for the analysis in the pT interval 20 lt pT lt 22 GeVc The same trend isobserved in almost all the considered pT intervals

As a matter of fact these tensions induce an indirect bias on the extraction ofthe signals of interest for the analysis particularly important for the extraction of theω rarr micro+microminus signal For this reason this approach is probably not well-fitted for thisspecific analysis aiming to simultaneously extract the η rarr micro+microminusγ ω rarr micro+microminus andφrarr micro+microminus signals

The semi-empirical approach mdash This new approach has been developed after con-sidering the major limitations of the ldquocharm+beautyrdquo approach in describing the dataover the full rapidity interval available The main difference with respect to the previousapproach is the fact that we abandon any strict physical interpretation of the correlatedcontinuum describing it with an empirical profile flexible enough to saturate the tensionbetween data and MC ensuring a robust extraction of the signals of interest for the anal-ysis This is achieved by describing the correlated continuum by means of two (or more)free parameters each controlling the normalization of an independent empirical shapeThe specific shape of these independent components is not really important still one hasto use sufficiently different mass shapes to ensure enough freedom on the total profile ofthe continuum

Two variants of this semi-empirical approach have been tested in this analysis

bull A 2-component description of the correlated continuum In this case an obviouschoice is to take the two components as the invariant mass distributions of OSdimuons from open charm and open beauty simulations2 This choice allows one tocombine the required smoothness of the continuum invariant mass shape with thekinematical constraints typical of a reconstructed dimuon mass distribution closeto the low-mass threshold this would not have been (easily) achievable with anytrivial combination of analytical parametric functions

bull A 3-component description of the correlated continuum In this variant we add athird component to the two components already considered in the previous case areasonable choice is to take this third component to have the profile of the combi-natorial background evaluated in each pT and y interval considered in the analysis

The results of the data description with these two variants of the semi-empirical ap-proach are shown in figures 59 and 510 in the center and right panels respectively forthe 2- and the 3-component description of the correlated continuum As one can see the2-component description already fixes the tension between data and MC found with theldquocharm+beautyrdquo approach in the full y range Nevertheless the addition of the third de-gree of freedom allowed by the 3-component description of the correlated continuum stillimproves the extraction of the signal in some specific cases see for instance the extractionof the φrarr micro+microminus signal in figures 59b and 59c For this reason the 3-component variantof the semi-empirical approach has been retained as the reference method for the signalextraction for the present analysis

2 It should be clear that in this semi-empirical approach the physical interpretation of any of the twocomponents taken separately is meaningless and must be avoided

74 Chapter 5 Signal Extraction

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 275y250 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 275y250 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 275y250 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 300y275 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 300y275 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 300y275 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(g) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(h) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(i) 300 lt y lt 325

Figure 59 Signal fit for 20 lt pT lt 22 GeVc and various y intervals The first figure of each linecorresponding to the method with the full description of processes the second and third figures ofeach line corresponding to the hybrid method with two or three components respectively

52 Invariant Mass Fit Procedure 75

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6310times

lt 400y375 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(g) 375 lt y lt 400

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6310times

lt 400y375 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(h) 375 lt y lt 400

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6310times

lt 400y375 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(i) 375 lt y lt 400

Figure 510 Signal fit for 20 lt pT lt 22 GeVc and various y intervals The first figure of eachline corresponding to the method with the full description of processes the second and third figuresof each line corresponding to the hybrid method with two or three components respectively

76 Chapter 5 Signal Extraction

523 A Few Examples of Hadronic Cocktail FitsThe detailed breakdown of the MC sources involved in the fit procedure is shown infigure 511 where the data sample considered in the present analysis is integrated over250 lt y lt 400 and 10 lt pT lt 100 GeVc The structures of the η rarr micro+microminusγω rarr micro+microminus and φ rarr micro+microminus processes considered for the estimation of the η ω and φyields are observed to shine out over the underlying continuum Here as well as in thefits presented in the rest of the document the red profile is the sum of the MC sourcesThe uncertainty on the total MC profile is evaluated by combining the uncertainties onthe normalization of each considered source For the processes whose normalization isleft free in the fit this uncertainty is the statistical one resulting from the fit procedureitself for the other processes we propagate the systematic uncertainty on the parameters(branching ratios or cross section ratios) which fix their normalizations to those of thefree processes

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

01

02

03

04

05

610times

γmicromicro

rarrη

γmicromicrorarrη

micromicrorarrη

micromicrorarrρ0πmicromicrorarrω

micromicrorarr

ω

micromicrorarrφ

continuumcorrelated

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

lt 400y250 lt

c lt 1000 GeVT

p100 lt = 13 TeVsALICE pp

lt 40y25 lt

c lt 100 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y250 lt

c lt 1000 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 40y25 lt

c lt 100 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y250 lt

c lt 1000 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

Figure 511 Example of hadronic fit in 250 lt y lt 400 and 10 lt pT lt 100 GeVc

The shape of the dimuon invariant mass spectrum changes significantly according tothe considered pT-y interval In particular at very low-pT and towards central rapiditythe acceptance constraints imposed by the detector deplete the mass spectrum near thekinematic threshold For this reason some of the processes are not measurable in specificregions of the phase space as it could be expected by inspecting the pT-y profiles of the(Atimes ε) reported in figures 43 and 47 In addition at high-pT one observes a decrease ofthe ratio of the hadronic cocktail over the correlated continuum which could be attributedto the decrease of the ratio of the light flavor sources (composing the hadronic cocktail)over the heavy flavor ones (contributing to the correlated continuum) The full evolutionof the dimuon invariant mass spectrum profile as a function of pT and y can be appreciated

52 Invariant Mass Fit Procedure 77

by considering the plots in appendix C In figure 512 we report a few examples illustratingthe discussed point

(a) 00 lt pT lt 02 GeVcand 375 lt y lt 400

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 04 lt pT lt 05 GeVcand 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 20 lt pT lt 22 GeVcand 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

310times

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 40 lt pT lt 45 GeVcand 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 70 lt pT lt 80 GeVcand 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 80 lt pT lt 100 GeVcand 250 lt y lt 275

Figure 512 A few examples of hadronic fit in several pT and y intervals

Chapter 6

Systematics Evaluation

Summary61 Systematics on the Signal Extraction 80

611 Relative Branching Ratio of two-body and Dalitz Decays for the ηand ω Mesons 80

612 σηprimeσφ Cross-Section Ratio 80

613 σρσω Cross-Section Ratio 81

614 Upper limit of the fit 81

615 The correlated continuum shape 81

616 Systematic Uncertainty Computation 82

62 Systematics from the MC input 82

63 Systematics on Trigger Efficiency 83

631 Evaluation of the Trigger Response Function 83

632 Results 84

64 Systematics on Tracking Efficiency 85

641 Preliminary Check 85

642 Tracking Efficiency Evaluation 86

643 MC parametrization 88

644 Results 89

65 Summary of Systematic Uncertainty 89

In this chapter all the systematics sources of the present analysis are presented Twomain groups of systematics uncertainties have been studied

bull the sources contributing to the systematics uncertainty on the signal extraction

bull the sources contributing to the systematics on the (Atimes ε) evaluation

In the first group we include the uncertainties on the parameters involved in thefit procedure (see section 52) relative branching ratios cross-section ratios correlatedcontinuum shape fit range In the second group we include the uncertainties on thekinematic input of the MC simulations on the tracking efficiency and the trigger response

80 Chapter 6 Systematics Evaluation

61 Systematics on the Signal ExtractionIn order to define the systematics tests on the signal extraction a reference scenario hasbeen defined based on the reference values of the parameters involved in the fit procedureFor each parameter one or more alternative values have been considered each systematictest is defined by the variation of one parameter only while the others are kept fixedto their reference value In total 10 systematic tests have been considered the totalsystematic uncertainty on the number of η rarr micro+microminusγ ω rarr micro+microminus and φ rarr micro+microminus

dimuons was taken as the standard deviation of the values resulting from these tests

Syst test reference value alternative value(s)BR ηrarr micro+microminus PDG PDG minus1σ PDG +1σBR ωrarr micro+microminusπ0 PDG PDG minus1σ PDG +1σRatio σηprimeση 0295 minus50 +50Ratio σρσω 10 minus10 +10Upper fit limits 15 GeVc2 20 GeVc2

Templates for thecorrelated contin-uum components

ccrarr micromicro from PYTHIAbbrarr micromicro from PYTHIA

OS from evt mix (data)

ccrarr micromicro from FONLLbbrarr micromicro from FONLL

OS from combinatorial bkg (MC)

Table 61 Summary of systematics tests

611 Relative Branching Ratio of two-body and Dalitz Decaysfor the η and ω Mesons

This systematics test reflects the uncertainty on the ratio between the branching ratio ofthe two-body and Dalitz decay channel of the η and ω mesons In this analysis this testwas implemented by varying the branching ratio of the η rarr micro+microminus and ω rarr micro+microminusπ0

processes by plusmn1σ where σ is the uncertainty on the measurement reported by the PDG(shown in tables 42 and 43) resulting in four independent alternative fits on the data

The variation of the ηrarr micro+microminus branching ratio was found to have a negligible impacton the extraction of η rarr micro+microminusγ and φ rarr micro+microminus signals and a limited impact on theextraction of the ωrarr micro+microminus signal of the order of 1 On the contrary the variation oftheωrarr micro+microminusπ0 branching ratio by plusmn1σ has an average impact of plusmn3 for the extractionof ηrarr micro+microminusγ and ωrarr micro+microminus signals and negligible for the φrarr micro+microminus signals

612 σηprimeσφ Cross-Section Ratio

The ratio σηprimeσφ was varied by plusmn50 to take into account the general lack of mea-surements for this ratio and the differences between the predictions from the availablephenomenological models PYTHIA6 and PHOJET The impact of the considered plusmn50 vari-ation has been observed to be in average ∓2 for the ωrarr micro+microminus signal and negligiblefor the φrarr micro+microminus and ηrarr micro+microminusγ signal

61 Systematics on the Signal Extraction 81

613 σρσω Cross-Section RatioThe uncertainty on the σρσω ratio has been taken from the existing measurements atlower energy [88ndash90] The absence of any strong theoretical argument in favor of animportant energy dependence of this ratio allowed us to take a plusmn10 for the associateduncertainty As expected the impact of this plusmn10 variation is non-negligible only for theextraction of theωrarr micro+microminus signal which is affected by a corresponding ∓2 uncertainty

614 Upper limit of the fitThe lower limit of the invariant mass fit range has been set to the 2mmicro kinematic thresholdin order to be sensitive to the full structure of the η rarr micro+microminusγ decay For the upperlimit a reference value has been set at 15 GeVc2 this value is a trade-off betweenbeing sensitive to the full width of the φ rarr micro+microminus peak and limiting the impact of thecontinuum region between the φ and Jψ resonance where no signal of interest for thelight-neutral mesons can be extracted To study the systematic uncertainty linked to thechoice of the upper limit of the fit range an alternative value has also been defined at20 GeVc2 The corresponding average impact on the extraction of the signals of interestis -3 -12 and -4 respectively for the η rarr micro+microminusγ ω rarr micro+microminus and φ rarr micro+microminus

signals

615 The correlated continuum shape

]2c [GeVmicromicroM0 02 04 06 08 1 12 14

[au

]micromicro

dNd

M

0

5

10

15

20

25

3minus10times

from OS mixing

(PYTHIA)bfrom b

(PYTHIA)cfrom c

(a) Reference

]2c [GeVmicromicroM0 02 04 06 08 1 12 14

[au

]micromicro

dNd

M

0

5

10

15

20

25

3minus10times

microfrom OS MC uncorr

(FONLL)cfrom c

(FONLL)bfrom b

(b) Alternative

Figure 61 Normalized shape of continuum templates

The shape of the correlated continuum is determined by the fit by optimizing therelative weight of three invariant mass templates as explained in section 522 To eval-uate the systematic uncertainty associated to the choice of this set of templates analternative set of templates have been considered The alternative templates correspond

82 Chapter 6 Systematics Evaluation

to the reconstructed open charmbeauty dimuons generated with the lower limit of theFONLL prediction range (offering the largest deviation from the corresponding referencetemplates see figure 412) and to the OS dimuons from the MC simulations of uncor-related muons already considered for the validation of the event mixing technique (seesection 512) Considering the alternative set of templates has an average impact of minus1for the ηrarr micro+microminusγ 2 for the ωrarr micro+microminus and 9 for the φrarr micro+microminus signals

616 Systematic Uncertainty ComputationAs already mentioned the systematic uncertainty on the signal extraction is computedseparately for the η rarr micro+microminusγ ω rarr micro+microminus and φ rarr micro+microminus processes as the standarddeviation of the distribution of value obtained from the systematic tests described above

σ2 = 1N

testssumi

(xi minus 〈x〉)2 (61)

where xi is the outcome of the i-th systematic test out of the N available tests andthe expectation value 〈x〉 is taken as the outcome of the reference fit This approach isjustified by the assumption that for each source of systematics the associated uncertaintycan be assumed to be Gaussian This evaluation is done for each pT-y interval consideredin this analysis

The global uncertainty on the signal extraction is reported in table 62 for the threesignals extracted with the fit procedure since its value depends on the pT and y intervalthe minimum and maximum values are quoted The average uncertainties correspondingto the considered systematic tests on the signal extraction are also reported in the table

Syst test ηrarr micro+microminusγ ωrarr micro+microminus φrarr micro+microminus

BR ηrarr micro+microminus lt 1 2 2 BR ωrarr micro+microminusπ0 3 3 2 Ratio σηprimeσφ lt 1 3 2 Ratio σρσω 1 2 2 Upper fit limit 5 6 8 Templates for the correlatedcontinuum 6 4 5

Standard deviation from (61) 1 - 22 2 - 12 1 - 16

Table 62 Summary of the systematic tests considered on the signal extraction procedure

62 Systematics from the MC inputThe first source of systematic uncertainty considered for the (Atimes ε) evaluation is thechoice of the input kinematic distributions assumed in MC simulations for the generatedη ρ ω ηprime and φ mesons see section 411 The reference choice being the correlated

63 Systematics on Trigger Efficiency 83

pT-y input from PHOJET the alternative MC input has been based on parametrized non-correlated pT and y distributions form PYTHIA6 The corresponding systematic uncer-tainty has been evaluated for each pT and y interval considered in this analysis by takingthe difference of the (Atimes ε) value estimated with the reference and the alternative MCinputs The corresponding average impact on the extraction of the signals of interest is5 55 and 1 respectively for the ηrarr micro+microminusγ ωrarr micro+microminus and φrarr micro+microminus signals

63 Systematics on Trigger Efficiency

The systematics on the trigger efficiency has been determined by comparing the proba-bility of reconstructing dimuons of a given kinematics with two different trigger responsefunctions one obtained from the data and the other from MC simulations The standardprocedure to estimate the systematic uncertainty from the trigger response function canbe summarized as follows

bull Fit the ratio low-pTA-pT obtained dividing the pT distribution of single muonsmatching the low-pT trigger condition by the pT distribution of single muons match-ing the A-pT condition (see paragraph e on section 223) This ratio is evaluatedboth in data and in realistic MC simulations and the corresponding fits define thetrigger response function

bull Select muons matching the A-pT trigger condition in the MC simulation of a specificdimuon signal and weigh each of them (according to their pT) by either the dataor the MC trigger response function

bull Extract the number of reconstructed dimuons under the two assumptions of thetrigger response function The difference is the systematics uncertainty of the triggerefficiency

631 Evaluation of the Trigger Response Function

The definition of the trigger response function given above cannot be used in the presentanalysis because in the considered data set the low-pT and the A-pT trigger matchingconditions coincide Therefore an alternative definition of the trigger response function isadopted here namely the ratio low-pTAll where the denominator is the pT distributionof All reconstructed muons imposing no trigger matching condition

Unfortunately this new definition of the trigger response function cannot be safelyapplied to the data because the All muon sample is contaminated by a non-negligiblehadronic component In this case one can still estimate the low-pTAll for the datastarting from the ratio of the corresponding MC ratio through a dataMC conversionfactor This conversion factor is defined as the ratio between the trigger response functionslow-pTA-pT of data and MC estimated in a dataset (B) as close as possible to the one(A) considered in the present analysis and characterized by different thresholds for the

84 Chapter 6 Systematics Evaluation

low-pT and A-pT trigger matching conditions

low-pT

All

∣∣∣∣∣data

A

(pT) = low-pT

All

∣∣∣∣∣MC

A

(pT)timeslow-pTA-pT

∣∣∣dataB

(stimes pT)low-pTA-pT

∣∣∣MC

B(stimes pT)

(62)

with the pT dependence of the trigger response functions in the reference dataset B beingldquostretchedrdquo by the s factor

s = pcutT (MC B)pcutT (MC A) (63)

where pTcut(MC x) is defined as the pT value for which the trigger response function

(low-pTAll or low-pTA-pT respectively for the datasets A and B) reaches half the dif-ference between the maximum and minimum This approach is correct as long as twoassumptions are valid

bull the trigger response per local board does not change with time

bull the relative difference dataMC between the low-pTA-pT trigger response func-tions from data and MC does not change when considering the low-pTAll triggerresponse functions

The low-pTA-pT trigger response functions defining the dataMC conversion factorin equation (62) can be replaced by a parametrization given by the function

F (pT pcutT σ) = 1 + p0 times

erfpT minus pcut

Tsradic

2σs

minus 1 (64)

based on the three free parameters p0 pcutT and σIn the present analysis the reference dataset B has been assumed to be the 2015 Pb-Pb

dataset (restricted to the peripheral collisions in the 60-100 centrality class) taken atradics = 502 TeV this choice is also used in other dimuon analyses based on the pp dataset

atradics = 5 TeV and the p-Pb dataset at radicsNN = 5 mdash 816 TeV

632 ResultsThe two versions of the trigger re-weighting described above produced two alternativeestimations of the (Atimes ε) for the three considered processes For each pT-y cell consideredin the analysis we retained the alternative version giving the largest deviation with respectto the reference value this deviation is shown in the form of a ratio in figure 62 Theabsolute deviation of this ratio is taken as the systematic uncertainty on the triggerefficiency the average values of this uncertainty are 2 06 and 1 respectively forthe ηrarr micro+microminusγ ωrarr micro+microminus and φrarr micro+microminus processes In the analysis this uncertaintyhas been evaluated for each specific pT-y cell considered for the extraction of the signalSystematic uncertainty values as large as 30 were tolerated in this analysis this resultedin the exclusion of the (minus350 lt y lt 325 04 lt pT lt 06 GeVc) interval for theηrarr micro+microminusγ signal affected by a systematic on the trigger efficiency larger than 70

64 Systematics on Tracking Efficiency 85

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

06

07

08

09

1

11

12

13

14 RefTrigg-reweight

γmicromicrorarrη ]εtimes[ A

(a) ηrarr micro+microminusγ

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

06

07

08

09

1

11

12

13

14 RefTrigg-reweightmicromicrorarrω ]εtimes[ A

(b) ωrarr micro+microminus

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

06

07

08

09

1

11

12

13

14 RefTrigg-reweight

micromicrorarrφ ]εtimes[ A

(c) φrarr micro+microminus

Figure 62 Ratio of Atimes ε for original simulation over the re-weighted simulation for estimating thesystematics associated to the trigger efficiency

64 Systematics on Tracking Efficiency

The systematics on tracking efficiency is one of the contributions to the uncertainty on the(Atimes ε) estimation To compute this uncertainty one has to evaluate the ratio betweenthe tracking efficiencies of data and MC

641 Preliminary Check

Before studying the tracking efficiencies in data and MC it must be verified that thestatus of the detector described in the realistic MC simulations is compatible with thestatus of the detector reflected by the data This is done by inspecting the cluster mapsof the tracking chambers in data and MC in this way one can verify whether the deadareas in the data are correctly reproduced in the MC and no additional dead area isintroduced An example of such comparison is shown in figure 63

Another point to be checked is the variation of the high voltage supplied to the track-ing chambers with respect to the value 16 kV corresponding to the nominal operatingconditions During Run 2 indeed some frequent high voltage drops to 14 kV were spot-ted resulting in a degraded efficiency of the chambers Since this intermediate behaviorbetween the full operation and the off status cannot be easily reproduced in MC specificdetector elements being significantly affected by high voltage drops are added to a ldquorejectlistrdquo and excluded from the reconstruction both in data and MC Alternatively when thispathological high voltage behavior only affects a limited fraction of the considered datasample full runs can be excluded it was the case in the present analysis where 4 runsof the LHC16n period were rejected to avoid major discrepancies between data and MC

After checking the agreement between data and MC concerning the detector statusand the behavior of the high voltage it is possible to launch the evaluation of the trackingefficiency both in data and MC

86 Chapter 6 Systematics Evaluation

Figure 63 Comparison between cluster maps of tracking chamber 4 in data (left) and MC (right)

642 Tracking Efficiency EvaluationThe tracking efficiency (εglobal) is computed as the product of the efficiency (εSti) of eachtracking station

εglobal = εSt1 middot εSt2 middot εSt3 middot εSt45 (65)

The fact the efficiencies of stations 4 and 5 are combined together in the efficiency εSt45 isdue to the logic operating mode implemented in the tracking algorithm [7894] requiringone cluster per station for stations 1 2 and 3 and three clusters from the combinedstations 4-5

Ch1 Ch2 Ch3 Ch4 Ch5 Ch6 Ch7 Ch8 Ch9 Ch10

NSt21-1

St1 St2 St3 St4 St5

NSt20-1

NSt21-0

NSt20-0

St45

Figure 64 Sketch showing the arrangement of the chambers into stations and the possible responsesof one station to the passage of a particle

64 Systematics on Tracking Efficiency 87

To evaluate the efficiency of a given station one has to start considering the efficiencyof the chamber composing the station (see section 223 for a more detailed description ofthe muon spectrometer structure) To evaluate the efficiency of each tracking chamberthe assumption is done that its efficiency does not depend on the efficiency of the otherchambers under this assumption the redundancy of the information given by the twochambers of a specific station can be used to determine the efficiency of each chamberseparately Figure 64 shows the possible responses of station 2 to the passage of aparticle Generalizing to the case of an arbitrary station k the reconstructed track canhave a cluster in both chambers (NStk

1-1 ) a cluster either in the first or the second of thetwo stations (NStk

1-0 or NStk0-1 ) or the track does not fulfill the tracking conditions so it is not

reconstructed (NStk0-0 ) Still focusing on station k composed of chamber i and j(= i+ 1)

one can express the number of reconstructed tracks (Ntot each of them crossing stationk due to the conditions imposed by the tracking algorithm) as

Ntot = NStk1-1 +NStk

0-1 +NStk1-0 (66)

Under the assumption that the efficiencies of chambers i and j are independent NStk1-1

NStk1-0 and NStk

0-1 can be expressed as a function of Ntot

NStk1-1 = Ntot middot εChi middot εChj (67)

NStk1-0 = Ntot middot εChi middot (1minus εChj) (68)

NStk0-1 = Ntot middot (1minus εChi) middot εChj (69)

By combining the above equations the efficiencies of chamber i and j are given by

εChi = NStk1-1

NStk1-1 +NStk

0-1εChj = NStk

1-1NStk

1-1 +NStk1-0

(610)

The individual chamber efficiencies can be combined to compute the efficiency of eachstation In the case of the first three stations the efficiency is defined as the probabilityfor a muon to be detected by at least one of the two chambers

εSt1(23) = 1minus(1minus εCh1(35)

) (1minus εCh2(46)

)= εCh1(35) εCh2(46) +

(1minus εCh1(35)

)εCh2(46) + εCh1(35)

(1minus εCh2(46)

) (611)

For the last two stations the efficiency has to be calculated as a whole due to the trackingalgorithm requirements This efficiency is the probability that a muon is detected by atleast three out of the four chambers in the stations the corresponding formula is thegeneralization of equation (611)

εSt45 =10prodi=7

εChi +10sumi=7

(1minus εChi)10prodj=7j 6=i

εChj

(612)

88 Chapter 6 Systematics Evaluation

643 MC parametrization

In order the tracking efficiency estimation in the MC to be reliable the considered para-metric muon generator must be tuned in order to reproduce the reconstructed kinematicsof the single muons measured in pp collisions at

radics = 13 TeV considered in the present

analysis The tuning is performed by means of a recursive procedure illustrated in fig-ure 65 which includes the following steps

1 Run MC simulations of single muons with given input pT and y distributions

2 Compute the (Atimes ε) as a function of pT and y

3 Use the (Atimes ε) to correct the reconstructed muon distributions from data

4 Compute the ratio as a function of both pT and y between the corrected datadistribution and the kinematic distributions considered for the MC input Shouldthis ratio be compatible with one convergence is reached and the procedure isstopped

5 Inject the corrected pT and y data distributions as the new input for MC simulation

until step 4 is equal to one

First Set of MC simulation

MC gen distribMC rec distrib

MC (Atimes ε)Rec

data distrib

Data corr distrib

Datacoor distrib =MC gen distrib

Data corr distrib rarr MC gen distrib

Done

1

2

3 34

No

Yes

51

Figure 65 Illustration of the data driven method used to tune the input distribution of single muon

65 Summary of Systematic Uncertainty 89

644 ResultsTracking efficiency estimations from the data and from the tuned MC simulation areshown in figure 66 as a function of pT y the azimuthal angle ϕ and the run number A2 systematic uncertainty is observed in average for single muon from the comparisonbetween data and MC For the dimuon signals the systematic uncertainty on the trackingefficiency is estimated to be twice the systematics on the single muons in this case thisresults in a 4 systematic uncertainty independent of pT and y

run number

2536

59

2541

28

2543

78

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

effic

ienc

y

0

02

04

06

08

1

Simulation Data

run number2536

59

2541

28

2543

78

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

EffD

ata

EffS

im

09

1

11

B TeyssierWork Thesis

Figure 66 Tracking efficiency measured in data and in the tuned MC simulation as a function ofrun number

65 Summary of Systematic UncertaintyIn table 63 are summarized the various sources of systematic uncertainties discussed inthis chapter For each of these sources and each signal of interest for this analysis wereport the value of the systematic uncertainty when the uncertainty values depend onthe pT or the y interval their maximum and minimum values are quoted

Syst source η ω φ

Signal extraction 1 - 22 2 - 12 1 - 157 MC input 5 55 1 Trigger efficiency 1 - 31 1 - 24 1 - 25 Branching ratio 13 2 1 Tracking efficiency 4 Luminosity 5

Table 63 Summary of the systematic uncertainty sources contributing to the measurement of theη ρω and φ meson cross-section

Chapter 7

Light Neutral Meson Production

Summary71 Estimation of the Number of Generated Mesons 91

711 The Two-Body Decay Case 91712 The Dalitz Decay Case 92

72 Cross-Section Production for Light Neutral Mesons 93

721 Double-Differential η Meson Production 93722 ρω Meson Production 94723 Double-Differential φ Meson Production 98

This chapter describes the steps followed to convert the reconstructed signal into cross-section for the η ρω and φ mesons The pT dependence of the production cross-sectionis extracted in six y intervals and compared to the predictions of the available modelsIn the case of the φ and ρω mesons the pT dependence of the rapidity-integratedcross-section is also derived allowing for the comparison with the results from existingmeasurements in pp collisions in the same rapidity range

71 Estimation of the Number of Generated MesonsThe very first step after signal extraction consists in correcting the number of recon-structed dimuons for the Atimesε evaluated with the MC simulations discussed in section 41In the case of the two-body decays ρω rarr micro+microminus and φ rarr micro+microminus the information onthe dimuons can be directly converted into the corresponding information on the parentmesons by correcting for the branching ratios of the involved decays In the case of theDalitz decay ηrarr micro+microminusγ an additional step is required to convert the dimuon kinematicsto the η meson one before correcting for the branching ratio

711 The Two-Body Decay CaseAs far as the two-body decays of the ρω and φ mesons are concerned the corrected num-ber of mesons (Nρω and Nφ respectively) corresponding to the reconstructed dimuonsN recmicromicro is given for each pT-y interval considered in this analysis by the following formula

Nρω φ(pT y) =N recmicromicro (pT y)

[Atimes ε]micromicro (pT y) middotBRmiddot ∆pT middot ∆y (71)

92 Chapter 7 Light Neutral Meson Production

where [Atimes ε]micromicro (pT y) is the product of the acceptance and the dimuon reconstructionefficiency evaluated in the specific pT-y cell BR is the branching ratio of the considereddecay channel (see table 43) and ∆pT middot ∆y are the widths of the pT-y cell For theestimation relative to the ρω mesons N rec

micromicro (pT y) [Atimes ε]micromicro (pT y) and the BR arereferred to the ωrarr micro+microminus decay

712 The Dalitz Decay Case

When dealing with the Dalitz decay of the η we start by correcting the number ofreconstructed dimuons for the Atimes ε and the widths of the considered pT-y cell

Ngenmicromicro (pT y) =

N recmicromicro (pT y)

[Atimes ε]micromicro (pT y) middot ∆pT middot ∆y (72)

Contrary to the two-body case the corrected kinematics distribution of the dimuon doesnot coincide with the one of the parent meson due to the Dalitz decay kinematics implyinga third body

)ηyηT

pId(0 50 100 150 200 250 300

)micromicroymicromicro T

pId

(

0

50

100

150

200

250

300

1

10

210

310

410

510

610

710

810

)micromicroy micromicroT

p ηy ηT

pT(

Figure 71 Correlation matrix T(pηT yη pmicromicroT ymicromicro) represented in cell coordinates

72 Cross-Section Production for Light Neutral Mesons 93

So to obtain the correct kinematic distributions of the parent η meson an additionaltransformation is needed

Nηrarrmicromicroγ(pT y) = Tminus1 middot Ngenmicromicro (pT y) (73)

where Tminus1 is the inverse of the matrix encoding the correlation between the kinematics ofthe parent η meson and the one of the dimuon both expressed in terms of pT and y TheT(pηT yηp

micromicroT y

micromicro) is shown in figure 71 each T(pηT yη pmicromicroT y

micromicro) element of the matrix isdefined as the probability of an η meson with a given (pηT yη) kinematics to produce adimuon with a given (pmicromicroT ymicromicro) kinematics so that one can write

Ngenmicromicro (pT y) = Tmiddot Nηrarrmicromicroγ(pT y) (74)

from which equation (73) is derived The row-column indexes of the elements of theTmatrix identify a specific pηT yη and pmicromicroT ymicromicro cell respectively In this specific analysisthe phase space limits considered for both the η and the dimuon are 20 lt y lt 45 and00 lt pT lt 150 GeVc in this way any possible edge effect affecting the numericalproblem will have a limited impact on the phase space covered by the available data

Once the correction expressed by equation (73) is performed the resulting kinematicdistribution is further scaled for the η rarr micro+microminusγ branching ratio in order to obtain thecorrect normalization for the Nη(pT y) distribution

72 Cross-Section Production for Light NeutralMesons

The Nηρωφ(pT y) distributions obtained after correcting for the Atimesε and the branchingratio (and for the meson-dimuon kinematic correlation in the case of the η) must be furthernormalized to the integrated luminosity Lint corresponding to the analyzed data sample(the evaluation of the integrated luminosity is discussed in section 32) This normalizationallows one to obtain the cross-section for the three mesons

d2σ(pT y)dpTdy = Nηρωφ(pT y)times 1

Lint (75)

721 Double-Differential η Meson Production

In figure 72 the pT distributions of the dimuon coming from the η rarr micro+microminusγ decay areshown for the six y interval considered in this analysis These distributions representthe Ngen

micromicro (pT y) input from which the kinematic distribution of the parent meson can beextracted via equation (73) The implementation in the current analysis of the kinematiccorrection based on equation (73) is however still under way for this reason no resulton the η meson cross-section is shown in the rest of the chapter

94 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

ydT

pd η

dN

510

710

910

1110

13100250 lt y lt 275 x 101275 lt y lt 300 x 102300 lt y lt 325 x 103325 lt y lt 350 x 104350 lt y lt 375 x 105375 lt y lt 400 x 10

B TeyssierWork Thesis

Figure 72 Comparison of the pT distribution of η dimuon generated as a function of y

722 ρω Meson ProductionFor the ρω mesons the double-differential pT-y production cross-section has been eval-uated in the available phase space the results are shown in figure 73 as a function ofpT in six y intervals For each y interval the measured cross-section has been comparedto the predictions of PYTHIA8-Monash2013 [95] and PHOJET The comparison is shown inthe panels of figure 74 the two models systematically overestimate by a factor sim 2 thedata in the full accessible pT range for each of the considered y intervals

In figure 75 the y dependence of the production cross-section is shown integratedover the pT range 20 lt pT lt 65 GeVc common to the considered y intervals Thecomparison with the predictions from PYTHIA8-Monash2013 and PHOJET confirms thatthe models overestimate the data by a factor sim 2 Besides the global overestimation thePHOJET prediction seems to provide a better description than PYTHIA8-Monash2013 of they dependence of the data

The ρω production cross-section was also measured in ALICE in pp collisions atradics =

7 TeV integrated over 25 lt y lt 40 as a function of pT in the 10 lt pT lt 50 GeVcrange In order to compare our data to the ones at

radics = 7 TeV the production cross-

section measured in this analysis has been integrated over the full accessible 25 lt y lt 40range As it can be seen from figure 73 the integration over 25 lt y lt 40 was possiblelimited to the 20 lt pT lt 65 GeVc range The comparison between the two energiesshows that the 13 TeV cross-section is larger than the 7 TeV one by a factor sim 2 seefigure 76

72 Cross-Section Production for Light Neutral Mesons 95

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

210

310

410

510

610

0250 lt y lt 275 x 10

1275 lt y lt 300 x 10

2300 lt y lt 325 x 10

3325 lt y lt 350 x 10

4350 lt y lt 375 x 10

5375 lt y lt 400 x 10

B TeyssierWork Thesis

Figure 73 Comparison of the pT distribution of ω meson as a function of y

96 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

375 lt y lt 400

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

3minus10

2minus10

1minus10

1

10350 lt y lt 375

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

325 lt y lt 350

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

300 lt y lt 325

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

275 lt y lt 300

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

250 lt y lt 275

Pythia8

PHOJETB Teyssier

Work Thesis

Figure 74 pT distributions of ω meson for various y intervals

72 Cross-Section Production for Light Neutral Mesons 97

y4minus 2minus 0 2 4

[mb]

yωσd

0

05

1

15

2

25

3

(reflected)ω

(measured)ω

Pythia8 - monash2013

Phojet

c lt 65 GeVT

p20 lt

B TeyssierWork Thesis

Figure 75 y distribution of ω meson integrated in 20 lt pT lt 65 GeVc

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσ2 d

3minus10

2minus10

1minus10

1

=7TeVspp at

=13TeVspp at

B TeyssierWork Thesis

Figure 76 pT distribution of ω meson integrated in y and comparison with measurements at7 TeV [43]

98 Chapter 7 Light Neutral Meson Production

723 Double-Differential φ Meson ProductionAs for the ρω mesons the double-differential pT-y production cross-section has beenevaluated for the φ meson too in the available phase space the results are shown infigure 77 as a function of pT in the y intervals considered in the analysis extended at mid-rapidity with the φ rarr K+Kminus measurements [96] The comparison of the data with thepredictions of the PYTHIA8-Monash2013 and PHOJET models is shown for each y intervalconsidered in the analysis in the panels of figure 78 contrary to what observed for theω meson the PYTHIA8-Monash2013 prediction provides a good description of the dataThe PHOJET prediction on the contrary still slightly fails in estimating the normalizationand the shape of the pT dependence of the production cross-section

The y dependence of the production cross-section is shown in figure 79 integratedover the pT range 20 lt pT lt 65 GeVc common to the considered y intervals As one cansee the data points sit between the predictions from PYTHIA8-Monash2013 and PHOJETwhich both slightly fail in describing the shape of the y dependence The results for theφ meson production in the dikaon channel provide an additional point at mid-rapiditywhich could be compared to the forward measurements presented here

Results for the φ meson production cross-section are also available from ALICE mea-surements in pp collisions at

radics = 276 502 7 and 8 TeV integrated over 25 lt y lt 40

as a function of pT in various pT ranges In order to compare our data to the ones atlower energies the φ meson production cross-section measured in this analysis has beenintegrated over the full accessible 25 lt y lt 40 range As it can be seen from figure 77this integration was possible limited to the 20 lt pT lt 65 GeVc range As expected thecross-section at 13 TeV is found to be larger than the measurements at lower energies

The energy dependence of the φ meson production cross-section has been studiedintegrating the present measurement over the y and pT ranges 25 lt y lt 40 and15 lt pT lt 50 GeVc common to the data at the various available energies Theresults are shown in figure 711 compared with the PYTHIA8-Monash2013 and PHOJETprediction the trend as a function of

radics is found to be approximately linear in the con-

sidered energy range with the PHOJET model in good agreement with the data and thePYTHIA8-Monash2013 prediction systematically underestimating the results The analysisstrategy at 13 TeV is being slightly revised in order to reduce the systematic uncertaintyassociated to the integrated cross-section by optimizing the integration procedure namelyintegrating over the rapidity before signal extraction

72 Cross-Section Production for Light Neutral Mesons 99

]c [GeVT

p0 2 4 6 8 10 12

)]c [m

b(G

eV

ydT

pd φσd

4minus10

3minus10

2minus10

1minus10

1

10

210

310

410

510

-1|lt05 x 10y |-

K+ Krarrφ0250 lt y lt 275 x 10

1275 lt y lt 300 x 10

2300 lt y lt 325 x 103325 lt y lt 350 x 10

4350 lt y lt 375 x 10

5375 lt y lt 400 x 10

B TeyssierWork Thesis

Figure 77 Comparison of the pT distribution of φ meson as a function of y extended at mid-rapidityby the φrarr K+Kminus measurements [96]

100 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1375 lt y lt 400

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

350 lt y lt 375

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1325 lt y lt 350

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

300 lt y lt 325

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

275 lt y lt 300

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

250 lt y lt 275

Pythia8

PHOJETB Teyssier

Work Thesis

Figure 78 pT distribution of φ meson for various y intervals

72 Cross-Section Production for Light Neutral Mesons 101

y4minus 2minus 0 2 4

[mb]

y φσd

0

01

02

03

04

05

(refkected)φ (dikaon measurement)φ (measured)φ

Pythia8 - monash2013

Phojet

c lt 65 GeVT

p20 lt

B TeyssierWork Thesis

Figure 79 y distribution of φ meson integrated in 20 lt pT lt 65 GeVc extended at mid-rapidityby the φrarr K+Kminus measurements [96]

102 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσ2 d

3minus10

2minus10

1minus10

1 =276TeVspp at

=5TeVspp at

=7TeVspp at

=8TeVspp at

=13TeVspp at

lt 40y25 lt

B TeyssierWork Thesis

Figure 710 φ meson pT distribution integrated over 25 lt y lt 40 in pp collisions atradics = 13 TeV

(this analysis) compared to previous measurements at lower energies

72 Cross-Section Production for Light Neutral Mesons 103

B TeyssierWork Thesis

Figure 711 Energy dependence of the φ meson production cross-section in 25 lt y lt 40 and15 lt pT lt 50 GeVc

Conclusions and Perspectives

This work focused on the study of the production cross-section of the η ρω and φmesons This study has been achieved by performing a double-differential pT-y analysisin the phase space available for each meson Results have been compared to the availabletheoretical predictions from the PYTHIA8 and PHOJET models this comparison resultedin a better datamodel agreement for the φ meson than for the ρω meson Moreoverexisting results at several lower collision energies in the same y interval allowed toinvestigate the energy evolution of the production cross-section for the φ meson andlimited to the comparison with the

radics = 7 TeV results for the ρω mesons For the φ

meson the energy evolution of the production cross-section integrated over 25 lt y lt 40and 15 lt pT lt 50 GeVc was found to be approximately linear with the PHOJET modelin good agreement with the data and the PYTHIA8-Monash2013 prediction systematicallyunderestimating the results In a next future the results for the φ meson from thepresent analysis could also be compared to the mid-rapidity measurement performed inALICE in the dikaon channel

The present analysis did not exploit the full potential of the large data sample availablein pp collisions at

radics = 13 TeV which could possibly profit from the combination of the

2016 and 2017 data taking Among the measurements which could still be performedbased on the analysis of the low-mass dimuon region one can cite

bull the study of the multiplicity dependence of the light-neutral meson production

bull the search for strangeness enhancement collective phenomena and azimuthalanisotropies in light-neutral meson production in high-multiplicity pp events

bull the study of the light-neutral meson polarization

Finally beyond the standard dimuon analyses the large pp data sample atradics = 13 TeV

could also be exploited for the search of the first evidence of the η rarr 2micro+2microminus decayfor which only an upper limit is currently available from literature [4] The proximity ofthe η meson mass to the 4mmicro threshold makes the observation of this decay particularlychallenging and sensitive to the description to the combinatorial background

Appendix A

List of Runs

000253659 000253680 000253682 000253748 000253751 000253755 000253756 000253757000253813 000253819 000253825 000253826 000253832 000253834 000253951 000253956000253957 000253958 000253961 000253978

Table A1 Run list for period LHC16f

000254128 000254147 000254148 000254149 000254174 000254175 000254178 000254193000254199 000254204 000254205 000254293 000254302 000254304 000254331 000254332

Table A2 Run list for period LHC16g

000254378 000254381 000254394 000254395 000254396 000254419 000254422 000254476000254479 000254604 000254606 000254608 000254621 000254629 000254630 000254632000254640 000254644 000254646 000254648 000254649 000254651 000254652 000254653000254654 000254983 000254984 000255008 000255009 000255010 000255042 000255068000255071 000255073 000255074 000255075 000255076 000255079 000255082 000255085000255086 000255091 000255111 000255154 000255159 000255162 000255167 000255171000255173 000255176 000255177 000255180 000255182 000255240 000255242 000255247000255248 000255249 000255251 000255252 000255253 000255255 000255256 000255275000255276 000255280 000255283 000255350 000255351 000255352 000255398 000255402000255415 000255440 000255442 000255447 000255463 000255465 000255466 000255467000255469

Table A3 Run list for period LHC16h

000255515 000255533 000255534 000255535 000255537 000255538 000255539 000255540000255542 000255543 000255577 000255583 000255591 000255592 000255614 000255615000255616 000255617 000255618

Table A4 Run list for period LHC16i

108 Appendix A List of Runs

000256146 000256147 000256148 000256149 000256156 000256157 000256158 000256161000256169 000256204 000256207 000256210 000256212 000256213 000256215 000256219000256222 000256223 000256227 000256228 000256231 000256281 000256282 000256283000256284 000256287 000256289 000256290 000256292 000256295 000256297 000256298000256302 000256307 000256311 000256356 000256357 000256361 000256362 000256363000256364 000256365 000256366 000256368 000256372 000256373 000256415 000256417000256418 000256420

Table A5 Run list for period LHC16j

000256504 000256506 000256510 000256512 000256552 000256554 000256556 000256557000256560 000256561 000256564 000256565 000256567 000256589 000256591 000256592000256619 000256620 000256658 000256676 000256677 000256681 000256684 000256691000256694 000256695 000256697 000256941 000256942 000256944 000257011 000257012000257021 000257026 000257028 000257071 000257077 000257080 000257082 000257083000257084 000257086 000257092 000257095 000257224 000257260 000257318 000257320000257322 000257330 000257358 000257364 000257433 000257457 000257468 000257474000257487 000257488 000257490 000257491 000257492 000257530 000257531 000257540000257541 000257560 000257561 000257562 000257563 000257564 000257565 000257566000257587 000257588 000257590 000257592 000257594 000257595 000257601 000257604000257605 000257606 000257630 000257632 000257635 000257636 000257642 000257644000257682 000257684 000257685 000257687 000257688 000257694 000257697 000257724000257725 000257727 000257733 000257734 000257735 000257737 000257892 000257893000257901 000257912 000257932 000257936 000257937 000257939 000257957 000257958000257960 000257963 000257979 000257986 000257989 000258008 000258012 000258014000258017 000258019 000258039 000258041 000258042 000258045 000258048 000258049000258059 000258060 000258062 000258063 000258107 000258108 000258109 000258113000258114 000258117 000258178 000258197 000258202 000258203 000258204 000258256000258257 000258258 000258270 000258271 000258273 000258274 000258278 000258280000258299 000258301 000258302 000258303 000258306 000258307 000258332 000258336000258359 000258387 000258388 000258391 000258393 000258399 000258426 000258452000258454 000258456 000258477 000258498 000258499 000258537

Table A6 Run list for period LHC16k

000258919 000258920 000258921 000258923 000258931 000258962 000258964 000259086000259099 000259117 000259118 000259162 000259164 000259204 000259261 000259263000259264 000259269 000259270 000259271 000259272 000259273 000259274 000259302000259303 000259305 000259307 000259334 000259339 000259340 000259341 000259342000259378 000259379 000259381 000259382 000259394 000259395 000259396 000259469000259471 000259477 000259649 000259650 000259668 000259697 000259700 000259703000259704 000259705 000259711 000259713 000259750 000259751 000259756 000259788000259789 000259822 000259841 000259842 000259860 000259866 000259867 000259868000259888 000259954 000259961 000259979 000260010 000260011 000260014

Table A7 Run list for period LHC16l

109

000260218 000260240 000260310 000260312 000260313 000260338 000260340 000260351000260354 000260357 000260379 000260411 000260432 000260435 000260437 000260440000260441 000260447 000260471 000260472 000260475 000260476 000260481 000260482000260487 000260490 000260495 000260496 000260497 000260537 000260539 000260540000260541 000260542 000260564 000260586 000260611 000260613 000260614 000260615000260616 000260647

Table A8 Run list for period LHC16m

000260649 000260650 000260657 000260667 000260671 000260672 000260689 000260691000260693 000260695 000260700 000260704 000260710 000260713 000260722 000260723000260727 000260728 000260740 000260741 000260749 000260750 000260751 000260752000260763 000260770 000260777 000260782 000260784 000260786 000260788 000260804000260808 000260809 000260810 000260815 000260913 000260914 000260920 000260934000260935 000260936 000260938 000260960 000260963 000260992 000260993 000261020000261022 000261025 000261026 000261027 000261052 000261055 000261065 000261076000261083 000261088 000261093 000261094 000261095 000261099 000261100

Table A9 Run list for period LHC16n

000262399 000262418 000262419 000262422 000262423 000262424 000262428 000262430000262451 000262487 000262492 000262528 000262532 000262533 000262537 000262563000262567 000262568 000262569 000262570 000262571 000262572 000262574 000262578000262583 000262593 000262594 000262628 000262632 000262635 000262705 000262706000262713 000262717 000262719 000262723 000262725 000262727 000262760 000262768000262776 000262777 000262778 000262841 000262842 000262844 000262847 000262849000262853 000262855 000262858 000263332 000263487 000263490 000263496 000263497000263647 000263652 000263653 000263654 000263657 000263662 000263663 000263682000263689 000263690 000263691 000263737 000263738 000263739 000263741 000263743000263744 000263784 000263785 000263786 000263787 000263790 000263792 000263793000263803 000263810 000263813 000263823 000263824 000263829 000263830 000263861000263863 000263866 000263905 000263916 000263917 000263920 000263923 000263977000263978 000263979 000263981 000263984 000263985 000264033 000264035

Table A10 Run list for period LHC16o

000264076 000264078 000264082 000264085 000264086 000264109 000264110 000264129000264137 000264138 000264139 000264164 000264168 000264188 000264190 000264194000264197 000264198 000264232 000264233 000264235 000264238 000264259 000264260000264261 000264262 000264264 000264265 000264266 000264267 000264273 000264277000264279 000264281 000264305 000264306 000264312 000264336 000264341 000264345000264346 000264347

Table A11 Run list for period LHC16p

Appendix B

Raw-Background Comparison mdashfigures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150

lt 275y250 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 300y275 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 325y300 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

25310times

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B1 Evolution of signal and combinatorial background shapes for 000 lt pT lt 020 GeVc

112 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

lt 275y250 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 300y275 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 325y300 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 375y350 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 400y375 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B2 Evolution of signal and combinatorial background shapes for 020 lt pT lt 040 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 275y250 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5

310times

lt 300y275 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20310times

lt 325y300 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 400y375 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B3 Evolution of signal and combinatorial background shapes for 040 lt pT lt 060 GeVc

113

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 275y250 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 300y275 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 325y300 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

80310times

lt 375y350 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 400y375 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B4 Evolution of signal and combinatorial background shapes for 060 lt pT lt 080 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 275y250 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8310times

lt 300y275 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 325y300 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 350y325 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

80310times

lt 375y350 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

50

310times

lt 400y375 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B5 Evolution of signal and combinatorial background shapes for 080 lt pT lt 100 GeVc

114 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600 lt 275y250 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 300y275 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 325y300 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 350y325 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60310times

lt 375y350 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 400y375 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B6 Evolution of signal and combinatorial background shapes for 100 lt pT lt 120 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 275y250 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 300y275 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

50310times

lt 325y300 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

310times

lt 350y325 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

310times

lt 375y350 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

50310times

lt 400y375 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B7 Evolution of signal and combinatorial background shapes for 120 lt pT lt 160 GeVc

115

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4310times

lt 275y250 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 300y275 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 325y300 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 375y350 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 400y375 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B8 Evolution of signal and combinatorial background shapes for 160 lt pT lt 200 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5310times

lt 275y250 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 300y275 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20310times

lt 350y325 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 375y350 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

310times

lt 400y375 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B9 Evolution of signal and combinatorial background shapes for 200 lt pT lt 240 GeVc

116 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 275y250 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

310times

lt 300y275 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12310times

lt 325y300 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

310times

lt 375y350 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5

310times

lt 400y375 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B10 Evolution of signal and combinatorial background shapes for 240 lt pT lt 280 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 275y250 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 300y275 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 325y300 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5

310times

lt 350y325 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 375y350 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3310times

lt 400y375 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B11 Evolution of signal and combinatorial background shapes for 280 lt pT lt 320 GeVc

117

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25310times

lt 275y250 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 300y275 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 325y300 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 350y325 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 375y350 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 400y375 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B12 Evolution of signal and combinatorial background shapes for 320 lt pT lt 360 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 275y250 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 300y275 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3310times

lt 325y300 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 350y325 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 375y350 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 400y375 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B13 Evolution of signal and combinatorial background shapes for 360 lt pT lt 400 GeVc

118 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 300y275 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 325y300 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 350y325 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 375y350 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800

lt 400y375 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B14 Evolution of signal and combinatorial background shapes for 400 lt pT lt 450 GeVc

119

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800 lt 275y250 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310times

lt 300y275 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 325y300 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310times

lt 350y325 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 375y350 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 400y375 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B15 Evolution of signal and combinatorial background shapes for 450 lt pT lt 500 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 275y250 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 300y275 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310times

lt 325y300 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 350y325 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 375y350 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300 lt 400y375 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B16 Evolution of signal and combinatorial background shapes for 500 lt pT lt 550 GeVc

120 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400 lt 275y250 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 300y275 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 325y300 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 350y325 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800

lt 375y350 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150

200

250

lt 400y375 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B17 Evolution of signal and combinatorial background shapes for 550 lt pT lt 600 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

lt 275y250 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 300y275 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12310times

lt 325y300 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1310times

lt 350y325 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 375y350 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150 lt 400y375 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B18 Evolution of signal and combinatorial background shapes for 600 lt pT lt 650 GeVc

121

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

lt 275y250 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800

lt 300y275 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800 lt 325y300 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600 lt 350y325 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 375y350 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

80

100

120

140

lt 400y375 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B19 Evolution of signal and combinatorial background shapes for 650 lt pT lt 700 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400 lt 275y250 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 300y275 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 325y300 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 375y350 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150 lt 400y375 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B20 Evolution of signal and combinatorial background shapes for 700 lt pT lt 800 GeVc

122 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 300y275 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 325y300 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800 lt 350y325 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 375y350 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150

200

lt 400y375 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B21 Evolution of signal and combinatorial background shapes for 800 lt pT lt 1000 GeVc

Appendix C

Hadronic-Cocktail fits mdash figures

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C1 Hadronic cocktail fits for 000 lt pT lt 020 GeVc

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 350y325 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 040 GeVT

p020 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 375y350 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 040 GeVT

p020 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 400y375 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 040 GeVT

p020 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C2 Hadronic cocktail fits for 020 lt pT lt 040 GeVc

124 Appendix C Hadronic-Cocktail fits mdash figures

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 350y325 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 400y375 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C3 Hadronic cocktail fits for 040 lt pT lt 060 GeVc

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

12

14

310times

lt 350y325 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 080 GeVT

p060 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 375y350 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 080 GeVT

p060 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

25

310times

lt 400y375 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 080 GeVT

p060 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C4 Hadronic cocktail fits for 060 lt pT lt 080 GeVc

125

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 325y300 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

25

310times

lt 350y325 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

50

310times

lt 375y350 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 400y375 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 375 lt y lt 400

Figure C5 Hadronic cocktail fits for 080 lt pT lt 100 GeVc

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

12

14

310times

lt 325y300 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 350y325 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 375y350 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 400y375 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 375 lt y lt 400

Figure C6 Hadronic cocktail fits for 100 lt pT lt 120 GeVc

126 Appendix C Hadronic-Cocktail fits mdash figures

Not available fit in250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

12

310times

lt 300y275 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 325y300 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

50

310times

lt 350y325 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

50

310times

lt 375y350 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 400y375 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 375 lt y lt 400

Figure C7 Hadronic cocktail fits for 120 lt pT lt 160 GeVc

Not available fit in250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 300y275 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 325y300 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 350y325 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30310times

lt 375y350 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

310times

lt 400y375 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 375 lt y lt 400

Figure C8 Hadronic cocktail fits for 160 lt pT lt 200 GeVc

127

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 275y250 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 300y275 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

310times

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 350y325 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 375y350 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 400y375 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C9 Hadronic cocktail fits for 200 lt pT lt 240 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 275y250 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 300y275 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

5

310times

lt 400y375 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C10 Hadronic cocktail fits for 240 lt pT lt 280 GeVc

128 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

310times

lt 275y250 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 300y275 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 325y300 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

5

310times

lt 350y325 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 375y350 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

310times

lt 400y375 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C11 Hadronic cocktail fits for 280 lt pT lt 320 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 275y250 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 300y275 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 325y300 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

310times

lt 350y325 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 375y350 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 400y375 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C12 Hadronic cocktail fits for 320 lt pT lt 360 GeVc

129

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 275y250 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 300y275 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 325y300 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp lt 325y300 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 350y325 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 375y350 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

310times

lt 400y375 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C13 Hadronic cocktail fits for 360 lt pT lt 400 GeVc

130 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 300y275 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp lt 300y275 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times lt 325y300 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times lt 350y325 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

12

310times

lt 375y350 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

800

lt 400y375 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C14 Hadronic cocktail fits for 400 lt pT lt 450 GeVc

131

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

800

lt 275y250 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

12

14310times lt 300y275 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

310times

lt 325y300 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1310times

lt 350y325 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 375y350 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

500

lt 400y375 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C15 Hadronic cocktail fits for 450 lt pT lt 500 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 275y250 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

800

lt 300y275 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 325y300 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 350y325 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 375y350 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 400y375 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C16 Hadronic cocktail fits for 500 lt pT lt 550 GeVc

132 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 275y250 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 300y275 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

500

lt 325y300 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 350y325 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 375y350 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 400y375 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C17 Hadronic cocktail fits for 550 lt pT lt 600 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300 lt 275y250 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 300y275 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 325y300 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 350y325 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 375y350 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 400y375 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C18 Hadronic cocktail fits for 600 lt pT lt 650 GeVc

133

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200 lt 275y250 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 300y275 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 325y300 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 350y325 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 375y350 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

20

40

60

80

100

lt 400y375 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C19 Hadronic cocktail fits for 650 lt pT lt 700 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 275y250 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 300y275 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 325y300 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 375y350 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 400y375 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C20 Hadronic cocktail fits for 700 lt pT lt 800 GeVc

134 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 300y275 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 325y300 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 350y325 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 375y350 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375Not available fit in

375 lt y lt 400

Figure C21 Hadronic cocktail fits for 800 lt pT lt 1000 GeVc

Bibliography

[1] Michael E Peskin and Daniel V Schroeder An Introduction to Quantum FieldTheory Addison-Wesley 3 edition 1951 (Cited pages 1 et 7)

[2] C A Baker D D Doyle P Geltenbort and others Improved Experimental Limiton the Electric Dipole Moment of the Neutron Phys Rev Lett 97(13)131801September 2006 [link] (Cited page 4)

[3] SM Barr A review of CP violation in atoms International Journal of ModernPhysics A 08(02)209ndash236 January 1993 [link] (Cited page 4)

[4] C Patrignani K Agashe G Aielli and others Review of Particle PhysicsChinPhys C40100001 October 2016 [link] (Cited pages 4 5 7 54 56 58et 105)

[5] E Eichten K Gottfried T Kinoshita and others Charmonium The model PhysRev D 17(11)3090ndash3117 June 1978 [link] (Cited page 6)

[6] Gerardrsquot Hooft Symmetry Breaking Through Bell-Jackiw Anomalies PhysRevLett378ndash11 1976 (Cited page 10)

[7] S P Klevansky The Nambu-Jona-Lasinio model of quantum chromodynamics RevMod Phys 64649ndash708 1992 (Cited pages 10 et 12)

[8] P Costa C A de Sousa M C Ruivo and others The QCD critical end pointin the SU(3) NambundashJona-Lasinio model Physics Letters B 647(5)431ndash435 April2007 [link] (Cited page 10)

[9] J Stachel and G R Young Relativistic Heavy ION Physics at CERN and BNLAnnu Rev Nucl Part Sci 42(1)537ndash597 December 1992 [link] (Cited page 13)

[10] H R Schmidt and J Schukraft The physics of ultra-relativistic heavy-ion collisionsJ Phys G Nucl Part Phys 19(11)1705 1993 [link] (Cited page 13)

[11] RHIC Physics of the Relativistic Heavy Ion Collider 2017 [httpswwwbnlgovrhicphysicsasp] (Cited page 13)

[12] CERN Heavy ions and quark-gluon plasma [httpshomecernaboutphysicsheavy-ions-and-quark-gluon-plasma] (Cited page 13)

[13] ALICE Collaboration φ-meson production at forward rapidity in p-Pb collisionsat radicsNN = 502 TeV and in pp collisions at

radics = 276 TeV Physics Letters B

768203ndash217 May 2017 [link] (Cited pages 14 15 et 26)

[14] Michael L Miller Klaus Reygers Stephen J Sanders and others Glauber Model-ing in High-Energy Nuclear Collisions Annu Rev Nucl Part Sci 57(1)205ndash243October 2007 [link] (Cited page 14)

Remerciements

Je tiens tout drsquoabord agrave remercier lrsquoIPNL sous la direction de Guy Chanfray ainsi quele groupe ALICE de Lyon sous la direction de Brigitte Cheynis pour mrsquoavoir accueillipendant ces trois anneacutees Je tiens aussi agrave remercier le CNRS pour mrsquoavoir permis defaire cette thegravese gracircce agrave leur financement ainsi que le LAVEX LIO (Lyon Institute ofOrigins) de lrsquouniversiteacute de Lyon pour le serveur de calcul du groupe theacuteorie que jrsquoai eulrsquoopportuniteacute drsquoutiliser

Je voudrais remercier Barbara Erazmus qui a bien voulu ecirctre la preacutesidente de monjury de thegravese Roberta Arnaldi et Philippe Crochet pour avoir eacuteteacute mes rapporteurs quigracircce agrave leurs commentaires ont permis drsquoameacuteliorer la qualiteacute de ce manuscrit Merciaussi agrave Alberto Baldisseri et Hubert Hansen qui ont bien voulu ecirctre examinateurs decette thegravese ce qui a contribueacutee agrave lrsquoameacutelioration du document Je voudrais aussi vousremercier drsquoavoir fait le trajet sur Lyon pour avoir assisteacute agrave ma soutenance

Le groupe ALICE de Lyon mrsquoa permis de reacutealiser cette thegravese dans une bonne ambianceJe remercie Brigitte Cheynis ma directrice de thegravese avec qui jrsquoai pu avoir de nombreusesdiscussions que ce sois sur le VZERO pour ma tacircche de service au sein de la collaborationALICE sur des aspects scientifiques de mon analyse ou tous simplement sur lrsquoactualiteacuteainsi que pour les nombreuses corrections orthographiques que ce sois en anglais ou enfranccedilais qursquoelle a apporteacutees agrave mon travail Je tiens aussi agrave remercier Antonio mon co-encadrant de thegravese qui mrsquoa appris la ponctualiteacute italienne avec qui jrsquoai beaucoup apprissur lrsquoanalyse de donneacutees de ma thegravese et avec qui jrsquoai eu de nombreux eacutechangesdiscussionsque se sois scientifiques ou non Je voudrais aussi remercier Cvetan pour toutes lesdiscussions que jrsquoai pu avoir que ce sois sur le VZERO en lien avec ma tacircche de service ousur la physique hadronique et lrsquoexpeacuterience ALICE Ces discussions mrsquoont permis drsquoeacutelargirma vision du domaine Merci aussi agrave Laurent Ducroux pour les eacutechanges en lien aveclrsquoenseignement ainsi que les conseils apregraves mes diffeacuterentes preacutesentations au laboratoireMerci aussi agrave Raphaeumll pour les divers eacutechanges ainsi que sur lrsquoaide apporteacute durant lapreacuteparation de lrsquooral et agrave Massimiliano pour ces quelques mois au laboratoire en tantque nouveau post-doc du groupe ougrave tes conseils et points releveacutes durant ma preacuteparationdrsquooral ont eacuteteacute utile En plus des permanents et post-doc le groupe agrave accueilli des stagiairesdurant ma preacutesence dans le groupe et jrsquoaimerai les remercier pour la bonne humeur etambiance qursquoils sont apporteacutes tous particuliegraverement ceux qui ont cocirctoyeacute mon bureau quece sois pour deux ou six mois merci agrave Thibault Pierre Demongodin Samuel et AlexandreThyvollet ainsi que Pierre-Etienne et Satya pour leur bonne humeur et leur motivationpour participer au tournoi de volley de lrsquoAPPN

Je souhaiterais aussi remercier Hubert et Alexandre Biguet pour leur eacutechanges sur laQCD et la physique hadronique theacuteorique que jrsquoai pu avoir

Je souhaiterai aussi remercier les membres de lrsquoobservatoire des sciences de lrsquouniversqui mrsquoont permis de reacutealiser une tacircche drsquoenseignement pendant deux ans de ma thegravese

vi

Merci agrave Jean-Philippe Perrillat Jean-Franccedilois Gonzalez et Laurent Ducroux pour mrsquoavoirpris dans leur eacutequipe drsquoenseignement cela a eacuteteacute une expeacuterience tregraves enrichissante

I would like to thank all the ALICE collaboration that allowed me to do this thesisand especially I thank all the collaborators who contributed at the lmmumu PAG inparticular Alessandro Di Falco and Ester Casula from the INFN of Cagliari for theirhelp and advice given during the thesis Satoshi Yano from the Hiroshima university forhis contribution of the pp at 13 TeV In addition to the PAG collaborator I would liketo thanks all the DQ people and in particular Diego Laurent Aphecetch and PhilippePillot for their help in the evaluation of the muon arms systematics Martino for all theenriching exchanges on the operation of the ALICE trigger system and the luminosityEvgeny for his response concerning the physics selection and David for the response onthe multiplicity evaluation I would like to thanks Andreas Elena and Marie qualityassurance coordinator with whom I was in contact for my service task for their kindnessand efficiency during the two and a half years or I participated in the QA as well as fortheir understanding on the delays

Cette thegravese mrsquoa permis de mrsquoimmerger dans la communauteacute franccedilaise de la physiquehadronique notamment gracircce aux rencontre QGP France et je voudrais remerciertoutes les personnes avec qui jrsquoai pu avoir de bonnes discussions lors de ces rencontresnotamment les doctorants et post-doc que jrsquoai pu rencontrer Antoine Astrid AudreyBenjamin Emilie Gabriel Gabriele Jana Julien Lucile Maxime Michael et MohamadCette thegravese mrsquoa permis aussi de faire des rencontres enrichissantes durant les diverseseacutecoles que jrsquoai reacutealiseacutes et je souhaiterai remercier les doctorants qui y ont participeacute pourles bons moments passeacutes dans ces diverses eacutecoles

Bien sucircr je souhaite aussi remercier les doctorants qui ont cocirctoyeacute lrsquoIPNL durant cestrois anneacutees notamment Alexandre Biguet Anne-Laure Bertrand Ceacutecile Elvire Eme-line Franccedilois Guillaume Garilot Guillaume Victor Jean-Baptiste Joffrey Lola NicolasBaillot Nicolas Deutschmann Nicolas Galy Pierre Becker Reacutemi et Solegravene En plus desdoctorants que jrsquoai cocirctoyeacutes je souhaiterai aussi remercier Alain Cleacutement David GeoffreyHubert Martin Sylvie et Yoan pour les nombreuses pauses cafeacute pris ensemble durant cestrois anneacutees ainsi qursquoAntoine pour avoir accepteacute drsquoecirctre mon parrain pour ma thegravese

Merci aussi agrave Aureacutelie Camille Eacuteloiumlse Florian et Laurine pour tous les bons momentsque ce sois les midis en soireacutee durant des films ou des sessions jeux Merci aussi agrave Clairepour toutes ces discussions et soutiens mutuel pour nos thegraveses malgreacute le deacutecalage entrela France et le Breacutesil

Enfin jrsquoaimerais remercier ma famille pour leur soutiens durant toute ma formationuniversitaire ainsi que durant ma thegravese Je suis sucircr que mes grands-parents paternel auraieacuteteacute tregraves fiegravere de me voir arriver jusqursquoagrave ce diplocircme eux qui eacutetaient inquiets de savoir sijrsquoy arriverai ainsi que Christian et Thierry mes oncles auraient eacuteteacute fiegravere et auraient aimeacuteme voir agrave ce niveau

Reacutesumeacute

Ce manuscrit sur mon travail de thegravese commence par un premier chapitre sur les motiva-tions physiques du sujet eacutetudieacute tant sur le plan theacuteorique qursquoexpeacuterimental Dans le deux-iegraveme chapitre je traiterai du collisionneur de particules ayant produit les collisions danslrsquoexpeacuterience ALICE utiliseacutees durant lrsquoanalyse preacutesenteacutee dans ce manuscrit La secondepartie de ce chapitre est justement deacutedieacutee agrave lrsquoappareillage ALICE Le troisiegraveme chapitreporte sur la caracteacuterisation du jeu de donneacutees que jrsquoai exploiteacute ainsi que sur lrsquoeacutevaluationde la luminositeacute inteacutegreacutee correspondant agrave cet eacutechantillon Le quatriegraveme chapitre quant agravelui porte sur les simulations Monte-Carlo qui ont du ecirctre faites pour mener agrave bien cetteanalyse Le cinquiegraveme chapitre sur la meacutethodologie utiliseacutee pour extraire de nos don-neacutees les signaux drsquointeacuterecirct Dans lrsquoavant-dernier chapitre le sixiegraveme nous traiterons delrsquoeacutevaluation des quatre sources de systeacutematiques qui impactent notre analyse Le dernierchapitre traitera des reacutesultats que nous avons pu obtenir en termes de sections efficacesde production de meacutesons neutres leacutegers

Cadre Physique (chapitre 1)Le cadre theacuteorique englobant le travail preacutesenteacute dans ce document est la chromodynamiquequantique deacutecrivant lrsquointeraction forte lrsquoune des quatre interactions fondamentales quenous connaissons agrave lrsquoheure actuelle agissant sur les quarks et les gluons par eacutechangede gluons On verra que cette theacuteorie peut srsquoexprimer matheacutematiquement en termes dedensiteacute Lagrangienne De ce Lagrangien peut ecirctre extraite une symeacutetrie particuliegraverementinteacuteressante pour lrsquoeacutetude des meacutesons leacutegers neutres la symeacutetrie chirale qui sera traiteacutee endeacutetails dans ce chapitre introductif De la chromodynamique quantique peut ecirctre extraitun diagramme thermodynamique de la matiegravere hadronique dans lequel deux principalesphases sont visibles la phase ougrave la matiegravere hadronique se condense sous forme de hadronset la phase partonique ougrave est creacuteeacute un plasma de quarks et de gluons (QGP)

Expeacuterimentalement ce diagramme de phases peut ecirctre eacutetudieacute gracircce agrave des acceacuteleacuterateursde particules permettant de faire des collisions cible fixe etou en mode collisionneurDans la seconde partie de ce chapitre je commencerai par introduire quelques variablescineacutematiques drsquointeacuterecirct pour le domaine ainsi que deux concepts geacuteomeacutetriques qui sont lacentraliteacute de la collision deacutetermineacutee par la distance qui seacutepare les centres des deux noyauxet le plan de reacuteaction de la collision Une collision entre deux noyaux comporte plusieurseacutetapes chronologiques notamment la phase de QGP suivie par deux phases hadroniquesdomineacutees respectivement par des collisions ineacutelastiques et eacutelastiques cela engendre desproductions de particules tregraves diverses Dans la suite du chapitre seront parcourus tousles types de sondes inteacuteressantes pour lrsquoeacutetude des collisions drsquoions lourds jrsquoen profiteraipour faire un petit eacutetat de lrsquoart des mesures faites dans les diffeacuterentes voies drsquoobservationBien sucircr les reacutesultats montreacutes le sont seulement agrave titre drsquoexemple et pas de maniegravereexhaustive

La derniegravere section sur les reacutesultats expeacuterimentaux est focaliseacutee sur la productionde dimuons de basses masses dans ALICE qui fait lrsquoobjet de lrsquoeacutetude rapporteacutee dans ce

viii

manuscrit Dans les preacuteceacutedentes eacutetudes lrsquoaccent eacutetait mis sur le meacuteson φ qui est agrave lrsquooriginedu signal le plus facilement observable dans la reacutegion des basses masses Dans notre caslrsquoeacutetude a eacuteteacute porteacutee sur les meacutesons η ρω et φ car la statistique disponible dans le lotde donneacutees eacutetudieacute est suffisante pour extraire les signaux correspondants

LHC et ALICE (chapitre 2)La premiegravere partie du chapitre 2 sera consacreacutee au LHC notamment au complexedrsquoacceacuteleacuterateurs permettant drsquoinjecter au sein du LHC des noyaux ou des protons Onen profitera pour eacutevoquer les sceacutenarios futurs agrave relativement court terme pour le LHC etpour finir cette courte partie les programmes drsquoions lourds au CERN et plus geacuteneacuteralementdans le monde

La seconde partie du chapitre est deacutedieacutee au deacutetecteur ALICE Cette partie peut ecirctregrossiegraverement coupeacutee en deux parties la premiegravere deacutedieacutee au deacutetecteur actuel et son fonc-tionnement la seconde au programme drsquoameacutelioration qui doit deacutebuter agrave la fin du Run 2du LHC

Luminositeacute et Jeu de Donneacutees (chapitre 3)Dans ce chapitre deux points seront eacutevoqueacutes Le premier porte sur les conditions expeacuteri-mentales pour les donneacutees proton-proton agrave 13 TeV prises en 2016 utiliseacutees dans lrsquoanalysedeacutecrite dans ce manuscrit Le second porte sur lrsquoeacutevaluation de la luminositeacute inteacutegreacuteeCette mesure nous permet drsquoeacutevaluer des sections efficaces de production agrave partir des tauxde production connaissant la section efficace associeacutee agrave la condition de deacuteclenchement debiais minimal de lrsquoexpeacuterience et le nombre drsquoeacuteveacutenements de biais minimal eacutequivalent aujeu de donneacutees consideacutereacute dans lrsquoanalyse Ce chapitre ne traitera pas de lrsquoeacutevaluation decette section efficace de biais minimal qui fait lrsquoobjet drsquoune eacutetude agrave part entiegravere non dis-cuteacute dans ce manuscrit et qui sert agrave toutes les analyses Cette section traitera en deacutetailsde la proceacutedure permettant drsquoavoir le facteur de conversion entre le nombre drsquoeacuteveacutenementsanalyseacutes et le nombre eacutequivalent drsquoeacuteveacutenements de biais minimal

Simulations Monte-Carlo (chapitre 4)Ce chapitre est structureacute en deux parties la premiegravere se focalisant sur les meacutesons neutresleacutegers et la deuxiegraveme sur les simulations des processus de charme et beauteacute ouverte

Dans la partie sur les meacutesons on commencera par donner quelques geacuteneacuteraliteacutes surces particules ainsi que sur le geacuteneacuterateur employeacute dans les simulations Puis on traiteradeux cas drsquointeacuterecirct Le premier cas concerne les processus faisant intervenir trois particulesdans lrsquoeacutetat final de la deacutesinteacutegration (deacutesinteacutegration Dalitz) en mettant lrsquoaccent sur leurfacteur de forme Le second cas quandt agrave lui correspond aux deacutesinteacutegrations agrave deuxcorps dans les canaux dileptoniques et plus particuliegraverement dans celui dimuonique

La seconde partie du chapitre est consacreacutee aux dimuons venant des deacutesinteacutegrationsdes saveurs lourdes ouvertes Un dimuon venant des saveurs lourdes ouvertes est deacutefini

ix

comme deux muons produits durant les chaicircnes de deacutesinteacutegration drsquoune paire quark anti-quark charmeacutes ou beaux On verra dans cette section qursquoun impact visible sur le spectreen masse deacutecoule de la distribution cineacutematique initiale du quark beau ou charmeacute gracircceaux comparaisons que nous avons faites avec des simulations utilisant les distributionscineacutematiques de PYTHIA6 et de FONLL Le dernier point eacutevoqueacute dans ce chapitre concernela longueur de chaicircne de deacutesinteacutegration des hadrons charmeacutes et beaux car nous sommesinteacuteresseacutes agrave reproduire les dimuons venant des paires de charme ou de beauteacute qui sontcorreacuteleacutes Une hypothegravese que nous pouvons faire est que plus une chaicircne de deacutesinteacutegrationest longue plus la correacutelation reacutesultante de la paire est amoindrie On montrera que leprofil de longueur de chaicircne de deacutesinteacutegration possegravede une structure relativement complexeet qursquoil y a un impact sur le spectre en masse en ne consideacuterant qursquoun certain intervallede longueur de deacutesinteacutegration

Extraction du Signal (chapitre 5)Dans ce chapitre deux points seront eacutevoqueacutes le premier sera lrsquoeacutevaluation et la soustractiondu bruit combinatoire le second portera sur la proceacutedure utiliseacutee pour extraire le signal

La composante de bruit combinatoire dans les dimuons de signes opposeacutes aussi appeleacutebruit non-correacuteleacute provient de la meacutethode de construction des dimuons Cette meacutethodeneacutecessite la creacuteation de toutes les paires de dimuons possibles dans un eacuteveacutenement Poureacutevaluer cette composante nous employons la technique du mixage drsquoeacuteveacutenements crsquoest-agrave-dire que nous creacuteons agrave lrsquoaide des donneacutees un lot de dimuons qui par construction serontnon-correacuteleacutes en formant chaque dimuon par combinaison drsquoun muon drsquoun eacuteveacutenement avecun muon drsquoun autre eacuteveacutenement La distribution ainsi obtenue est normaliseacutee agrave partir desdistributions de dimuons de mecircmes signes Cette proceacutedure agrave eacuteteacute valideacutee agrave lrsquoaide desimulations Monte-Carlo Une fois la soustraction du bruit faite pour chaque intervalleen pT et y consideacutereacute dans notre analyse nous pouvons passer agrave lrsquoextraction du signal

Pour extraire le signal drsquointeacuterecirct de notre spectre de dimuons correacuteleacutes nous utilisonsune proceacutedure drsquoajustement par minimisation du χ2 Cette proceacutedure est baseacutee sur unefonction servant agrave lrsquoajustement qui est composeacutee des distributions en masse des pro-cessus hadroniques composant notre cocktail hadronique Nous verrons notamment parquel moyen nous arrivons agrave reacuteduire le nombre de degreacutes de liberteacute de notre fonction enasservissant certaines composantes agrave drsquoautres Une grande partie de ce point est consacreacuteeau traitement du continuum correacuteleacute et aux meacutethodes permettant de deacutecrire la forme dela fonction modeacutelisant le continuum correacuteleacute

Eacutevaluation des Systeacutematiques (chapitre 6)Ce chapitre est diviseacute en quatre parties une pour chaque contribution agrave la systeacutematiquede notre analyse

La premiegravere partie traitera de la systeacutematique sur lrsquoextraction du signal et notammentsur lrsquoeacutevaluation de la systeacutematique sur tous les choix que nous avons faits pour reacutealisernotre ajustement Pour cela un ou plusieurs tests sont faits en modifiant agrave chaque foisun seul paramegravetre par rapport agrave notre ajustement de reacutefeacuterence Une fois tous les tests

x

reacutealiseacutes pour un intervalle en pT-y consideacutereacute dans cette analyse on eacutevalue par la meacutethodede deacuteviation standard lrsquoerreur systeacutematique qui en reacutesulte

Les autres parties traiteront de la systeacutematique lieacutee agrave lrsquoestimation du produit delrsquoacceptante geacuteomeacutetrique et de lrsquoefficaciteacute de reconstruction notamment le choix de lrsquoinputcineacutematique pour les simulations Monte-Carlo lrsquoincertitude sur lrsquoefficaciteacute du systegraveme dedeacuteclenchement et sur lrsquoefficaciteacute du systegraveme de trajectographie

Reacutesultats (chapitre 7)Dans ce dernier chapitre avant de parler des reacutesultats nous discuterons la correction dusignal extrait des distributions de masse invariante reconstruit pour lrsquoestimation de lasection efficace de production Nous passerons ensuite aux reacutesultats en preacutesentant et endiscutant la deacutependance en pT et y de la section efficace de production des meacutesons ηρω et φ Les reacutesultats obtenus dans cette analyse seront compareacutes aux preacutedictions desmodegraveles PYTHIA et PHOJET et aux reacutesultats disponibles dans ALICE agrave drsquoautres eacutenergies

Table of contents xi

Table of contents

1 Physics Motivations 111 Theoretical Baseline 1

111 Quantum ChromoDynamics (QCD) 3112 Chiral Symmetry 6113 Hadronic Matter mdash Quark-Gluon Plasma (QGP) 11

12 Heavy-Ion Physics Experimental Program 12121 Relevant Kinematic Variables 13122 Collision Geometry 14123 Evolution of a Heavy-Ion Collision 15124 Experimental Observables of the QGP 16125 Proton-Proton Collisions 22

13 Low-Mass Dimuon Measurements in ALICE 23

2 ALICE at the CERN LHC 2921 The Large Hadron Collider 29

211 The CERN accelerator complex 29212 The LHC schedule 30213 The Experimental Heavy-Ion Program 32

22 A Large Ion Collider Experiment (ALICE) 33221 The Central Barrel 34222 The Forward Detectors 36223 The Muon Spectrometer 38224 The ALICE software framework 40225 The ALICE Upgrade 41

3 Data Sample Selection and Integrated Luminosity Evaluation 4531 Data Sample Event and Track Selection 4532 Integrated Luminosity Evaluation 46

321 F inorm Calculation 47

322 The MB Trigger Cross Section 50323 Lint Evaluation 51

4 Monte Carlo Simulations 5341 Light-Meson Decays 53

411 Kinematical Distributions 54412 Dalitz Decays 54413 Two-Body Decays 57

42 Dimuons from Open Heavy-Flavor Decays 60421 PYTHIAndash FONLL Comparison 61422 Decay Chain Length in the Open Heavy-Flavor Processes 62

xii Table of contents

5 Signal Extraction 6551 Combinatorial Background Evaluation and Subtraction 65

511 The Event Mixing Technique 66512 Monte Carlo Validation of the Event Mixing Technique 67513 The Combinatorial Background Estimation 68

52 Invariant Mass Fit Procedure 70521 Specific Constraints on the Hadronic Cocktail Components 71522 Correlated Continuum Treatment 72523 A Few Examples of Hadronic Cocktail Fits 76

6 Systematics Evaluation 7961 Systematics on the Signal Extraction 80

611 Relative Branching Ratio of two-body and Dalitz Decays for the ηand ω Mesons 80

612 σηprimeσφ Cross-Section Ratio 80613 σρσω Cross-Section Ratio 81614 Upper limit of the fit 81615 The correlated continuum shape 81616 Systematic Uncertainty Computation 82

62 Systematics from the MC input 8263 Systematics on Trigger Efficiency 83

631 Evaluation of the Trigger Response Function 83632 Results 84

64 Systematics on Tracking Efficiency 85641 Preliminary Check 85642 Tracking Efficiency Evaluation 86643 MC parametrization 88644 Results 89

65 Summary of Systematic Uncertainty 89

7 Light Neutral Meson Production 9171 Estimation of the Number of Generated Mesons 91

711 The Two-Body Decay Case 91712 The Dalitz Decay Case 92

72 Cross-Section Production for Light Neutral Mesons 93721 Double-Differential η Meson Production 93722 ρω Meson Production 94723 Double-Differential φ Meson Production 98

Conclusions 105

A List of Runs 107

B Raw-Background Comparison mdash figures 111

C Hadronic-Cocktail fits mdash figures 123

Table of contents xiii

Bibliography 135

Chapter 1

Physics Motivations

Summary11 Theoretical Baseline 1

111 Quantum ChromoDynamics (QCD) 3112 Chiral Symmetry 6113 Hadronic Matter mdash Quark-Gluon Plasma (QGP) 11

12 Heavy-Ion Physics Experimental Program 12121 Relevant Kinematic Variables 13122 Collision Geometry 14123 Evolution of a Heavy-Ion Collision 15124 Experimental Observables of the QGP 16125 Proton-Proton Collisions 22

13 Low-Mass Dimuon Measurements in ALICE 23

11 Theoretical BaselineThe theoretical framework underlying the subject of the present thesis is the StandardModel of particle physics (SM) The SM gathers the theories describing the electromag-netic weak and strong interactions as well as Higgs sector providing at the same timea classification of all the subatomic particles known in terms of matter constituents andgauge bosons see figure 11 It was developed throughout the latter half of the 20th cen-tury the current formulation having been finalized in the mid-1970s upon experimentalconfirmation of the existence of quarks Since then discoveries of the Wplusmn and Z0 bosons(1983) the top quark (1995) the tau neutrino (2000) and the Higgs boson (2012) havegiven further credence to the Standard Model [1]

Each elementary interaction in the SM is characterized by an interaction range anda set of gauge bosons carrying the interaction charge It should be noted that the SMdescribes the weak and electromagnetic interactions as two different aspects of a singleelectroweak interaction

bull The weak interaction has a very small range of the order of 10minus18 m and is medi-ated by the Z0W+ and Wminus bosons This interaction affects all known elementaryfermions

2 Chapter 1 Physics Motivations

bull The electromagnetic interaction is characterized by an infinite range and affectsany particle having a non-zero electric charge The associated gauge boson is thephoton

bull The strong interaction acts at small distances having a range of the order of 10minus15 mat this range the strong interaction dominates over the other elementary interac-tions The strong interaction is mediated by the exchange of massless gauge bosonscalled gluons that interact with quarks anti-quarks and other gluons via a chargecalled color charge The theoretical framework for the strong interaction is givenby the theory of Quantum Chromodynamics described in more details in the nextsection

12e neutrino

νe

minus1

12

510999 keV

electron

e

RGB23

12

22+06minus04 MeV

up

uRGB

minus13

12

47+05minus04 MeV

down

d

12micro neutrino

νmicro

minus1

12

105658 MeV

muon

micro

RGB23

12

127 plusmn 003 GeV

charm

cRGB

minus13

12

96+8minus4 MeV

strange

s

12τ neutrino

ντ

minus1

12

177686 plusmn 016 MeV

tau

τ

RGB23

12

160+5minus4 GeV

top

tRGB

minus13

12

418+004minus003 GeV

bottom

b

plusmn1

1

80385 plusmn 0015 GeV

Wplusmn1

911876 plusmn 00021 GeV

Z

1photon

γ

color

1gluon

g0

12509 plusmn 024 GeV

Higgs

Hst

rong

inte

ract

ion

elec

trom

agne

ticin

tera

ctio

n

weak

inte

ract

ion

6qu

arks

(+6

anti-

quar

ks)

6le

pton

s(+

6an

ti-le

pton

s)

12 fermions(+12 anti-fermions)

13 bosons

Matter Constituents Gauge BosonsGoldstone

bosons

1st 2nd 3rd generation

1

Figure 11 Standard Model of particle physics and the different families of matter

11 Theoretical Baseline 3

111 Quantum ChromoDynamics (QCD)The Quantum ChromoDynamics (QCD) is the theory describing the hadronic physicsphenomena in the framework of the SM For this reason QCD is needed to correctlydescribe and interpret the observations in experiments involving high-energy hadronicinteractions like ALICE at the LHC

The color charge of the QCD can have three different values (red green and blue) aswell as the corresponding anti-colors This determines a part of the mathematical struc-ture of QCD based on the special unitary group of degree 3 mdash the Lie group SU(Nc=3)cThe complete mathematical structure of QCD is based on the Lorentz group L = SO(1 3)for the space-time transformations (gluons are in the vector representation and quarksin the spinor one) a gauge symmetry SU(Nc = 3)c an approximate light flavor symme-try SU(Nf = 3)f (this symmetry is not relevant even approximately for the remaining3 heavy flavors) The introduction of a three-color charge allowed at the beginning ofthe development of the QCD for the reconciliation of the observation of the spin-3

2 ∆++

baryon composed of three up quarks in the same spin state with the Pauli exclusionprinciple

The QCD Lagrangian LQCD

In the Quantum Field Theory formalism of particle physics any theory can be expressedin terms of a Lagrangian The mathematical expression of the Lagrangian density ofQCD1 is

LQCD =flavorssumf

qc1f (ipartmicroγmicroδc1c2 minusmfδc1c2) qc2

f

+flavorssumf

qc1f gsA

amicrotac1c2γ

microqc2f minus

14G

microνa G

amicroν + LCP

(11)

(Besides the explicit flavor summation each index when repeated twice indicates asummation on this index) In equation (11) micro ν are Minkowski indexes ranging from 0to 3 the qcf spinor represents the quark field of flavor f and color c (the Dirac index ofquark fields and γ-matrices are not written explicitly for convenience) mf is the massof a quark of flavor f gs is linked to the coupling constant of the theory αs = g2

s4π(after quantification and renormalization αs becomes a running coupling constant alsoquantification requires the introduction of ghost fields) the gluon fields Aamicro are Lorentzvectors Gmicroν

a is the gluon strength tensor and the ta matrices (generators of SU(Nc=3)c)are defined after the Gell-Mann matrices ta = λa2

The first term of LQCD

Lfree q =flavorssumf

qc1f (ipartmicroγmicroδc1c2 minusmfδc1c2) qc2

f = q (ipart minus mf ) q (12)

is a free Lagrangian representing the propagation of free quarks m representing thediagonal quark mass matrix

1 By language abuse the QCD Lagrangian density is simply named QCD Lagrangian

4 Chapter 1 Physics Motivations

The second term

Lint =flavorssumf

qc1f gsA

amicrotac1c2γ

microqc2f = gsqAq (13)

encodes the minimal (or Yukawa) coupling describing the interaction of the quark fieldswith the gluons

The third term of LQCD involvesGamicroν the gluon strength tensor which can be expressed

asGamicroν = partmicroA

aν minus partνAamicro + gsf

abcAbmicroAcν (14)

The fabc coefficients are the structure constants of SU(3) The first part of the tensor inequation (14) partmicroAaν minus partνA

amicro describes the gluon kinematics in analogy to the kinematics

description of photons in quantum electrodynamics (QED) The last term gsfabcAbmicroA

cν is

specific to QCD and describes the gluon auto-coupling due to the fact the QCD is anon-Abelian theory

The last term in equation (11) LCP is related to a possible violation of the CP-symmetry (due to a breaking of T symmetry and the conservation of the CPT symmetry)in the QCD sector This term is defined as

LCP = θg2s

32π2 GamicroνG

microνa (15)

where G is the dual of GGamicroν = 1

2εmicroναβGαβa (16)

and εmicroναβ is the antisymmetric Levi-Civita pseudo-tensor The θ parameter which wouldtake a non-zero value in case of CP-violation of LQCD can be experimentally accessed bymeasuring the electric dipole momentum of the neutron Its value compatible with zerois currently not explained by the theory [2 3]

The QCD Running Coupling Constant αs

By using the perturbative-QCD (pQCD) and the renormalization group equation [4] it ispossible to extract a running coupling constant αs depending on the momentum transferQ and on a parameter ΛQCD establishing the scale at which the perturbatively-definedcoupling would diverge At first order of perturbation theory αs can be expressed as

αs(Q2) = 12π

(11Nc minus 2Nf ) ln(

Q2

Λ2QCD

) (17)

where Nc is the number of colors (3) Nf is the number of light flavors respecting mq Q

and ΛQCD asymp 200 MeVFigure 12 shows the excellent agreement between available measurements of αs(Q2)

and the pQCD theoretical prediction beyond first order According to the value of thetransfer momentum Q two regimes of QCD can be defined for values of the transfermomentum Q above Q asymp 1 GeV (of the order of the nucleon mass) implying Q ΛQCD(or for distances well below 1 fm corresponding to the nucleon size) QCD is in the regime ofasymptotic freedom for Q 1 GeV QCD behavior is dominated by the color confinementmechanism

11 Theoretical Baseline 5

Figure 12 Summary of measurements of αs as a function of the momentum transfer Q and thepQCD prediction [4]

Asymptotic Freedom

In the large momentum transfer region Q ΛQCD or at small distance the decreasingof the coupling constant αs reflects the fact that the particles interacting over shortdistances 1 fm (the typical size of the nucleon) can be treated asymptotically as quasi-free particles This allows one to use a perturbative approach in performing calculationsbased on series of αs powers Let us notice that asymptotic freedom does not mean thatquarks are not interacting at all in high-energy collisions (the freedom is only asymptotic)Indeed it has been shown that at RHIC energy a strongly interacting QGP (s-QGP) iscreated

Color Confinement

Figure 13 Sketch of twoquark separation

In the small momentum transfer region or large distancethe coupling constant perturbatively diverges The physicalinterpretation for this phenomenon is the color confinementA schematic explanation of this phenomenon is the followingif it was possible to hold two color charges (for example twoquarks) and pull them part the energy density would con-centrate into a flux tube due to the non-Abelian characteris-tics of QCD (differently to QED) The energy would increasewith the separation until it reaches a threshold above whichpair creation is possible Figure 13 sketches this effect known as string breaking This isthe reason why in vacuum it is not possible to observe directly one isolated quark and allof them are found in composite particles named hadrons the color charge of hadrons iszero (hadrons are ldquocolorlessrdquo or ldquowhiterdquo) as the colored flux tube wraps within the hadronitself and can be observed

6 Chapter 1 Physics Motivations

A simple modelisation of the potential V (r) between two quarks is given by the Cornellpotential [5]

V (r) = minusαsr

+ σr (18)

In equation (18) the first term models the asymptotic freedom with a Coulomb potential(this term is dominating at r rarr 0) and the second term (dominating when r rarr infin) iscalled the string potential with the string tension σ sim (260 MeV2)

Hadrons can be classified as

bull mesons composed of one quark and one anti-quark

bull baryons composed of three quarks

bull exotic states like the recently observed tetra-quark etc

112 Chiral SymmetryThe chiral symmetry is one of the two fundamental symmetries of QCD governing low-energy QCD (low-hadronic masses) and the properties of the transition between the par-tonic and the hadronic phases observed in heavy-ion collisions

The chiral symmetry can be conveniently introduced and discussed considering theway Lorentz transformations act on bosons and fermions To start this discussion let usconsider a massless universe To understand the properties of the Lorentz transformationof any quantum state one can decompose it into its fundamental building blocks calledchiral fermions χR (the right chiral fermion) and χL (the left chiral fermion) PhysicallyχR and χL are spinor fields (spin frac12) and the R and L indices denote the helicities ofthe states In a massless universe the helicity is a good quantum number there is noLorentz transformation that can change the ldquoorientationrdquo of the spin hence for any inertialobservers the measured helicity would be the same Since χR and χL are fundamentalstates when Lorentz transformations are considered one can build any spin state bymixing these building blocks mathematically the Lorentz group can then be describedas a SU(2)RotimesSU(2)L group whose fundamental representations2 are χR and χL

Let us now consider a massive fermion state obviously now two observers with differ-ent speed relative to the fermion will measure different projections of the spin along themomentum of the particle the helicity is no more a good quantum number The chiralfermions χR and χL can now transform into one another this mechanism is called thebreaking of the chiral symmetry As anticipated in the introduction of this section thissymmetry is crucial to understand the low-mass sector of QCD since it is dominated byhadronic states composed of almost massless quarks (namely u d s composing the light

2 To see why the SO(13) Lorentz group L can be described by the combination of two SU(2) groupsone has to remember that L contains three rotations (that gives one SU(2) group) and three boosts (thatcan be seen as rotation involving the time direction and an imaginary angle that gives another SU(2)group) Those two algebras are not independent (eg boost and rotation do not commute) but they canbe decoupled into SU(2)RotimesSU(2)L independent algebras

11 Theoretical Baseline 7

neutral meson studied in this thesis) compared to the typical scale of QCD ΛQCD (seetable 11)

u m = 22+06minus04 MeVc2 c m = 127plusmn 003 GeVc2 t m = 160+5

minus4 GeVc2

d m = 47+05minus04 MeVc2 s m = 96+6

minus4 MeVc2 b m = 418+04minus03 GeVc2

Table 11 Quark masses [4]

In the following we will explain with a very simple quark model some observablephenomena linked to the fundamental QCD chiral symmetry the non observation ofdegeneration in mass between the scalar and pseudo-scalar octet as well as the spontaneouschiral symmetry breaking related to the phase transition observed eg in LHC arounda temperature of 170 MeV

a A Lagrangian for a free massless quark

For one chiral quark χR the free Lagrangian is3

Lfree qR = iχdaggerRpart0χR + iχdaggerRminusrarrσ middotminusrarrpart χR (19)

the form of the Lagrangian being dictated by the usual constraints (Lorentz invariancehermiticity conservation laws) but for one quark flavor the state with opposite helicityalso exists in nature for one quark flavor one can write Lfree q = Lfree qR + Lfree qLThis can be conveniently written

Lfree q = qipartq (110)

where q is a Weyl spinor (4 component spinor)

q =[χRχL

] (111)

and the usual notation q = qdaggerγ0 (see chapter 32 of [1])

b Explicit breaking of the chiral symmetry in presence of a mass term

The Lagrangian of a free quark of mass m is

Lfree q = q (ipart minusm) q = L0 + Lm (112)

This Lagrangian contains a mass term which is explicitly written as

Lm = mqq = m(χdaggerRχL + χdaggerLχR

) (113)

The number of R (L) quarks in this system is given by

NRL = χdaggerRχR(χdaggerLχL

) (114)

3 We do not consider Majorana fermions in this manuscript

8 Chapter 1 Physics Motivations

Let us define a transformation belonging to the symmetry group U(1)RotimesU(1)L

χR rarr eiθR χR

χL rarr eiθL χL

Lfree q rarr L0 +m(ei(θLminusθR) χdaggerRχL + ei(θRminusθL) χdaggerLχR

) (115)

this symmetry is broken by the mass term as discuss previously when considering thecase of the boost of a massive fermion the number of R or L quarks is not the samefor all observers However this symmetry restricted to the case of θR = θL equiv θV is notbroken and is associated to the conservation of the fermion number This result in theUV (1) symmetry

q rarr eiθV q lArrrArr[χRχL

]rarr eiθV

[χRχL

] Lfree q rarr Lfree q (116)

The V stands for Vector (it is the conservation of the so-called vector current V micro = qγmicroq)For further convenience we also define UA(1) as the symmetry group with transformationgiven by θR = minusθL equiv θA the A stands for Axial (a transformation in UA(1) is thus givenby q rarr eiθAγ5 q)

c For more than one flavor

Finally let us consider the Lagrangian of a system composed by the two lightest flavorsu and d giving Nf = 2 (but this discussion could also be extended to a system includinga third flavor s light enough compared to ΛQCD)

Lfree light q = iqupartmicroγmicroqu + iqdpartmicroγ

microqd minusmuququ minusmdqdqd (117)

In this case one can introduce for convenience the iso-spinor ψ =(quqd

)

Lfree light q = ψ (ipart minus m0)ψ (118)

= iψpartmicroγmicroψ minus mu +md

2 ψψ minus mu minusmd

2 ψτ3ψ (119)

where m0 is the quark masses matrix τ3 is the iso-spin Pauli matrix (noted τ not toconfuse it with σ3 that acts on spinor index) For convenience let us also use

ψR equiv[quRqdR

]equiv

quR0qdR0

equiv PRψ (120)

wherePR = 1 + γ5

2 (121)

and the same for ψL wherePL = 1minus γ5

2 (122)

11 Theoretical Baseline 9

The symmetry we discussed in paragraph b is extended by adding a mixing ofthe flavor states This is what is usually called in the literature ldquochiral symmetryrdquoSUR(Nf )timesSUL(Nf )

The iso-spinor ψ = ψR + ψL transforms under the chiral symmetry as

ψ rarr eiminusrarrθR middotminusrarrt ψR + ei

minusrarrθL middotminusrarrt ψL (123)

where minusrarrt = ~τ

2 and minusrarrθRminusrarrθL isin (R3)2

As in the one flavor case the kinetic term

Lk = iψLpartmicroγmicroψL + iψRpartmicroγ

microψR (124)

is chiral invariant while the mass term is not However when the mass difference is zero(the so-called exact isospin limit) the SUV (Nf ) symmetry is exact

d The symmetry of the quark sector of QCD mdash the eightfold way

Let us consider only massless quarks (a good approximation for u d and s) giving Nf = 3and the light sector only

LQCD = Lfree light q + Lr (125)

where Lr incorporates the terms appearing in the second line of equation (11) as wellas any term relative to heavy quark Lr transforms trivially or in the same way as aLfree light q For this reason the chiral transformation of LQCD can be studied consideringLfree q only In this massless scenario the largest symmetry group for LQCD can be ex-pressed as G=UR(1)otimesUL(1)otimesSUR(Nf )otimesSUL(Nf ) = UR(Nf )otimesUL(Nf ) A transformationof this group is given by

ψ rarr eiθR t ψR + eiθL t ψL (126)

where t =(1~t

)and θ =

(θ ~θ

) This symmetry would allow one to classify light hadronic

states into double U(Nf = 3) multiplets (one for left-handed and one for right-handed)where scalar and pseudo-scalar members would be invariant under U(Nf = 3) rotationin the flavor space which implies the same mass This is not what is observed Atmost one sees multiplets (approximately) invariant under vector symmetry SUV (Nf = 3)rotation (see paragraph b ) for example the octet of pseudo-scalar mesons π K η andthe decuplet of baryons n p Λ etc

The chiral partner of the cited pseudoscalar meson octet is the scalar octet of the a0κ and σ meson the fact that no degeneracy in mass is observed between the members ofthe pseudoscalar octet and the members of the scalar one is linked to the G symmetrybreaking For convenience one can rewrite G = UR(Nf = 3)timesUL(Nf = 3) as

G = UV (1)otimes UA(1)otimes SUV (3)otimes SUA(3) (127)

where

bull UV (1) is the symmetry already discussed in paragraph b it is the conservation ofthe individual flavor quark number

10 Chapter 1 Physics Motivations

bull UA(1) was also introduced in paragraph b This group should be a symmetry in themassless scenario leading to the observation of mη = mηprime (one should see a nonetinstead of an octet of degenerated pseudoscalar mesons) [6] This is howevernot the case The more generally accepted explanation is that the gluon part Lr

of LQCD generates an explicit breaking of the UA(1) symmetry due to non-zeroquantum fluctuations in the gluon strength tensor sim 〈G2〉

G2 = GmicroνGmicroν (128)

bull SUV (3) this is the observed (approximate) symmetry between the masses of themembers of a multiplet4 This means that the SUV (3) symmetry is good enough toclassify hadronic states this corresponds to ldquothe eightfold wayrdquo

bull SUA(3) this group should be again a symmetry in a massless scenario one wouldthen observe a degeneracy between the scalar and the pseudoscalar meson octetThis is not the case because the chiral symmetry SUV (Nf )otimesSUA(Nf ) is sponta-neously broken (Goldstone mechanism) to SUV (Nf = 3) The π K η are the(almost) massless Goldstone bosons of this mechanism

e Spontaneous breaking of the chiral symmetry and phase transition

The Goldstone mechanism just mentioned when discussing the SUA(3) group can beunderstood in the framework of a quark model the Nambu-Jona-Lasinio model [78] withmassless quarks For two light flavors one has

LNJL = ψ (ipart)ψ +Gs

[(ψψ

)2+(ψiγ5~τψ

)2] (129)

where Gs is a coupling constant for four-quark contact interactions It mimics the shortrange strong interaction as a contact interaction This Lagrangian is chirally invariantsince the interaction term is built from a scalar ψψ and its pseudoscalar counterpart soas to be invariant

If the interaction term is sufficiently large (GsΛQCD2 sim 1) quarks can condense

(〈ψψ〉 6= 0) and equation (129) can be rewritten as

LNJL ψ(ipart + 2Gs〈ψψ〉

)ψ + middot middot middot (130)

The quantity mD equiv minus2Gs〈ψψ〉 acts exactly as a mass term (it is the so-called dynamicalmass) and spontaneously breaks the chiral symmetry

If temperature increases generally there will be a screening of the interaction and〈ψψ〉(T ) = 0 for T gt Tc where Tc is called the phase transition temperature the chiralsymmetry is said to be restored At approximately the same temperature the decon-finement occurs hence the high temperature phase is also known as the Quark GluonPlasma (or QGP) phase The fact that chiral symmetry restoration and deconfinementare occurring at almost the same temperature happens because in low-energy QCD thereis basically one scale only ΛQCD

4 The observed mass differences are not exactly zero because the u d s mass differences are notexactly zero (isospin limit)

11 Theoretical Baseline 11

minusrarrπσ

Ueff

A

B

a

minusrarrπσ

Ueff

b

minusrarrπσ

Ueff

c

1Figure 14 Effective potential as a function of ~πndashσ left to right going towards fully chirality restora-tion

If one takes σ sim ψψ and ~π sim ψiγ5~τψ the chiral symmetry restoration can be describedin the same way as the Goldstone mechanism related to the Higgs mechanism At lowtemperature one has a Goldstone effective potential Ueff (see figure 14 a) that has the well-known Mexican hat shape the ldquovacuumrdquo (relative to the expectation value 〈~π〉 = 0 = 〈σ〉)is in fact unstable The physical vacuum is located at the bottom of the potential on theso-called chiral circle As the temperature increases the chiral circle shrinks until the state〈~π〉 = 0 = 〈σ〉 is stable (see figure 14 c) this is the restoration of the chiral symmetry

The chiral symmetry restoration has an impact on the in-medium spectral functionsof hadrons the most easily accessible experimental observable related to this mechanismis the ρ meson thanks to its short life-time (13 fmc) allowing it to be produced anddecay inside the volume of the QGP typically obtainable in heavy-ion collisions

113 Hadronic Matter mdash Quark-Gluon Plasma (QGP)

As already remarked low-energy QCD mechanisms are driven by the same scale param-eter ΛQCD this is the reason why chiral symmetry restoration and color deconfinementhappen under the same thermodynamical conditions identifiable in the QCD phase dia-gram shown in figure 15

This schematic diagram presents two main regions The first one is the region atlow temperature and density where quarks and gluons are confined inside hadrons andthe chiral symmetry is broken The second region is characterized by large values oftemperature and or net baryon density where the relevant degrees of freedom are quarkand gluon and is a new state of matter the Quark Gluon Plasma (QGP) These tworegions are separated by a phase transition At vanishing net baryonic density (from 0 toan hypothetical critical point) this frontier is a smooth phase (ldquocross-overrdquo) transitionAt increasing value of net baryonic density beyond an hypothetical critical point thefrontier becomes a first order phase transition At extreme values of the net baryonicdensity and low temperature other hadron phases of the hadronic matter can be possibleas the hypothetic color superconducting phase proposed by some theoretical speculations

The only way to get experimental access to the QCD phase diagram in the regionof deconfinement under controlled conditions is to perform ultra-relativistic heavy-ioncollisions Different regions of the phase diagram can be covered by changing the center-

12 Chapter 1 Physics Motivations

Figure 15 Schematic QCD phase diagram as a function of temperature and net baryon density

of-mass energy of the collision as the energy increases the initial temperature of thesystem increases and its net baryonic density decreases At the high-energy frontier theexperiments carried at the Large Hadron Collider (LHC) at CERN and the RelativisticHeavy-Ion Collider (RHIC) at the BNL are suited to reproduce the conditions of hightemperature and low-net baryonic density present in the early Universe

In this QCD phase diagram there is a hypothetical Critical Point and this pointprovides a major research focus both theoretically and experimentally On the theory sidelattice QCD (LQCD) gives accurate results only at zero density It can be extrapolatedat finite density Another technique is the use of effective models as the NJL one [7] Onthe experimental side studies of heavy-ion collisions are done with several energies andion species (NA61 STAR PHENIX) and they probe different density regimes Finallycompact star observation may also give results about the zero temperature high densityphase of QCD

12 Heavy-Ion Physics Experimental ProgramThe experimental study of QGP needs this state of matter to be recreated in laboratoryAs we have seen in the previous section high density andor temperature are needed inorder to reach the conditions for the creation of the QGP state these conditions are metin ultra-relativistic heavy-ion collisions This experimental tool allows one to change theenergy density of the system by varying the size and the energy of the colliding nuclei

12 Heavy-Ion Physics Experimental Program 13

Several probes of the QGP exist which will be described later in this chapter the design ofa heavy-ion detector directly depends on the probes chosen for the experimental program

The relativistic heavy-ion experimental program started in the early 1980s at the BNLAGS [9] and CERN SPS [10] (collision energy per nucleon pair up to radicsNN asymp 20 GeV)and continues today both at the SPS and at the RHIC [11] and LHC [12] colliders whereenergies up to radicsNN = 02 TeV and 5 TeV are reached respectively

121 Relevant Kinematic Variables

Before discussing collision geometry and QGP probes we briefly introduced the mainkinematic variables of interest for heavy-ion physics and particularly for the study pre-sented in this manuscript

Transverse Momentum (pT) The kinematics of a particle can be described by anenergy-momentum quadrivector In the context of a high-energy experiment where aprivileged axis is defined by the beams the 3-momentum can be conveniently decomposedinto its longitudinal (pz) and transverse (pT) components The transverse momentum isinteresting for two reasons firstly the transverse degree of freedom is created during thecollision since the initial state is characterized only by the longitudinal degree of freedomof the colliding particles secondly the transverse momentum is invariant under Lorentzboosts along the z-axis allowing one to directly compare the pT distributions measuredin fixed-target and collider experiments

Rapidity (y) The longitudinal degree of freedom of a particle kinematics can be con-veniently expressed in terms of the rapidity variable y defined as

y = 12 ln

(E + pzcE minus pzc

) (131)

It can be shown that the rapidity is additive under Lorentz boosts along the z-axisthis allows one to directly compare the shape of the rapidity distributions measured infixed-target and collider experiments

Pseudo-Rapidity (η) In the ultra-relativistic regime where p m and E asymp p therapidity can be approximated by the pseudo-rapidity η

y = 12 ln

(E + cp cos θE minus cp cos θ

)asymp 1

2 ln(

1 + cos θ1minus cos θ

)= minus ln

[tan

(θ

2

)]equiv η (132)

The pseudo-rapidity is especially useful whenever the energy and the longitudinal mo-mentum pz are not available at the same time in this case the pseudo-rapidity providesan approximation of the rapidity based on the measurement of the polar angle θ only (theangle between the z-axis and the particle direction)

14 Chapter 1 Physics Motivations

Invariant Mass In case the particle of interest for a given analysis is not directlyobservable (because of its short life time) its kinematics can still be reconstructed byidentifying and measuring its decay products the quadrivectors of the daughters canbe composed to obtain the quadrivector of the mother particle from which can be easilyobtained its invariant massm2c4 = E2minusp2c2 In the specific case of the analysis presentedin this thesis the φ meson (as well as the other low-mass neutral mesons η ρ ω) hasbeen identified through its decay into two muons

122 Collision GeometryTo clearly interpret the observables in a heavy-ion collision one also needs to characterizeits geometry The two main geometric parameters characterizing a heavy-ion collision arethe centrality and the event plane

Centrality mdash The centrality is a concept related to the finite size of the collidingnuclei in fact heavy nuclei (like the lead nuclei accelerated at the LHC) can be regardedas extended objects consisting of several nucleons Some of these nucleons participate tothe collision and are called participants while the remnants do not interact and are calledspectators see figure 16-left

x

y

ΦRP

Figure 16 Schematic representation of a lead-lead collision

As it can be also seen in figure 16-left an impact parameter b can be identified whenlooking at a nucleus-nucleus collision in the transverse plane If this parameter is nullthe overlap between the two nuclei and the energy available in the overlapping volumeis maximal these collisions are classified as most central For larger impact parametersthe overlap region between the two nuclei and the energy available in the overlappingvolume become smaller these collisions are classified as semi-central semi-peripheral andperipheral for increasing values of b If the impact parameter is larger then two nuclearradii the collision is called ultra-peripheral and there is no hadronic interaction betweenthe two nuclei

The impact parameter in a heavy-ion collision is not directly measurable due to itsfemtoscopic size Yet b (so the centrality of the collision) can be estimated by quantifyingthe produced particle multiplicity since the two quantities are strongly correlated [13]An effective way to establish this correlation is provided by the Glauber Model [14]

In smaller collision systems like pp and p-Pb the measurement of the produced parti-cle multiplicity is still possible giving insight into the energy of the partonic interactions

12 Heavy-Ion Physics Experimental Program 15

involved in the collision (the so-called ldquoevent activityrdquo) However due to the loose corre-lation between this quantity and the geometry of the collision in such small systems [13]no geometrical interpretation can be established in this case

Event plane mdash In case the collision is not head-on it is possible to define the eventplane as a plane formed by the beam direction and the impact parameter The transverseprofile of this plane in non-central nucleus-nucleus collisions is represented in the rightpanel of figure 16 The determination of the event plane orientation event-by-event isimportant to characterize the azimuthal anisotropies observed in the measurement of theparticles produced in the collisions

123 Evolution of a Heavy-Ion CollisionFigure 17 illustrates the evolution of the hadronic collision in the two cases where theQGP is created (right side) or not (left side)

Figure 17 Space time evolution left-side without QGP right-side with QGP

Collisions with creation of QGP mdash In this case a dense and hot system of freepartons is created in the collision the typical size of the system is such that a ther-modynamical approach can be adopted and a medium temperature defined This sys-tem of deconfined quarks and gluons undergoes multiple interactions and the expansioncharacterized by a hydrodynamic-like collective expansion During this expansion thehadronization starts and there is a cooling of the system until the critical temperatureof the transition between the partonic and hadronic phases (Tc) is reached The coolingcontinues the medium is a hadronic gas until the temperature of chemical freeze-out(Tch) is reached (from above) beyond this point the inelastic interactions stop and the

16 Chapter 1 Physics Motivations

composition of hadronic species is fixed The cooling continues until the kinetic freeze-outis reached beyond this point the elastic interactions also stop and the hadrons fly to thedetectors with kinematic distributions characterized by a temperature Th

Collisions without creation of QGP mdash In this case the collision starts by a pre-equilibrium partonic phase which directly leads to the hadronic phase without passingthrough any significant hydrodynamic or thermodynamic evolution After the elasticinteractions between the hadrons stop the species and their kinematics are fixed

124 Experimental Observables of the QGPA variety of observables exists giving insight into the properties of the QGP each ob-servable providing a complementary piece of information

Bulk physics light-flavor radiation

Figure 18 Hadron yields from ALICE at theLHC and fit with the statistical hadronizationmodel [15]

The bulk radiation is mainly composed oflight-flavored hadrons (u d s quarks) Hav-ing a typical scale of 1 fm 1(200 MeV)these hadrons cannot exist inside the decon-fined medium For this reason the light-flavor radiation measured by the detector isformed at the transition between the QGPand the physical vacuum taking place at thecritical temperature Tc 160minus 180 MeVThis fact is confirmed by the good agreementbetween the measured relative abundancesof the main light hadron species (includinglight hypernuclei) and the prediction of a sta-tistical hadronization model with fixed ther-modynamical parameters at the transitionphase see figure 18

The global hydrodynamical flow drivingthe expansion of the deconfined medium in-

duces the radial flow characterizing the light-flavor radiation pT spectrum Experimen-tally it is possible to observe this radial flow by measuring the pT dependence of the yieldfor the various species of the bulk radiation an example is given in figure 19

Moreover if the initial conditions are not spherically symmetric as it is in fact the casein non-central heavy-ion collisions the difference in pressure in different spatial directionswill lead to a further ldquodirectedrdquo or ldquoellipticrdquo flow (characterized by the v2 parametersin the Fourier expansion of the azimuthal particle distribution) Since the elliptic flowdepends on the initial conditions of the expending medium (like the geometry and theshear viscosity) the flow studies of hadron spectra can provide information about theearlier pre-hadronic stages of the collisions For example figure 110 illustrates how the

12 Heavy-Ion Physics Experimental Program 17

Figure 19 Transverse momentum distributionsof the sum of positive and negative particles asmeasured by ALICE fitted individually with ablast wave function compared to RHIC dataand hydrodynamic models [16]

Figure 110 Elliptic flow coefficient of chargedparticle in PbndashPb collisions as a function of cen-trality compared to viscous hydrodynamic re-sults [1718]

shear viscosity (ηs) of the medium can be estimated by the analysis of the centralitydependence of the v2 parameter

Strangeness productionWithin the light-flavor radiation strangeness production plays a peculiar role since thereare no strange valence quarks in the initial state of the collision as opposed to u and dquarks yet they are sufficiently light to be abundantly created in the course of the colli-sions High-pT strangeness production happens either at the early stages of high-energycollisions in hard partonic scattering processes by flavor creation and flavor excitation(see Feynman diagrams in figure 111) or during the subsequent partonic evolution viagluon splittings Low-pT strangeness production is dominated by non-perturbative pro-cesses like string fragmentation however due to the heavier mass of the strange quark(95plusmn 5 MeVc2) than the u and d quarks the production of strange hadrons in fragmen-tation processes is suppressed in comparison to the production of hadrons containing onlyu and d quarks

q

q s

s g

g s

s

g

g s

s g

g s

s

Figure 111 Feynman diagrams in pQCD at first order for the strangeness production inside QGP

18 Chapter 1 Physics Motivations

Figure 112 pT-integrated yield ratios of strange and multi-strange hadrons to (π+ + πminus) as afunction of 〈dNchdη〉 measured in the rapidity interval |y| lt 05 [20]

An enhancement of strange hadron production was historically proposed [19] as anindication of the QGP formation the argument is that strangeness production would beenhanced by the large energy density available in the medium the enhancement scal-ing with the strangeness content of each hadron Figure 112 shows the ratio of strangehadrons over pions as a function of event multiplicity for pp p-Pb and Pb-Pb collisionsIn this figure one can appreciate the difference of the measured enhancement for strangehadrons containing different numbers of strange quarks Ks mesons and Λ baryons con-taining one strange quark Ξ baryons containing two strange quarks and Ω baryonscontaining three strange quarks

JetsIn high-energy collisions a significant production of hard partons is observed thehadronization of these partons produces a narrow cone of hadrons and other particlescorrelated together named jet In heavy-ion collisions jet measurements offer the pos-sibility to probe the deconfined medium by measuring the energy loss of the initial hardparton (jet quenching) and the modification of the jet cone structure and composition(jet broadening) Due to the high energy involved in the production of hard partons jetphysics in heavy-ion collision basically started at RHIC in 2000rsquo whereradicsNN values of theorder of 100 GeV became available for the first time Today jet physics in heavy-ion col-lisions profits from the larger energies available at the LHC implying larger cross-sectionsfor hard scattered partons and an extended range of jet energies

In figure 113 and 114 two examples of jet physics results in heavy-ion collisions are

12 Heavy-Ion Physics Experimental Program 19

Figure 113 The b-tagged jet RAA as a functionof Npart for two jet pT selections in Pb-Pb atradicsNN = 276 TeV in CMS [21]

(GeVc)Tassoc

p1 15 2 25 3 35 4 45

)shyπ

++

π)

(p

(p+

0

02

04

06

08

1

12

1415)plusmn lt η∆06 lt plusmn lt 052 φ∆Bulk Ratio (shy052 lt

lt 04)η∆ lt 052 shy04 lt φ∆Peak shy Bulk Ratio (shy052 lt

Pythia (Peak shy Bulk Ratio)

= 276TeV 0shy10 centralNN

sPbshyPb

lt 100 GeVcTtrig

50 lt p

ALIminusPRELminus15474

Figure 114 Ratio of proton to pion spectraas function of pT for the ldquobulkrdquo and ldquopeak-bulkrdquo [22]

shown In figure 113 the nuclear modification factor (RAA) of b-tagged jets is shown as afunction of Npart as measured by the CMS experiment at the LHC in Pb-Pb collisions atradicsNN = 276 TeV A clear decreasing trend for RAA is observed for increasing values of

Npart interpreted as a manifestation of the jet-quenching mechanism In figure 114 theproton-over-pion ratios in the bulk and in jet are shown as a function of pT measuredby ALICE in Pb-Pb collisions at radicsNN = 276 TeV The comparison of the measuredproton-over-pion ratio in jets (ldquopeak-bulkrdquo) with the prediction from PYTHIA suggeststhat no significant medium-induced modification of particle ratios is at play in jets

Heavy flavorsThe abundant production of c and b quarks at LHC offers a unique possibility to un-derstand the details of the energy loss thermalization and hadronization mechanismscharacterizing the interaction of heavy quarks with the medium

The energy loss can be studied through the measurement of the pT-dependence of thenuclear modification factor RAA for the various heavy flavor hadron species In figures 115and 116 the RAA averaged over the main non-strange D-meson species is compared withthe RAA of light-flavored mesons and (non-prompt) Jψ from B decays respectivelyprobing the suppression hierarchy RB

AA gt RDAA amp Rlight quarks

AA reflecting the different energyloss of light charm and beauty quarks Despite the large uncertainties the data suggesta similar energy loss for the charm and light quark a scenario also supported by sometheoretical models [23] The heavy quark hadronization mechanism in the medium can bestudied by comparing the production of various species of heavy flavor hadrons [2425]

QuarkoniaQuarkonia are resonance states of charm-anticharm (charmonia) or bottom-antibottom(bottomonia) pairs Quarkonium measurements provide information on the properties of

20 Chapter 1 Physics Motivations

Figure 115 Prompt D-meson RAA as a func-tion of pT compared to the pion and charged par-ticles RAA in the 0-10 centrality classes [26]

rangpart

Nlang0 50 100 150 200 250 300 350 400

AA

R

0

02

04

06

08

1

12

14

(empty) filled boxes (un)correlated syst uncertψ() 50shy100 for nonshyprompt J

|lt05y |clt16 GeVT

pD mesons (ALICE) 8lt

= 276 TeVNNsPbshyPb

rangpart

Nlang shifted by +10 in plusmnπ

(CMS)ψ Nonshyprompt J|lt12y |clt30 GeV

Tp 65lt EPJC 77 (2017) 252

50shy80

40shy5030shy40

20shy3010shy20

0shy10

|lt08y |clt16 GeVT

p (ALICE) 8ltplusmnπ

ALIminusPUBminus129313

Figure 116 Comparison of the average D-meson RAA in 8ltpT lt16 GeVc with chargedpions in the same pT range and Jψ from Bdecays in 65ltpT lt30 GeVc [27]

the medium in the early stages of heavy-ion collisions being sensitive to the in-mediumdissociation and recombination mechanisms for the various quarkonium states Quarko-nium dissociation was indeed proposed as a signature of the production of QGP in heavy-ion collisions due to a color-screening effect [28 29] in analogy to the Debye-screeningin electrostatics coupled to a dynamical interaction of the heavy-quark pair with thesurrounding partons [3031]

Figure 117 Dimuon mass spectrum in the Υregion in Pb-Pb collisions at radicsNN = 502 TeVwith CMS experiment [32]

rangpart

Nlang0 50 100 150 200 250 300 350 400

AA

R

0

02

04

06

08

1

12

14-micro+micro rarr ψInclusive J

c lt 8 GeVT

p lt 4 y = 502 TeV 25 lt NN

sPb minusALICE Pb

c lt 8 GeVT

p lt 4 y = 276 TeV 25 lt NN

sPb minusALICE Pb

c gt 0 GeVT

p| lt 22 y = 02 TeV 12 lt |NN

sAu minusPHENIX Au

ALI-DER-112313

Figure 118 The participant number depen-dence of RAA for inclusive Jψ in ALICE in Pb-Pb collisions at radicsNN = 502 and 276 TeVand in PHENIX at forward rapidity in Au-Au atradicsNN = 200 GeV

12 Heavy-Ion Physics Experimental Program 21

The dissociation mechanism resulting in the suppression of the less bound quarkoniumstates is best illustrated in figure 117 showing the dimuon mass spectrum in the Υ regionmeasured by the CMS experiment with the Pb-Pb data at radicsNN = 502 TeV comparedto the expected yield in pp One can observe that the suppression of the Υ(3S) state isstronger than the one of the Υ(2S) with respect to the Υ(1S) due to the different bindingenergy of the two resonance states (sequential melting of quarkonium)

For the charmonium states a statistical recombination mechanism is expected to com-pete with dissociation for sufficiently large values of the cc cross-section expected forinstance in Pb-Pb collisions at the LHC energies The interplay of the suppression andrecombination mechanisms has indeed been proposed to explain the ALICE data for thecentrality dependence of the Jψ RAA in Pb-Pb at radicsNN = 502 and 276 TeV shown infigure 118 together with the PHENIX results in Au-Au collisions at radicsNN = 200 GeVFor 〈Npart〉 gt 120 the ALICE Jψ RAA shows no significant centrality dependence and isalmost a factor of 3 larger than the PHENIX data for the most central points no sizablerecombination mechanism being at play at RHIC energy Further insight on the role ofstatistical recombination in charmonium production at the LHC could come from thecomparison of the Jψ elliptic flow measurements with the theoretical models

Electromagnetic probesElectromagnetic radiation (real photons and dileptons from virtual photons) is emittedfrom a variety of processes prompt photons from initial hard scatterings thermal photonsand medium-modified ρ dileptons from the QGP phase real and dileptons from radiativedecays after hadronization The fact that electromagnetic radiation is emitted during thewhole evolution of the collision represents at the same time an advantage (for instancethe possibility of probing the entire lifetime of the fireball) and a drawback (the variouscomponents being hard to disentangle) Another advantage of electromagnetic radiationis that whenever emitted it is not affected during its propagation by the strong inter-action dominating inside the deconfined medium providing a clean probe of hadronicinteractions

Figure 119 shows the pT spectrum of real photons in Pb-Pb collisions atradicsNN = 276 TeV measured by ALICE for three centrality classes In all centrality

classes no evidence for medium influence is observed at high pT At low pT (gt 2 GeVc)on the contrary an excess of real photons with respect to pQCD real photon productionis observed for mid- and central collisions with a temperature of Teff asymp 300 MeV ex-tracted in central collisions [33] This excess might be related indeed to the productionof thermal photons from the QGP phase

Figure 120 shows the excess in the dimuon mass spectrum with respect tothe expected hadronic sources measured by NA60 in semi-central In-In collisions atradicsNN = 173 GeV compared to various theoretical scenarios This excess is domi-

nated by the medium-modified ρ line shape at low mass (gt 1 GeVc2) and by a thermalcontribution at intermediate mass ( 1 GeVc2) and its study allows one to shed lighton the relevant properties of QGP equation of state [34 35]

22 Chapter 1 Physics Motivations

Figure 119 Direct photon spectra in PbndashPbcollisions atradicsNN = 276 TeV for three central-ity classes compared to model in pp collisions atthe same energy scaled by the number of binarynucleon collisions for each centrality class [33]

Figure 120 Dimuon invariant-mass in semi-central In-In collisions with NA60 [34]

125 Proton-Proton Collisions

Proton-proton collisions present various aspects of interest in the context of heavy-ionphysics namely as a reference for heavy-ion observations test for pQCD calculationsinput for phenomenological non-perturbative models and environment for collectivity insmall systems

As a reference for heavy-ion collisions pp measurements are needed in order hot andcold nuclear matter effects to be properly disentangled respectively in nucleus-nucleusand proton-nucleus collisions This implies two necessities collecting pp reference dataat the same radicsNN energy as more complex collision systems and finding appropriatevariables which could relate pp pA and AA observations A primary example is givenby the nuclear modification factor (RAA) defined as the direct ratio of production cross-sections in AA or pA over the corresponding pp reference scaled by the number of binarycollisions for example to study the charged-particle production [36]

Proton-proton collisions are also an ideal environment for the study of hard and softprocesses in vacuum In the first case (jets Jψ Υ ) one has the possibility to testpQCD calculations in the second case constraints on phenomenological models can bederived in terms of kinematic distributions and production cross-sections [3738]

Finally it is possible to use pp collisions for studying the emergence of collective ef-fects in small systems This study is typically performed analyzing the data in classes ofcharged particle multiplicity the onset of collectivity being driven by the event activityIn this context the observation of collective effects in large-activity pp and p-Pb colli-sions showing striking similarities with those observed in Pb-Pb collisions represents anintriguing challenge for theoretical models [39]

13 Low-Mass Dimuon Measurements in ALICE 23

13 Low-Mass Dimuon Measurements in ALICEThis thesis work is focused on low-mass dimuon measurements in pp collisions atradics = 13 TeV For this reason it is interesting to report here about low-mass dimuon re-

sults and currently ongoing analyses in the other collision systems and energies availableLow-mass dimuon production is studied in ALICE in Pb-Pb collisions atradicsNN = 276 and502 TeV in p-Pb collisions at radicsNN = 502 and 816 TeV as well as in pp collisions atradics = 276 502 7 and 8 TeV Due to the favorable position of its two-body decay in the

low-mass dimuon region with no significant competing sources beyond the smooth cor-related continuum from open heavy flavors the φ-meson has been the privileged subjectof the low-mass dimuon analyses in the first years of LHC operation

Pb-Pb collisionsThe LHC provided Pb-Pb collisions in Run 1 at radicsNN = 276 TeV and in Run 2 atradicsNN = 502 TeVDue to the limited statistics of the Run 1 data the φ-meson study is limited to the

pT range from 20 to 50 GeVc for the dimuons in Pb-Pb collisions at radicsNN = 276 TeVsee figure 121 where the lower limit is imposed by the hardware trigger condition onsingle muons (pT 1 GeVc) and the upper limit is defined by the available statisticsThe analysis of the Run 1 low-mass dimuon data allowed the measurement of the nu-clear modification factor RAA of the φ-meson at forward rapidity in Pb-Pb collisions atradicsNN = 276 TeV shown in figure 122 together with the corresponding ALICE mea-

surement at mid-rapidity and the PHENIX measurement at mid-rapidity in Au-Au andCu-Cu collisions at radicsNN = 200 GeV As can be seen from the comparison of the twoALICE sets of points the RAA does not exhibit any significant dependence on the rapidityregion considered on the contrary the PHENIX points seem systematically higher thanthe ALICE ones although still compatible with the latter within the total uncertaintiesAll the data sets agree on the general decreasing trend of RAA as a function of 〈Npart〉

The larger statistics available from the first Pb-Pb data taking at radicsNN = 502 TeVof Run 2 (2015 a second one being foreseen for 2018) allows the analysis of φ-mesonproduction to be performed up to 7 GeVc starting again from 2 GeVc due to thehardware trigger condition The pT dependence of the φ-meson yield could be studied inseveral centrality classes as shown in figure 123 where the data points are fitted withthe power-law function

dNdpTprop pT[

1 +(pTp0

)2]n (133)

where n and p0 are the free parameters of the fit The centrality dependence of φ-mesonproduction is also studied by looking at the central-to-peripheral ratio RAA as a functionof 〈Npart〉 as shown in figure 124 this dependence suggests a general decreasing trendof RAA as a function of centrality

p-Pb collisionsThe LHC provided in Run 1 p-Pb collisions at radicsNN = 502 TeV and in Run 2 at

24 Chapter 1 Physics Motivations

Figure 121 φ-meson yield as a function of pT inPb-Pb collisions at radicsNN = 276 TeV in threecentrality classes and two rapidity regions [40]

Figure 122 φ-meson RAA as functionof 〈Npart〉 in Pb-Pb collision at radicsNN =276 TeV and Au-Au and Cu-Cu collisions atradicsNN = 200 GeV [40]

)c (GeVT

p

0 1 2 3 4 5 6 7 8

shy1 )c

(G

eV

T

pd

yd

φN

2d

6minus10

5minus10

4minus10

3minus10

2minus10

1minus10

1

10

210

Centr 0shy10 x 8 Centr 10shy20 x 2

Centr 20shy40 Centr 40shy60

Centr 60shy90 Power law

= 502 TeVNN

sPbshyPb

lt 4y25 lt

ALICE Preliminary

ALIminusPRELminus117465

Figure 123 φ yield as a function of pT for fivecentrality classes in Pb-Pb collisions at radicsNN =502 TeV [41]

rang part

N lang

0 50 100 150 200 250 300 350

AA

R

0

05

1

15 = 502 TeV

NNsPbshyPb

shymicro+micro rarr φ

lt 4y25 lt c lt 7 GeV

Tp2 lt

ALICE Preliminary

ALIminusPRELminus131928

Figure 124 φ nuclear modification factor Rcpas a function of Npart in Pb-Pb collisions atradicsNN = 502 TeV [41]

13 Low-Mass Dimuon Measurements in ALICE 25

radicsNN = 816 TeV Because of the different energy of the proton and Pb beams in

p-Pb collisions the nucleon-nucleon center-of-mass moves in the laboratory with a posi-tive rapidity in the direction of the proton beam The directions of the proton and Pbbeam orbits can be inverted during the p-Pb data taking periods allowing the ALICEmuon spectrometer to access a forward rapidity region when the proton beam is directedtowards the muon spectrometer (203 lt y lt 353) and a backward rapidity region whenthe Pb beam is directed towards the muon spectrometer (minus446 lt y lt minus296)

y

shy4 shy2 0 2 4

(b

)y

dφ

σd

0

005

01

015

02data

HIJING

DPMJET

=502 TeVNN

sALICE pshyPb

c lt 7 GeVT

p1 lt

ALI-PUB-94059

Figure 125 φ-meson cross-section as a func-tion of y in p-Pb collisions at radicsNN = 502 TeVand 10 lt pT lt 70 GeVc Predictions fromHIJING and DPMJET are also shown for com-parison

)c (GeVT

p

0 1 2 3 4 5 6 7

)shymicro

+micro

rarr φ

(F

BR

0

05

1

15

data

HIJING

DPMJET

=502 TeVNN

sALICE pshyPb

|lt353y296lt|

ALI-PUB-94063

Figure 126 φ-meson forward-backward cross-section ratio as a function of pT for 296 lt |y| lt353 in p-Pb collisions at radicsNN = 502 TeVPredictions from HIJING and DPMJET are alsoshown for comparison

Figure 125 reports the φ-meson cross-section as a function of y for p-Pb collisions atradicsNN = 502 TeV showing a clear asymmetry between the forward and backward regions

not reproduced by the predictions of HIJING and DPMJET also shown To establish a moredirect comparison of the φ-meson cross-section in the forward and backward regions thecross-section was extracted as a function of pT in the common |y| range 296 lt |y| lt 353in terms of the ratio RFB between the forward and backward cross-section shown infigure 126 The observation of RFB values significantly different than 1 is consistent withthe observation of the asymmetry in the y dependence of the cross-section reported infigure 125 No significant pT dependence of RFB is visible within statistical and systematicuncertainties

p-Pb data have also been taken in 2016 at radicsNN = 816 TeV with a total integratedluminosity larger than the one of the radicsNN = 502 TeV data taking (see table 22) Theanalysis of this data is currently ongoing and is expected to produce the first preliminaryresults in 2018

pp collisionsLow-mass dimuon data in pp collisions are available at several center-of-mass energiesradics = 276 7 and 8 TeV (data taken during the LHC Run 1) 502 and 13 TeV (data

taken during the LHC Run 2)

26 Chapter 1 Physics Motivations

pp results atradics = 276 TeV [13] are used as a reference for Pb-Pb collisions at

the same radicsNN Figure 127 shows the opposite-sign dimuon signal (after combinatorialbackground subtraction) integrated over the available pT and y ranges compared to theresult of the hadronic cocktail fit the good quality of the data-MC comparison leads toa robust extraction of the φ-meson signal Figure 128 shows the φ-meson differentialcross-section as a function of pT compared to the Levy-Tsallis function [42]

1pT

dNdpTprop1 +

radicpT2 +m2

φ minusmφ

nT

minusn (134)

with n and T as free parameters In figure 128 data are also compared to the predictionsby PHOJET and PYTHIA tunes ATLAS-CSC D6T Perugia0 and Perugia11 As one cansee a good agreement is found between predictions and data except for PYTHIA tunesPerugia0 and Perugia11 which underestimate the cross-section measurement

)2c (GeVmicromicroM

0 02 04 06 08 1 12 14

)2

c (

dim

uo

ns p

er

25

Me

V

micromicro

Md

Nd

0

05

1

15

310times

micromicro

rarrρ

0πmicromicrorarrω

micromicro

rarr φ

γmicromicrorarrrsquoηmicromicro rarr bb

γmicro

micro rarr

η

micromicro

rarr ω

micromicro rarr cc

= 276 TeVspp

lt 4y25 lt

c lt 5 GeV T

p1 lt

micromicro

rarr η

ALICE

ALI-PUB-94035

Figure 127 Dimuon opposite-sign mass spec-trum in pp collisions at

radics = 276 TeV af-

ter combinatorial background subtraction pT-and y-integrated data compared to the hadroniccocktail fit [13]

)c (GeVT

p

0 1 2 3 4 5

))c

(m

b(

Ge

V

Tp

dy

dφ

σ2

d

shy310

shy210

shy110

1 = 276 TeVsALICE pp

lt 4y25 lt

Data

PYTHIA ATLASshyCSC

PYTHIA D6T

PYTHIA Perugia0

PYTHIA Perugia11

PHOJET

LevyshyTsallis

ALI-PUB-94047

Figure 128 φ-meson cross-section as a func-tion of pT in pp collisions at

radics = 276 TeV

Predictions from PHOJET and PYTHIA are alsoshown for comparison as well as the result of afit with a Levy-Tsallis function [13]

Low-mass dimuon data taken in 2015 in pp collisions atradics = 502 TeV offer the

possibility to establish a data-based reference for Pb-Pb and p-Pb data at the sameenergy The opposite-sign dimuon signal in pp collisions at

radics = 502 TeV is shown

in figure 129 integrated over the available pT and y ranges compared to the resultof the hadronic cocktail fit the good quality of the data-MC comparison allows for arobust extraction of the φ-meson signal The pT-differential φ-meson cross-section couldbe extracted up to 6 GeVc as shown in figure 130 compared to different theoreticalmodels

Low-mass dimuon data in pp collisions atradics = 7 TeV allowed for the study of the pT-

differential ω and φ cross-sections The hadronic cocktail fit on the isolated opposite-signdimuon signal is shown in figure 131 The identification of the ω and the φ meson signals

13 Low-Mass Dimuon Measurements in ALICE 27

)2c (GeVmicromicroM

0 02 04 06 08 1 12 14

)2

c (

dim

uo

ns p

er

25

Me

V

micromicro

Md

Nd

1000

2000

3000

4000 = 502 TeVspp

lt 4 y25 lt c lt 7 GeV

Tp1 lt

γmicro

microrarr

η

micromicrorarrρ

micromicro

rarrω

0πmicromicrorarrωmicro

microrarr

φ

γmicromicrorarrrsquoη

cc

bb

γmicro

microrarr

η

micromicrorarrρ

micromicro

rarrω

0πmicromicrorarrωmicro

microrarr

φ

γmicromicrorarrrsquoη

cc

bb

ALICE Preliminary

ALIminusPRELminus131989

Figure 129 Dimuon opposite-sign mass spec-trum in pp collisions at

radics = 502 TeV af-

ter combinatorial background subtraction pT-and y-integrated data compared to the hadroniccocktail fit [41]

)c (GeVT

p

0 1 2 3 4 5 6 7 8

))c

(m

b(

Ge

V

Tp

dy

dφ

σ2

d

3minus10

2minus10

1minus10

1 = 502 TeVspp

ATLASshyCSCD6TPerugiashy0

Perugiashy11PhojetMonashshy2013

ALICE Preliminary

lt 4y25 lt

ALIminusPRELminus132725

Figure 130 φ-meson cross-section as a functionof pT in pp collisions at

radics = 502 TeV [41]

resulted in the measurements of the pT differential cross-section shown in figure 132 for theω-meson only calculation based of PHOJET and PYTHIA with ATLAS-CSC and D6T tunesfairly agree with the data while the Perugia0 and Perugia11 PYTHIA tunes underestimatethe cross-section by about a factor of 2 and 25 respectively (the same conclusions standfor φ-meson)

)2M (GeVc

0 02 04 06 08 1 12 14

)2

dN

dM

(p

air

s p

er

25 M

eV

c

0

1000

2000

3000

4000

cc

micro micro

rarr φ

micro micro

rarr ω

micro micro rarr ρ

γ micro

micro rarr

η

micro micro

rarr η

0π micro micro rarr ω

γ micro micro rarrrsquo η

lt 5 GeVct

1 lt p

= 7 TeVsALICE pp

25 lt y lt 4

ALIminusPUBminus26621

Figure 131 Dimuon opposite-sign mass spec-trum for pp collisions at

radics = 7 TeV after com-

binatorial background subtraction pT- and y-integrated sample compared to the result of thehadronic cocktail fit [43]

Figure 132 ω-meson cross-section as a func-tion of pT in pp collisions at

radics = 7 TeV com-

pared to the predictions of various phenomeno-logical models [43]

Finally low-mass dimuon data are also available in pp collisions atradics = 8 TeV This

28 Chapter 1 Physics Motivations

)2c (GeVmicromicroM

0 02 04 06 08 1 12 14

)2

c (

dim

uo

ns p

er

25

Me

V

micromicro

Md

Nd

0

2000

4000

6000

8000

10000

12000 ALICE Preliminary

s = 8 TeVradicpp

25 lt y lt 4

c lt 80 GevT

p15 lt

γmicromicro

rarr

η

γmicromicro rarrrsquo η0πmicromicro rarr ω

bb

micromicro

rarr ω micro

micro rarr φ

micromicro rarr ρcc

ALIminusPRELminus133143

Figure 133 Dimuon opposite-sign mass spec-trum in pp collisions at

radics = 8 TeV after com-

binatorial background subtraction pT- and y-integrated data compared to the hadronic cock-tail fit [41]

)c (GeVT

p

0 1 2 3 4 5 6 7 8

))c

(m

b(

Ge

V

Tp

dy

d φσ

2d

3minus10

2minus10

1minus10

1hEmpty

Entries 0

Mean x 0

Mean y 0

Std Dev x 0

Std Dev y 0

s = 8 TeVradicpp ATLASshyCSCD6TPerugiashy0Perugiashy11

PhojetMonashshy2013

ALICE Preliminary

lt 4 y25 lt

ALIminusPRELminus133207

Figure 134 φ-meson cross-section as a functionof pT in pp collisions at

radics = 8 TeV [41]

offers the possibility to enrich the study of light neutral meson production in pp collisionsas a function of

radics providing at a same time a useful reference for the p-Pb data at

the same radicsNN energy The available statistics larger than the one in pp collisions atradics = 7 TeV allows to extract the low-mass dimuon analysis up to pT = 80 GeVc On

the other side the higher single muon threshold implies that the analysis could only startfrom pT = 15 GeVc The pT- and y-integrated opposite-sign dimuon signal is shown infigure 133 with the associated hadronic cocktail fit Figure 134 shows the extracted φcross-section as a function of pT compared to three predictions of EPOS-LHC and PYTHIA-8with and without multiple parton interactions As one can see the EPOS-LHC predictionoverestimates the φ cross-section while the comparison to the PYTHIA-8 predictions seemsto favor a scenario including multiple parton interactions

Chapter 2

ALICE at the CERN LHC

Summary21 The Large Hadron Collider 29

211 The CERN accelerator complex 29212 The LHC schedule 30213 The Experimental Heavy-Ion Program 32

22 A Large Ion Collider Experiment (ALICE) 33

221 The Central Barrel 34222 The Forward Detectors 36223 The Muon Spectrometer 38224 The ALICE software framework 40225 The ALICE Upgrade 41

21 The Large Hadron ColliderThe Large Hadron Collider (LHC) straddling the FrenchSwiss border in average100 meter underground in a circular tunnel of some 27 km of circumference is as fornow the worldrsquos largest and most powerful particle collider It operates at the TeVenergy scale with nominal energy of 14 TeV (in pp collision) and 55 TeVnucleon pair(in Lead-Lead) foreseen to be achieved in 2018 To carry out this technical challengethe CERN machine engineers developed a new accelerating technique based on supercon-ducting magnets (NbTi) cooled down to a temperature below 2 K which can generatemagnetic fields up to 8 T Four main experiments have been installed within the LHCring namely ATLAS (A Toroidal LHC ApparatuS) CMS (Compact Muon Solenoid)LHCb (LHC-beauty) and ALICE (A Large Ion Collider Experiment) ALICE will bedescribed in more details in section 22

211 The CERN accelerator complexFigure 21 displays the LHC ring and the full complex of accelerators upstream the LHCFollowing a complete trip from the proton source to the final output within the LHCprotons are produced in the LINAC 2 and then injected in the BOOSTER (PSB forProton Synchroton Booster) first accelerator ring This accelerating stage increases the

30 Chapter 2 ALICE at the CERN LHC

Figure 21 The LHC and the CERN accelerator complex [44]

proton energy from 50 MeV to 14 GeV Once protons have reached the top PSB energythey are injected into the Proton Synchroton (PS) where their energy is ramped up to25 GeV and then into the Super Proton Synchrotron (SPS) (7 km in circumference) tothe nominal energy of 450 GeV The latter is the LHC injector and is used in parallel toprovide particle beam to other CERN experiments (for example NA61SHINE)

In the case of the LHC heavy ions runs the lead ions are firstly accelerated in aLINAC 3 then further accelerated in the Low Energy Ion Ring (LEIR) which increasesthe lead energy from 42 MeV to 72 MeVnucleon before injection in the PS The leadions are then accelerated and injected in the SPS and from there to the LHC

212 The LHC schedule

During the first LHC run (Run 1 2009ndash2013) several energies and three collision systems(pp p-Pb Pb-Pb) have been explored In pp collisions five different center-of-massenergies have been considered 09 236 276 7 and 8 TeV p-Pb and Pb-Pb collisionshave been measured at radicsNN = 502 TeV and radicsNN = 276 TeV respectively Run 1was followed by a first Long Shutdown (LS1) mainly dedicated to the upgrade of theaccelerator system mdash resulting in an increase of the collision energy from 7minus 8 TeV to13minus 14 TeV in proton-proton collisions (from 276 TeV to 502 TeV in Pb-Pb collisions)mdash and the completion of the detectors of some of LHC experiment (in the case of ALICEthe electromagnetic calorimeter and the Transition Radiation Detector were updated)Run 2 started in mid-2016 and is planned to last until the end of 2018 with pp collisionsdelivered at 502 and 13 TeV Pb-Pb collisions delivered at radicsNN = 502 TeV and p-Pbcollision delivered at radicsNN = 502 minus 8 TeV LS2 is foreseen to start at the beginningof 2019 ending in late 2020 during LS2 the installation phase of the ALICE upgrade

21 The Large Hadron Collider 31

program will take place During Run 3 pp and Pb-Pb collisions will be delivered atthe nominal LHC energy (14 TeV for pp and radicsNN = 55 TeV for Pb-Pb) and the firstPb-Pb data taking at high-luminosity will take place LS3 will be mainly devoted to theinstallation of the High-Luminosity LHC (HL-LHC) providing unprecedented luminositiesin pp collisions at the designed LHC energy During LS3 the CMS and ATLAS upgradeprograms will be finalize Run 4 will see the beginning of the HL-LHC program in ppcollisions and the continuation of the high-luminosity heavy ion program

Figure 22 LHC schedule for 2015 to 2035 [45]

a Delivered Luminosity Measurement in ALICE

In high energy physics the luminosity is an essential concept expressing the interactionrate normalized to the intensity of the interacting fluxes of particles In the specific caseof a collider with beam pulsing the luminosity is defined by equation (21) where Nb

is the number of particles per bunch nb is the number of bunches per beam frev therevolution frequency γ is the relativistic gamma factor εn the normalized transversebeam emittance βlowast the beam beta function at the interaction point (for more details seechapter 4 of [46]) and F the geometric luminosity reduction factor due to the crossingangle at the interaction point (IP) [47]

L = N2b nbfrevγ

4πεnβlowastF (21)

The luminosity determination in ALICE is based on visible cross section measurementsperformed during van der Meer (vdM) scans [48 49] In standard vdM scans the twobeams are moved across each other in transverse directions x and y The two scans are

32 Chapter 2 ALICE at the CERN LHC

performed separately and the visible cross section is given by the detectors used for thedefinition of the minimum bias triggering conditions typically the V0 and T0 in ALICE

213 The Experimental Heavy-Ion ProgramThe goal of the LHC heavy-ion program is to produce the hottest the largest and thelongest-lived volumes of QGP in laboratory and to provide a precise characterizationof this new state of matter For that nucleus-nucleus collisions (A-A) are delivered atenergies up to radicsNN = 55 TeV Proton-proton and proton-nucleus collisions are also partof the LHC heavy-ion program providing the needed baseline (in terms of vacuum-likecross-sections and cold nuclear matter effects) allowing for a correct interpretation of theobservations in A-A collisions

In addition to the LHC there are other experimental complexes developing specificheavy-ion programs The most important one is the experimental program implementedat the Relativistic Heavy Ion Collider (RHIC) [50] hosted at the Brookhaven NationalLaboratory (BNL) in Long Island (New York US) RHIC is a dedicated heavy-ion facilityand it has a large flexibility in the choice of both the nuclear species accelerated (fromprotons to Uranium) and the center-of-mass energy (in the range radicsNN = 75minus200 GeV)Four detectors are installed at RHIC one of them STAR still operates today whilePHOBOS BRAHMS and PHENIX completed there operations respectively in 2005 2006and 2016 At CERN a fixed-target heavy-ion program complementary to the LHC one isalso running at the SPS with the NA61SHINE experiment [51] currently performing asystematic scan both in beam energy (radicsNN = 45minus 173 GeV) and colliding system size

In addition to the upgrade of some of the existing experiments several new heavy-ionprograms are under discussion or already in preparation [52]

bull The NICA1 facility at JINR [53] will operate in collider mode in the center-of-massenergy range radicsNN = 4 minus 11 GeV and in fixed-target mode in the center-of-massenergy range radicsNN = 19minus 24 GeV

bull The FAIR2 [54] facility at GSI3 will provide fixed-target collisions in the center-of-mass energy range radicsNN = 2minus 29 GeV

bull The AFTER4 project [55] aiming at running a fixed-target heavy-ion program withthe LHC beams at a center-of-mass energy of radicsNN asymp 72 GeV

bull The NA60+ [5657] is a project of fixed-target experiment based at the SPS focusingon dimuon observables at a center-of-mass energy range radicsNN = 63 ndash 173 GeV

1Nuclotron-based Ion Collider fAcility2Facility for Antiproton and Ion Research3Gesellschaft fuumlr Schwerionenforschung mbH4A Fixed Target ExpeRiment at LHC

22 A Large Ion Collider Experiment (ALICE) 33

22 A Large Ion Collider Experiment (ALICE)

Figure 23 Scheme of the ALICE detector

ALICE is an experiment optimized for the study of the physics of strongly interactingmatter at extremely high energy density focusing in particular on the investigation of theQGP state and the characterization of its properties A key design consideration drivingthe developement of the ALICE detector is the possibility to study the most energeticPb-Pb collisions delivered by the LHC This is done by measuring the particles emergingfrom the interaction region it is achieved by ALICE by exploiting a rich variety of sub-detectors see figure 23 based on different technologies described in the following sections[58] Beyond the heavy-ion program ALICE is also interested in collecting data in proton-proton (pp) and proton-Lead (p-Pb) collisions where no large volumes of deconfinedmatter are supposed to be produced to be used as a reference for the Pb-Pb ones

In table 21 and table 22 the ALICE running conditions in the LHC Run 1 and Run 2respectively are summarized

System ECM [TeV] Year Delivered luminosity

pp

09 2009 196 microbminus1

236 2009 087 microbminus1

276 2011 46 nbminus1

2013 129 nbminus1

7 2010 05 pbminus1

2011 49 pbminus1

8 2012 97 pbminus1

p-Pb 502 2012 15 microbminus1

2013 0891 nbminus1 and 140 nbminus1

Pb-Pb 276 2010 9 microbminus1

2011 146 microbminus1

Table 21 Summary of Run 1 ALICE data taking considered for published or ongoing analyses [59]

34 Chapter 2 ALICE at the CERN LHC

System ECM [TeV] Year Delivered luminosity

pp

502 2015 14951 nbminus1

132015 694 pbminus1

2016 1335 pbminus1

2017 192 pbminus1

p-Pb 502 2016816 2016 868 nbminus1 and 124 nbminus1

Pb-Pb 502 2015 280 microbminus1

Table 22 Summary of Run 2 ALICE data taking considered for published or ongoing analyses [59]

221 The Central Barrel

The ALICE central barrel refers to the assembly of detectors installed around the inter-action point inside the L3 magnet These detectors are dedicated to the tracking andidentification of isolated charged particles and photons as well as to the reconstructionof jets

Inner Tracking System (ITS)

The Inner Tracking System (ITS) is the internal tracker of ALICE It is formed by sixcylindrical layers of silicon detector the innermost one having an internal radius of 39 cmlimited by the external radius of the beam pipe The radius of the outermost layer is430 cm The geometric parameters of the ITS are summarized in table 23

sub-system name layer technology r(cm) plusmnz(cm)

SPD 1 Pixel 39 1412 Pixel 76 141

SDD 3 Drift 150 2224 Drift 239 297

SSD 5 Strip 380 4316 Strip 430 489

Table 23 ITS Geometric features

The pseudo-rapidity coverage of the ITS is |η| lt 09 The six layers are grouped intosix groups of two layers each differing by the adopted technology The two innermost lay-ers are composed of silicon pixel detectors (SPD) the central one of silicon drift detectors(SDD) the two outermost are composed of silicon strip detectors (SSD) The ITS allowsthe position of the primary and secondary (from strange and charmed particles) verticesto be determined with a resolution better than 200 microm in rφ and 300 microm in z directionFurthermore it contributes to the particle identification complementing the informationprovided by the TPC especially for the low momentum particles (p lt 200 MeVc)

22 A Large Ion Collider Experiment (ALICE) 35

Time Projection Chamber (TPC)

The Time Projection Chamber (TPC) is the main detector of the central barrel It iscomposed of a 51 m long cylindrical drift volume of 90 m3 developing between an innerradius of 85 cm and an outer radius of 247 cm This volume is filled with NendashCO2 and isdivided into two parts by the central cathode which is kept at minus100 kV The end platesare equipped with multiwire proportional chambers (MWPC) As the ITS the pseudorapidity coverage is |η| lt 09 In addition to tracking the TPC provides charged-particleidentification via measurement of the specific ionization energy loss dEdx Due to theadopted technology and the large size the TPC is the slowest detector of ALICE thuslimiting the interaction rate that can be supported

Transition Radiation Detector (TRD)

The Transition Radiation Detector (TRD) is composed of eighteen super-modules dividedinto thirty modules arranged in six radial layers and five sectors along the beam directionThe TRD has full azimuth coverage and spans the pseudo-rapidity region |η| lt 09This sub-detector provides particle identification for electrons of momentum larger than1 GeVc

Time-Of-Flight (TOF)

The Time Of Flight (TOF) detector allows the particle time-of-flight to be measuredThe TOF coverage is |η| lt 09 in full azimuth It has a modular structure organized intoeighteen sectors in azimuth and five modules along the beam axis The whole detectoris inscribed in a cylindrical volume with an internal radius of 370 cm and an externalone of 399 cm The TOF has an intrinsic time resolution of about 50 ps thanks to thetechnology of Multi-Resistive Plate Chambers (MRPC)

High-Momentum Particle Identification Detector (HMPID)

The ALICE HMPID is based on proximity focusing Ring Imaging Cherenkov (RICH)counters and consists of seven modules mounted in an independent support cradle fixedto the space frame at the radial distance of 490 cm from the interaction point Thepseudo-rapidity acceptance is |η| lt 06 and an azimuthal coverage develops between 1and 59 corresponding to 5 of the central barrel acceptance The HMPID allows oneto extend the particle identification for π and K up to pT asymp 3 GeVc and pT asymp 5 GeVcfor protons

PHOton Spectrometer (PHOS)

The PHOton Spectrometer (PHOS) is a high resolution electromagnetic spectrometercovering the pseudo-rapidity range |η| lt 013 and the azimuth between 220 to 320 andinstalled at the radial distance of 460 cm The detector technology is based on lead-tungstate (PbWO4) crystals The PHOS is used to detect photons in the transversemomentum range between 05 to 10 GeVc including diphotons coming from the decayof the light pseudoscalar neutral mesons

36 Chapter 2 ALICE at the CERN LHC

ElectroMagnetic Calorimeter (EmCal)

The ElectroMagnetic Calorimeter (EMCal) and its extension the Di-jet Calorimeter(DCal) are sampling electromagnetic calorimeters with the pseudo-rapidity coverage|η| lt 07 and azimuth coverage from 80 to 187 (for the EMCal) and 260 to 327 (for theDCal) Specific allowance is made in the DCal acceptance for the space occupied by thePHOS detector The combined information of the EmCal and the DCal allows to studyjets and di-jets providing trigger signals for hard jets photons and electrons

222 The Forward DetectorsIn this section the ALICE sub-detectors covering the forwardbackward acceptance regionare presented These detectors are used to measure global observables especially thecentralityactivity of the collisions and the event plane

Forward Multiplicity Detector (FMD)

The Forward Multiplicity Detector (FMD) is based on the silicon strip technology Itis divided in seven disks perpendicular to the beam pipe located at distances between42 and 225 cm from the interaction point The goal of this sub-detector is to study thecharged particle multiplicity in the pseudo-rapidity ranges minus34 lt η lt minus17 and17 lt η lt 51 complementary to the one of the ITS

T0

The T0 is composed of two arrays of Cherenkov counters circularly arranged around thebeam pipe with a time resolution better than 50 ps The forward and backward parts ofthis sub-detector are located at 375 cm and minus727 cm covering a pseudo-rapidity rangeof 461 lt η lt 492 and minus328 lt η lt minus297 respectively It participates to thetrigger decision and to the estimation of the luminosity

V0

The V0 is composed of two scintillator disks installed around the beam axis on each sideof the interaction point The V0-A (for A-side corresponding to positive values of z) isinstalled at 329 cm from the interaction point it has a diameter of 100 cm and covers thepseudo-rapidity range 28 lt η lt 51 The V0-C (for C-side corresponding to negativevalues of z) is installed at minus90 cm from the interaction point it has a diameter of 74 cmand covers the pseudo-rapidity range minus37 lt η lt minus17

The V0 measures the charged particle multiplicity and by the measurement of thetime-of-flight difference between the A and C scintillators makes possible to identify andreject the beam-gas5 events This technique is illustrated in figure 24 beam-beam andbeam-gas events can be easily discriminated on the basis of the time correlation of thetwo signals reported on the x and y axes

5 A beam-gas event corresponds to an interaction between a beam ion and a nucleus of the residualgas in the beam pipe vacuum

22 A Large Ion Collider Experiment (ALICE) 37

Figure 24 Weighted average time-of-flight of the particles detected in V0-C versus V0-A Thedashed line intersection represents the time of the collisions at the interaction point or the crossingtime of the background tracks at the vertical plane z = 0 [60]

The V0 participates in the minimum-bias trigger decision and in the estimation of theluminosity Furthermore this sub-detector is involved in the centrality measurement inPb-Pb collisions

Photon Multiplicity Detector (PMD)

The Photon Multiplicity Detector (PMD) consists of two identical planes of detectorsmade of gas proportional counters with honeycomb structure and wire readout with Leadconverter in between located at 360 cm from the interaction point in opposite side ofmuon spectrometer The PMD covers the pseudo-rapidity region (23 lt η lt 37) Itmeasures the multiplicity and spatial distribution of photons and estimates the transverseelectromagnetic energy and the reaction plane event-by-event

ALICE Diffractive Detector (AD)

The ALICE Diffractive detector (AD) is a ALICE sub-detector which was installed dur-ing the Long Shutdown 2 (2013-2014) The goal of this sub-detector is to increase thepseudo-rapidity coverage (from 88 to 132 units) and to enhance trigger efficiency forlight particles produced in diffractive events This sub-detector also participates in theestimation of the multiplicity event-by-event It is composed of two double layers of scin-tillator counters one on each side of ALICE sensitive to charged particles with pT downto 20 MeVc In the A-side AD is installed at z = 170 m and covers the pseudo-rapidityrange 49 lt η lt 63 In the C-side the sub-detector is installed at z = minus195 m andcovers the pseudo-rapidity range minus70 lt η lt minus48

38 Chapter 2 ALICE at the CERN LHC

Zero Degree Calorimeter (ZDC)

The Zero Degree Calorimeter (ZDC) is composed of two identical sets of quartz spaghetticalorimeters located on both sides of the ALICE detector in fully horizontal position1125 m from the interaction point Each set of detectors consists of a neutron anda proton calorimeter Each of the neutron calorimeters has dimensions 7x7x100 cm3

while the proton calorimeters have dimensions 228x12x150 cm3 The ZDC detector iscompleted by two small electromagnetic calorimeter (ZEM) placed at 735 m from theinteraction point on one side detecting the energy of particles emitted in the pseudo-rapidity range 48 lt η lt 57 The ZDC is used to estimate the centrality in Lead-Leadcollisions

223 The Muon Spectrometer

Figure 25 The ALICE muon spectrometer layout [61]

The ALICE muon spectrometer (represented in figure 25) is 17 m long Thepseudo-rapidity coverage is minus40 lt η lt minus25 corresponding to the angular range171 lt θ lt 178 The muon spectrometer was designed to study quarkonia (Jψand Υ families) and light vector meson production (η ρω and φ) through their dimuondecays and open charm and beauty production (B and D hadrons) in the single-muonchannel The spectrometer is composed of several elements described in the followingsections

a Front Absorber

The first element of the ALICE muon spectrometer starting from the interaction pointis the front absorber (or hadron absorber) The hadron absorber suppresses all particlesexcept muons coming from the interaction vertex (mainly πplusmn and Kplusmn) It is made of

22 A Large Ion Collider Experiment (ALICE) 39

carbon and concrete (cf figure 26) in order to limit the multiple scattering and theenergy loss of the muons The inner beam shield protects the tracking chambers frombackground originating from particles at small angles It is made of tungsten lead andstainless steel to minimize the background arising from primary particles emitted in thecollision and from their showers produced in the beam pipe and in the shield itself

Figure 26 The ALICE front absorber structure [62]

The absorber is located 90 cm away from the interaction point just after the V0-Cand is 413 cm long

b Dipole Magnet

The dipole magnet provides a maximum magnetic field of 07 T and an integral fieldof 3 T middot m It is a warm magnet (one of the largest warm dipoles in the world) andit is cooled with a demineralized water-cooling system ensuring operating temperaturesbetween 15 to 25 C Its dimensions are 5 m in length 71 m in width and 9 m in heightThe dipole is centered at 994 m from the interaction point and the free gap betweenpoles has a diameter of approximately 3 m The dipole is designed to provide a horizontalmagnetic field perpendicular to the beam axis and its polarity can be reverted Themagnetic field is defined by requirements on the mass resolution for the heavy Υ states

c Tracking Chambers

The tracking system of the muon spectrometer is composed of five stations each sta-tion made of two chambers The distance between two chambers of a same station isbetween 10 and 20 cm The chambers are based on a Multiwire Proportional Cham-ber (MWPC) technology with pad-segmented cathodes [63] The tracking system wasdesigned to achieve the spatial resolution of 100 microm in the bending plane needed for ob-taining an invariant mass resolution of sim 100 MeVc2 at the Υ mass The segmentationof the cathodes allows the spectrometer to operate with maximum hit densities of about5 middot 10minus2 cmminus2 sufficiently large to cope with the observed multiplicity in central Pb-Pbcollisions

40 Chapter 2 ALICE at the CERN LHC

d Iron Wall

The iron wall complements the hadron absorber It is 12 m thick and covers a transversesurface of 56times 56 m2 It is located 15 m away from the interaction point before thetrigger chambers The goal of this element is to suppress all hadrons emerging from thefront absorber The combined action of the iron wall and the front absorber imposesthe muons to have a minimum momentum of sim 4 GeVc in order to reach the triggerchambers

e Trigger Chambers

The ALICE muon spectrometer is equipped with two trigger stations allowing events ofinterest for the muon physics to be selected Each station is composed of two chambersbased on the Resistive Plate Chamber (RPC) technology ensuring the time resolution of2 ns necessary for the identification of the bunch crossing The first station is located at16 m just after the iron wall and the second station at 17 m

Several trigger conditions are hard-coded in the trigger electronics The electronicsprovides the possibility to use two pT thresholds used for different physics and the list oftriggers is

bull MSL at least one muon with pT larger than the low-pT threshold

bull MSH at least one muon with pT larger than the high-pT threshold

bull MLL at least two muons of same charge with pT larger than the low-pT threshold

bull MUL at least two muons of opposite charge with pT larger than the low-pT thresh-old

In addition to these trigger conditions the A-pT trigger condition can also be defined itis the minimum-pT trigger threshold for which a muon is firing the trigger and the valueof this trigger is 05 GeVc

In LHC Run 2 the single-muon high-pT threshold was set to 42 GeVc while thevalue of the single-muon low-pT threshold depended on the data taking periods In thepp data taking during Run 2 two different values have been considered for the single-muonlow-pT threshold 1 GeVc allowing one to access φ meson pT down to sim 15 GeVc and05 GeVc allowing one to access φ meson pT down to almost 0 GeVc

224 The ALICE software frameworkThe ALICE software (AliRoot [64] and AliPhysics [65]) is based on ROOT [66] a soft-ware originally designed at CERN for particle physics data analysis ROOT AliRoot andAliPhysics are written in C++ and are used to handle the online-offline data The soft-ware also manages the Monte-Carlo simulation framework by interfacing several MCgenerators (PYTHIA [67] HIJING [68]) and particle transport codes which simulate thedetector response (GEANT3 [69] GEANT4 [70] and FLUKA [71])

The working flow of the ALICE software is represented in figure 27 where the mainstructures of the online-offline handling are shown The reconstruction steps are the

22 A Large Ion Collider Experiment (ALICE) 41

same for the raw data and MC data At the end of the reconstruction chain the dataare available in the AOD format (Analysis Object Data) From the AOD data furtherdata formats can be derived designed for any specific analysis In the case of the analysisperformed in this thesis the AOD events are reduced to the AliLMREvent format containingthe information of interest for the study of light-neutral meson production decaying intomuons

Simulation Reconstruction

Mon

teCarlo

RealData

Particles

HitsSDigitsSDigits Digits

Clusters

Vertex

Tracks ESD AOD

Trigger

Detector

HLT

DAQ Raw Data

Online Offline

Figure 27 Schema of the reconstruction chain for data and simulation

225 The ALICE UpgradeDuring LHC Run 1 and Run 2 the goal of ALICE is to explore the unprecedented energyregime available in heavy ion collisions see section 124 In the LHC Run 3 and Run 4ALICE we move from the exploration phase to a precision-measurement phase For thisreason ALICE is undertaking a complex upgrade program of its detectors with theinstallation of the upgraded sub-detectors to take place in 2019ndash2020 during the LHCLong Shutdown 2

Physics Motivations

The ALICE upgrade will preserve the specificities of the ALICE physics program withrespect to the other LHC experiments The track reconstruction performance will beimproved in terms of spatial precision and efficiency in particular for low-momentumparticles in order to select more efficiently the decay vertices of heavy-flavor mesons andbaryons The particle identification capabilities of the apparatus will be consolidatedthey represent a crucial tool for the selection of heavy-flavor quarkonium and dileptonsignals at low momentum In the following the main items of the foreseen physics programare shortly reviewed

42 Chapter 2 ALICE at the CERN LHC

bull Heavy Flavors characterization of the parton energy loss study of the transportof heavy quarks in the medium and the hadronization of heavy flavors In ALICE thefocus is placed on the low-momentum region down to zero pT and the reconstructionof heavy-flavor hadrons (mesons and baryons) and the possibility to measure theflavor-dependence in low-momentum jets using light flavor strange and charmedhadrons reconstructed within jets

bull Quarkonia study of the quarkonia dissociation (and possible regeneration) asprobe of the deconfined nature and temperature of the medium In ALICE theemphasis is in the low-momenta region and the possibility to study Jψ ψ(2S) andΥ in central and forward rapidity At forward rapidity in particular the MuonForward Tracker (MFT) will allow the prompt Jψ component to be statisticallyseparated from the displaced production and the ψ(2S) to be observed even inthe most central PbndashPb collisions thanks to a strong reduction of the non-promptbackground

bull Low-Mass Dileptons and Thermal Photons estimation of the initial temper-ature of the medium and investigation of the chiral nature of the phase transitionALICE will access this physics both in the dielectron and dimuon channels down tozero pT

bull Beyond Standard Model specific studies are also undergoing to assess the sen-sitivity of ALICE to the measurement of possible low-mass dark matter bosonsdecaying into electron or muon pairs thanks to the improvement of the discrimina-tion between prompt and non-prompt dileptons

Inner Tracking System (ITS)

The current ALICE Inner Tracking System (ITS) will be totally dismounted at the endof the LHC Run 2 to be replaced by a new detector during Long Shutdown 2 The newITS [72] will be composed of seven cylindrical layers of Monolithic Active Pixel Sensors(MAPS) the innermost one having an internal radius of 224 mm limited by the externalradius of the future beam pipe The internal radius of the outermost layer is 3918 mm

The hit resolution of the detector will be of about 5 microm and the material budget ofthe three innermost layers will be reduced from the present 11 to 03 of the radiationlength per layer these features provide an improvement by a factor about three for thetrack impact parameter resolution in the transverse plane The new ITS would have apseudo-rapidity coverage of |η| lt 122 This upgrade will improve the precision in thesecondary vertex separation (from beauty charm and strange particle decays)

Muon Forward Tracker

The Muon Forward Tracker (MFT) [73] will be a new sub-detector of ALICE made of fivedisks of the same MAPS used in the upgraded ITS The MFT will provide precise track-ing and secondary vertex reconstruction for muon tracks in the pseudo-rapidity regionminus36 lt η lt minus25 within the acceptance of the muon spectrometer

22 A Large Ion Collider Experiment (ALICE) 43

Figure 28 Simulation of low-mass dimuons with and without ALICE upgrade

The measurement of prompt dimuon sources in the low-mass region will strongly ben-efit from the addition of the MFT to the muon spectrometer A significant improvementup to a factor of about 4 is expected for the mass resolution of the narrow resonancesη ω and φ for which resolutions of sim 15 MeVc2 are expected (to be compared withthe current sim 50 MeVc2 resolution at the mass of the φ meson see figure 28) thiswill translate into a significant improvement of the measurements involving these parti-cles allowing at the same time a reliable identification of the underlying thermal dimuoncontinuum and the measurement of the in-medium modified line shape of the short-livedρ meson A precision of about 20 is expected for the observation of these sourcescurrently not feasible due to the very small signal-over-background ratio affecting themeasurement with the present muon spectrometer

TPC

The expected increase of the LHC luminosity after LS2 corresponding to an interactionrate about 50 kHz in PbndashPb implies that TPC operation with a gating grid is no longerpossible This motivates the choice of GEMs for the new readout chambers since theyfeature intrinsic ion blocking capabilities that avoid massive charge accumulation in thedrift volume from back-drifting ions and prevent excessive space-charge distortions Thepresent particle identification (PID) capability via the measurement of the specific ioniza-tion dEdx and the combined momentum resolution of the central barrel tracking systemmust be retained by the TPC upgrade [74] preserving the excellent performance of thecurrent detector

Fast Interaction Trigger (FIT)

The Fast Interaction Trigger (FIT) [75] will be a new sub-detector of ALICE expectedto match and even exceed the functionality and performance (fast event triggering min-imum bias luminosity and charged-particle multiplicity measurements) currently secured

44 Chapter 2 ALICE at the CERN LHC

by three ALICE sub-detectors the T0 the V0 and the FMD detectors The location ofFIT will be similar to that of the current V0 and T0 modules with sensors on both sidesof the Interaction Point (IP) The restrictions imposed by the desired functionality tightspace requirements and the need to minimize the material in the vicinity of the inter-action point have narrowed the choice of detector technologies for FIT to either plasticscintillator- andor Cherenkov radiator

ALICE O2 (ALICE Online-Offline)

After the LHC LS2 the Pb-Pb collision interaction rate will be approximately 50 kHzSince the ALICE physics program will focus on untriggerable signals a continuous read-out will be required in order for all events to be recorded The resulting data throughputfrom the detector has been estimated to be larger than 1 TBs for PbminusPb events roughlytwo orders of magnitude more than in Run 1 and Run 2 To minimize the costs and therequirements of the computing system needed for data processing and storage ALICE isdeveloping a new Computing Framework for Runs 3 and 4 called ALICE Online-Offline(ALICE O2) [76] This framework is designed for a maximal reduction of the data volumeread out from the detector as early as possible during the data-flow

Chapter 3

Data Sample Selection andIntegrated Luminosity Evaluation

Summary31 Data Sample Event and Track Selection 45

32 Integrated Luminosity Evaluation 46

321 F inorm Calculation 47

322 The MB Trigger Cross Section 50

323 Lint Evaluation 51

31 Data Sample Event and Track SelectionThe analysis presented in this thesis is based on a data sample collected by ALICE in2016 in pp collisions at

radics = 13 TeV amounting to asymp 26 times 108 events recorded with

a dimuon trigger This is the largest data sample recorded with the low-pT threshold atsim 05 GeVc as of today (September 2017)

The ALICE data taking is organized into two levels at the first level data are orga-nized into periods each one characterized by the same detector and beam configurationsat the second level data within a given period are further organized into runs each onespanning the interval of two consecutive stops in the data acquisition1 Runs retained forthe analysis are selected on the basis of the quality assurance conditions defined for themuon spectrometer These conditions imply the good operation of all detectors involvedin the analysis of the muon data (muon tracking chambers muon trigger chambers SPDlayers of the ITS V0 and T0) The full list of runs used for the present analysis is reportedin appendix A

The Minimum-Bias (MB) trigger condition for the considered data sample is givenby the logical AND of the signals given by the two V0 detectors (V0AND) [48] Eventscontaining a muon pair are selected by means of a specific dimuon trigger based on thedetection of two muon candidate tracks in the trigger system of the muon spectrometerin coincidence with the MB condition Due to the intrinsic momentum cut imposed bythe detector only muons with pTmicro amp 05 GeVc manage to leave a signal in the triggerchambers Both unlike-sign and like-sign dimuon triggers were collected the like-sign

1 The data acquisition can be stopped either because of beam-related or detector-related issues

46 Chapter 3 Data Sample Selection and Integrated Luminosity Evaluation

trigger sample was downscaled by a factor that varied from run to run according to theinstantaneous luminosity

Background events not coming from beam-beam interactions are rejected by perform-ing an offline selection based on the timing information from the V0 detectors Moreoverit is requested that at least one SPD tracklet contributes to the vertex reconstructed bythe ITS

Track reconstruction in the muon spectrometer is based on a Kalman filter algo-rithm [43 77 78] Muon identification is performed by requiring the candidate track tomatch a track segment in the trigger chambers (trigger tracklet) This request selectsmuons with pTmicro amp 05 GeVc and as a consequence significantly affects the collectedstatistics for dimuons with invariant mass 1 GeVc2 and pT 1 GeVc A harder pro-grammable pT threshold can be imposed on single muons when defining the trigger condi-tions according to the specific physics target it was not the case for the data consideredin the present analysis for which the trigger condition was based on any trigger-matchedmuon Due to the geometrical acceptance of the muon spectrometer the pseudo-rapidityselection minus400 lt ηmicro lt minus250 on the muon tracks is imposed where ηmicro is defined in thelaboratory frame in order to remove the tracks close to the acceptance borders of thespectrometer where the acceptance drops abruptly Muon pairs are built combining twomuon tracks that satisfy the cuts mentioned above

The invariant mass spectrum was obtained both for Opposite-Sign (OS) and Like-Sign (LS) muon pairs the latter being considered for background subtraction relatedpurpose It should be noted that the OS component coming from the LS triggers wassafely neglected in the analysis so that only LS pairs were extracted from the LS-triggeredevents they were upscaled run by run by the inverse of the downscaling factor appliedin the data taking

32 Integrated Luminosity EvaluationThe integrated luminosity for the considered data sample was evaluated as Lint =NMBσMB where NMB is the equivalent number of MB events for the analyzed eventsample and σMB the MB trigger cross section The value of NMB was obtained by usingthe following formula

NMB =sumi=run

F inorm timesN i

MUL (31)

where the N iMUL is the number of events fulfilling the unlike-sign dimuon trigger condi-

tion (MUL given by the presence of at least two tracklets in the muon trigger systemof opposite sign both satisfying the single-muon pT-trigger condition) and F i

norm is thenormalization factor to convert the number of MUL events in the analyzed sample to theequivalent number of MB events In the present analysis two conditions are consideredto estimate the number of MB events

bull The first condition (in the following referred to as ldquoV0rdquo) is theCINT7-B-NOPF-MUFAST one This condition is defined by the coincidence oftwo signals in the V0-A and -C sub-detectors with the requirement that the

32 Integrated Luminosity Evaluation 47

coincidence actually comes from a valid beam-beam interaction (B-NOPF) It is alsorequired that the detectors implied in the definition of the MUL trigger conditionare also included in the readout for the considered M B events this is guaranteedby the composition of the specific MUFAST trigger cluster containing the SPDMUON_TRK MUON_TRG T0 V0 and AD detectors

bull The second condition (in the following referred to as ldquoT0rdquo) is based on the coinci-dence of the above condition CINT7-B-NOPF-MUFAST and the level-0 trigger condition0TVX defined by the coincidence of two signals in the T0-A and -C sub-detectors

321 F inorm Calculation

Three methods are usually considered to compute the Fnorm factor run by run one basedon the counting scaler information (online method) and two based on the reconstructeddata (offline methods)

Pile-Up correction

Regardless of the method one needs to estimate the pile-up contribution in order toproperly correct the estimation of NMB The pile-up correction factor (PU) is defined fora given run i as

PU i = microi

1minus eminusmicroi

microi = minus ln1minus FMBi

purity times L0biMB

Di timesN icolliding times fLHC

where

bull fLHC is the frequency of one bunch in the LHC (11245 Hz)

bull N icolliding is the number of colliding bunches

bull Di is the run duration as given by the Central Trigger Processor (CTP)

bull L0biMB is the scaler input of the level-0 trigger for the considered MB condition

bull FMBipurity is the purity factor associated to the considered MB condition

The purity factor for a generic trigger condition X is computed offline as the fractionof physics-selected (PS) X-trigged events [79] divided by the total number of X-triggedevents

FXipurity = N i

X(PS)N iX(ALL) (32)

In the case of the ldquoT0rdquo MB condition the purity factor is considered equal to 1Figure 31 shows the evolution of the purity factor for all the periods involved in thisanalysis and for the MUL and the ldquoV0rdquo MB trigger conditions

Figure 32 shows the evolution of the pile-up correction factor for the periods involvedin this analysis and for the two conditions considered for the estimate of the number ofMB events

48 Chapter 3 Data Sample Selection and Integrated Luminosity Evaluation

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

0

02

04

06

08

1

Purity factor for MUL

Purity factor for V0 MB condition

B TeyssierWork Thesis

Figure 31 Purity factor for the periods f to p in chronological order

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Pile

-Up

corr

ectio

n fa

ctor

1

105

11

115T0 evaluation

V0 evaluation

B TeyssierWork Thesis

Figure 32 Pile-Up correction for the periods f to p in chronological order

Fnorm Evaluation with Online Method

The online method for the evaluation of the Fnorm factor is based on the information ofthe L0b scaler inputs for the MUL and MB triggers conditions In this case F i

norm iscomputed for a given run i as

F inorm = PU i times FMBi

purity times L0biMB

FMULipurity times L0biMUL

(33)

where FXipurity is the purity factor associated to the events selected by the trigger condition

X This method does exploit the full event sample in the analyzed data The run-by-run

32 Integrated Luminosity Evaluation 49

evolution of the F inorm factor evaluated with this method is given in figure 33 both for

the ldquoV0rdquo and ldquoT0rdquo MB conditions

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Nor

mF

0

2

4

6

310times

method Online V0NormF

method Online T0NormF

B TeyssierWork Thesis

Figure 33 Normalization factor for the periods f to p in chronological order evaluated with theonline method both for the ldquoV0rdquo and ldquoT0rdquo MB conditions

Offline Methods

The offline methods are based on the comparison between the number of minimum biasevents in a given data sample and the number of minimum bias events in the same datasample satisfying at the same time the trigger condition of the analyzed events at thelevel-0 For the first offline method the following formula is used for a given run i

F inorm = PU i times MBi

(MBamp0MUL)i (34)

where

bull MBi is the number of physics-selected MB events

bull (MBamp0MUL)i is the number of physics-selected MB events also fulfilling the MULtrigger condition at the level-0

The run-by-run evolution of the F inorm factor evaluated with this method is given in

figure 34 both for the ldquoV0rdquo and ldquoT0rdquo MB conditionsThe second offline method is based on the formula

F inorm = PU i times MBi

(MBamp0MSL)i timesMSLi

(MSLamp0MUL)i (35)

where

50 Chapter 3 Data Sample Selection and Integrated Luminosity Evaluation

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Nor

mF

0

2

4

6

8

10

12310times

method Offline 1 V0NormF

method Oflline 1 T0NormF

B TeyssierWork Thesis

Figure 34 Normalization factor for the periods f to p in chronological order evaluated with the firstoffline method both for the ldquoV0rdquo and ldquoT0rdquo MB conditions

bull MSLi is the number of physics-selected events satisfying the single-muon triggercondition (MSL given by the presence of at least one tracklet in the muon triggersystem passing the all-pT single-muon threshold) in coincidence with the ldquoV0rdquo MBcondition

bull (MSLamp0MUL)i is the number of physics-selected MSL events (see above) also satis-fying the MUL trigger condition at the level-0

bull (MBamp0MSL)i is the number of physics-selected MB events also satisfying the MSLtrigger condition at the level-0

The run-by-run evolution of the F inorm factor evaluated with this method is given in

figure 35 both for the ldquoV0rdquo and ldquoT0rdquo MB conditionsThe relative rate of the MSL trigger condition relative to the MB and the MUL ones is

larger than the relative rate of the MUL trigger condition to the MB one this guaranteesthis second offline method to profit from a larger event sample resulting in a smallerstatistical uncertainty As expected the results from the two offline methods agree withinthe error bars

322 The MB Trigger Cross SectionThe ldquoMBrdquo cross section σMB was measured with a van der Meer scan for both theldquoV0rdquo and ldquoT0rdquo MB condition and found to be 578plusmn 12 mb for the ldquoV0rdquo conditionand 301plusmn 06 mb for the ldquoT0rdquo condition [80] As reported in [80] ldquowhen the LHC isoperated with isolated-bunch-based filling schemes the two detectors provide indepen-dent measurements of the luminosity with a total uncertainty of 23 When the LHC isoperated with bunch trains the V0-based luminosity is affected by non-trivial systematiceffects in this case the total uncertainty on the luminosity measured with T0 is 34rdquo

32 Integrated Luminosity Evaluation 51

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Nor

mF

0

2

4

6

8

10

12310times

method Offline 2 V0NormF

method Offline 2 T0NormF

B TeyssierWork Thesis

Figure 35 Normalization factor for the periods f to p in chronological order evaluated with thesecond offline method both for the ldquoV0rdquo and ldquoT0rdquo MB conditions

It should be noted that these values refer to the pp data taking of 2015 since thecorresponding results from the van der Meer scan of 2016 (when the data considered inthe present analysis were taken) is not available yet We thus currently assume a 5additional systematic uncertainty on σMB accounting for any possible difference betweenthe efficiency of the detectors involved in the MB trigger conditions between 2015 and2016

323 Lint EvaluationTo obtain the value of Lint for the data taking periods considered in this present analysisone has to assume a reference MB condition and a reference method for the evaluationof Fnorm From equation (31) one can expect that for a given MB condition the valuesof Fnorm coming from the online and offline methods discussed above agree between eachother to give the same estimation of NMB Moreover the definition of the integratedluminosity Lint = NMBσMB implies that the ratio between the NMB(V0) and NMB(T0)and then the ratio between Fnorm(V0) and Fnorm(T0) should be consistent with the ratiobetween σMB(V0) and σMB(T0) As one can see by comparing figures 33 to 35 thethree evaluation methods give compatible estimations for Fnorm However the expectedratio between the ldquoV0rdquo and ldquoT0rdquo estimations of Fnorm is only observed with the onlinemethod For this reason the online method (which also profits from the smaller statisticaluncertainties) is retained for the evaluation of the Lint value to be used for the presentanalysis

The resulting values of Lint are 844plusmn 000(stat)plusmn 042(syst) pbminus1 and904plusmn 000(stat)plusmn 452(syst) pbminus1 respectively when the ldquoT0rdquo and ldquoV0rdquo MBconditions are considered The ldquoT0rdquo MB condition assuring the most stable referenceis finally retained and considered in the present analysis

Chapter 4

Monte Carlo Simulations

Summary41 Light-Meson Decays 53

411 Kinematical Distributions 54412 Dalitz Decays 54413 Two-Body Decays 57

42 Dimuons from Open Heavy-Flavor Decays 60421 PYTHIAndash FONLL Comparison 61422 Decay Chain Length in the Open Heavy-Flavor Processes 62

This thesis work is devoted to the study of light-meson production decaying in two-muon (dimuon) channel The dimuon mass range of interest for this study goes fromthe production threshold (Mmicromicro = 2mmicro) to 15 GeVc2 and is named Low-Mass Region(LMR) This region gives access to the dimuon decays of the light vector (ρ ω and φ)and pseudo-scalar (η and ηprime) mesons discussed in section 41 In addition to these decaysa correlated dimuon continuum is also present in the LMR this contribution is treated insection 42 in terms of open charm and beauty processes

For each process discussed in the following the underlying physics is reviewed andthe main details of the corresponding MC simulations are given All the MC simulationsperformed in this thesis used GEANT3 as transport code

41 Light-Meson DecaysThe properties of the light mesons contributing to the LMR through their dimuon de-cays are reported in table 41 These mesons contribute to the LMR with two types ofdecays the two-body decays and the three-body (Dalitz) decays which will be discussedseparately in the following section All the light-meson decays involved in the LMR aresimulated with the AliGenMUONLMR parametric generator

As can be seen from the quark composition reported in table 41 the ρ and ω mesonscan be used as reference for particle production in the (ud) quark sector while strangenessproduction can be accessed via φ meson (and to a lesser extent η and ηprime mesons)measurement The physical width of the ρ meson significantly larger than one of theother particles contributing to the LMR corresponds to the life time of sim 13 fmc thismakes the ρ an ideal probe of in-medium modifications in the case of QGP productiongiven that a large fraction of the observed ρ mesons would decay inside the hot medium

54 Chapter 4 Monte Carlo Simulations

Particle Pole Mass [MeVc2] Width [MeVc2] Quark Compositionη 547862plusmn 0018 (131plusmn 005) middot 10minus3 1radic

6

(uu + ddminus 2ss

)ρ 77526plusmn 025 1491plusmn 08 1

2

(uuminus dd

)ω 78265plusmn 012 849plusmn 008 1

2

(uu + dd

)ηprime 95778plusmn 006 0198plusmn 0009 1radic

3

(uu + dd + ss

)φ 1019461plusmn 0019 4266plusmn 0031 ss

Table 41 Property of light-mesons involved in the dimuon mass spectrum values taken from [4]

411 Kinematical DistributionsThe kinematics parametrization of the light mesons in the AliGenMUONLMR generator areprovided by a pT-y distribution estimated by PHOJET [81 82] (based on a Dual PartonModel combined with perturbative QCD)

412 Dalitz DecaysAmong the light mesons reported in table 41 the η ω and ηprime mesons give a sizableDalitz decay contribution to the LMR The involved decay channels are summarized intable 42

Process Branching Ratio (BR)ηrarr micro+microminusγ (31plusmn 04) middot 10minus4

ωrarr micro+microminusπ0 (13plusmn 06) middot 10minus4

ηprime rarr micro+microminusγ (108plusmn 027) middot 10minus4

Table 42 Dalitz decay processes in the LMR and the branching ratios used in the analysis

The Feynman diagram corresponding to the Dalitz decay under discussion are shownin figure 41 In the considered processes the parent mesons decay electromagnetically intoone virtual photon with mass M and a third body (real photon or π0) with the virtualphoton converting into a muon pair

η

γlowast

microminus

micro+

γ

1(a) ηrarr micro+microminusγ

ω

γlowast

microminus

micro+

π0

1(b) ωrarr micro+microminusπ0

ηprime

γlowast

microminus

micro+

γ

1(c) ηprime rarr micro+microminusγ

Figure 41 Feynman diagrams of the Dalitz decays of interest for the dimuon LMR

The ALICE muon spectrometer is not equipped for detecting neither the real photonnor the π0 emitted within the Dalitz decays discussed here these decays are identified by

41 Light-Meson Decays 55

]2c [GeV-micro+microM0 01 02 03 04 05 06 07 08

- micro+ micro

MdN

d

0

5

10

15

20

610times (gen)γ-micro+micro rarr η

(a) η

]2c [GeV-micro+microM0 02 04 06 08 1

- micro+ micro

MdN

d

0

2

4

6

610times (gen)0π-micro+micro rarr ω

(b) ω

]2c [GeV-micro+microM0 02 04 06 08 1 12

- micro+ micro

MdN

d

0

1

2

3

4

5610times (gen)γ-micro+micro rarr η

(c) ηprime

Figure 42 Generated dimuon mass distribution of Dalitz decay integrated in full phase space

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

γmicromicrorarrη for -micro+micro)ε times(A

(a) η

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

0πmicromicrorarrω for -micro+micro)ε times(A

(b) ω

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

γmicromicrorarrη for -micro+micro)ε times(A

(c) ηprime

Figure 43 Acceptance times efficiency of Dalitz decay

]2c [GeV-micro+microM0 01 02 03 04 05 06 07 08

- micro+ micro

MdN

d

0

005

01

015

02

610times (rec)γ-micro+micro rarr η

(a) η

]2c [GeV-micro+microM0 02 04 06 08 1

- micro+ micro

MdN

d

0

20

40

60

80

100

310times (rec)0π-micro+micro rarr ω

(b) ω

]2c [GeV-micro+microM0 02 04 06 08 1 12

- micro+ micro

MdN

d

0

20

40

60

80

310times (rec)γ-micro+micro rarr η

(c) ηprime

Figure 44 Reconstructed dimuon mass distribution of Dalitz decay integrated in full phase space

56 Chapter 4 Monte Carlo Simulations

looking at the mass distribution of the dimuons coming from the virtual photon conversionFor this reason it is important to have a theoretical description of the shape of suchmass distributions they can be computed in pure QED under the hypothesis of a point-like electromagnetic transition vertex with the deviation from the real transition vertexquantified by a form factor |F (M2)|2 see Equations (41) to (43)

dΓ (ηrarr micromicroγ)dM = 2M 2

3α

π

Γ (ηrarr γγ)M2

(1minus M2

m2η

)3 (1 +

2m2micro

M2

)

timesradicradicradicradic(1minus 4m2

micro

M2

) ∣∣∣Fη (M2)∣∣∣2

(41)

dΓ (ωrarr micromicroπ0)dM = 2M α

3πΓ (ωrarr γπ0)

M2

(1 +

2m2micro

M2

)radicradicradicradic(1minus 4m2micro

M2

)

times(1 + M2

m2ω minusm2

π0

)2

minus 4m2ωM

2

(m2ω minusm2

π0)2

32 ∣∣∣Fω (M2)∣∣∣2

(42)

dΓ (ηprime rarr micromicroγ)dM = 2M 2

3α

π

Γ (ηprime rarr γγ)M2

(1minus M2

m2ηprime

)3 (1 +

2m2micro

M2

)

timesradicradicradicradic(1minus 4m2

micro

M2

) ∣∣∣Fηprime (M2)∣∣∣2

(43)

where the π0 η ω and ηprime pole masses are taken from the PDG tables [4] and the formfactors are expressed by the pole-parametrization for the η and ω mesons and from aBreit-Wigner form for the ηprime meson∣∣∣Fη (M2

)∣∣∣2 = 1(1minus M2

Λ2η

)2 (44)

∣∣∣Fω (M2)∣∣∣2 = 1(

1minus M2

Λ2ω

)2 (45)

∣∣∣Fηprime (M2)∣∣∣2 = m4

0

(m20 minusM2)2 +m2

0Γ20 (46)

For the η andω form factors the corresponding Λ parameter is taken from a recent analysison p-A NA60 data [83] while for the ηprime form factor the parameters m0 = 0764 GeVc2

and Γ0 = 0102 GeVc2 are extracted from a fit on the Lepton-G data [84] The invariantmass distributions Equations (41) to (43) are implemented in the description of theDalitz decays in the AliGenMUONLMR generator together with the definition of the formfactors Equations (44) to (46) This allows one to extract a properly distributed value ofthe virtual photon invariant mass to be used to simulate the decays ηrarr γlowastγ ωrarr γlowastγ

and ηprime rarr γlowastγ from here the full kinematics of the virtual photon can be extractedallowing in turn the kinematics of the muon pair to be evaluated

41 Light-Meson Decays 57

Figure 42 shows the generated dimuon mass distribution for the three Dalitz decaysof interest here The ηprime mass distribution (figure 42c) shows a characteristic enhancementcorresponding to the ρω peak given by the transition form factor which can be easilyinterpreted in terms of the Vector Meson Dominance model [84] For each decay the pTand y dependence of the product of geometrical acceptance and reconstruction efficiency(A times ε) is shown in figure 43 As expected the phase space coverage at low-pT is moreimportant for the Dalitz decays allowing for larger values of the dimuon invariant massFor the ηrarr micro+microminusγ decay which is the reference process for the extraction of the η-mesonsignal (Atimes ε)micro+microminus is negligible for pT

micromicro 05 GeVc putting a strong constraint in theavailable phase space for the η-meson measurement

Figure 44 shows the reconstructed dimuon mass distribution for each Dalitz decayintegrated over minus400 lt y lt minus250 and 00 lt pT lt 100 GeVc These shapes enter asingredients in the hadronic cocktail fit (discussed in section 52) imposing their profiles tobe sufficiently smooth for each phase space interval considered in the analysis since theseshapes extend over a large mass range and are not easily parameterizable a significantlylarge MC statistics is needed especially when (Atimes ε)micro+microminus is particularly low

413 Two-Body DecaysThe two-body decays of interest for the present thesis work are listed in table 43 withthe corresponding branching ratios For the ω rarr micro+microminus and φ rarr micro+microminus decays thebranching ratios are taken as the average (weighted by the corresponding uncertainty) ofthe available measurements of BR(micro+microminus) and BR(e+eminus) assuming lepton universality inorder to reduce the final uncertainty

Process Branching Ratio (BR)ηrarr micro+microminus (58plusmn 08) middot 10minus6

ρrarr micro+microminus (455plusmn 028) middot 10minus5

aωrarr micro+microminus (728plusmn 014) middot 10minus5

bφrarr micro+microminus (2954plusmn 0030)middot 10minus4

a The value reported in this table for the ω is the weighted average measurement of BR(ωrarr l+lminus)The BR(micro+microminus) is (90plusmn 31) middot 10minus5

b The value reported in this table for the φ is the weighted average measurement of BR(φ rarr l+lminus)The BR(micro+microminus) is (287plusmn 019) middot 10minus4

Table 43 Two-body decay processes in the LMR and the branching ratios used in the analysis

The decay of the vector mesons ρ ω and φ into two muons is mediated by a virtualphoton V rarr γlowast rarr micro+microminus (see figures 45b to 45d) The decay of the pseudo-scalar ηmeson into two muons is a 4th order electromagnetic process (see figure 45a) mediatedby two virtual photons where the micro+ coming from one γlowast and the microminus coming from theother γlowast are contracted

The two-body decays are implemented in the AliGenMUONLMR generator approximatingthe narrow mass line shapes of the η ω and φ mesons with a Dirac delta distributiondefined at the resonance pole mass since their physical widths are negligible with respect

58 Chapter 4 Monte Carlo Simulations

η

γlowast

microminus

γlowast

micro+

1(a) ηrarr micro+microminus

ργlowast

microminus

micro+

1(b) ρrarr micro+microminus

ωγlowast

microminus

micro+

1(c) ωrarr micro+microminus

φγlowast

microminus

micro+

1(d) φrarr micro+microminus

Figure 45 Feynman diagrams of two-body decays of the light neutral meson η ρ ω and φ

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

1

2

3

4

5

610times (gen)-micro+micro rarr ρ

Figure 46 Generated mass distribution for the ρrarr micro+microminus process see equation (47)

to the detector mass resolution On the contrary for the ρ meson due to its natural largemass distribution the following parametrization is used [8385]

dNdM =

α2m4ρ

3 (2π)4

radic1minus 4m2

micro

M2

(1 + 2m2

micro

M2

) (1minus 4m2

π

M2

)32

(m2ρ minusM2

)2+m2

ρΓ2ρ(M)

(2πMT )32 eminusMTρ (47)

with a mass-dependent width

Γρ(M) = Γ0ρmρ

M

M2

4 minusm2micro

m2ρ

4 minusm2micro

32

= Γ0ρmρ

M

(q

q0

)3

(48)

where the Γ0ρ is the full resonance width and mρ the resonance mass pole taken from [4]This distribution is shown in figure 46 one can appreciate the peculiar profile of this lineshape covering practically the whole LMR

For each decay the pT and y dependence of Atimes ε is shown in figure 47 As expectedthe phase space coverage at low-pT becomes larger as the mass of the meson increases

41 Light-Meson Decays 59

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrη for -micro+micro)ε times(A

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrρ for -micro+micro)ε times(A

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrω for -micro+micro)ε times(A

]c [GeVT

p0 2 4 6 8 10

y4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrφ for -micro+micro)ε times(A

Figure 47 Acceptance times efficiency of two body decay

(a) ηrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1

- micro+ micro

MdN

d

0

005

01

015610times (rec)-micro+micro rarr η

(b) ωrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

01

02

03

04

610times (rec)-micro+micro rarr ω

(c) ρrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

002

004

006

008

01

012

610times (rec)-micro+micro rarr ρ

(d) φrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

01

02

03

04

610times (rec)-micro+micro rarr φ

Figure 48 Reconstructed dimuon mass distribution of two body decays integrated in full phasespace

60 Chapter 4 Monte Carlo Simulations

For the ω rarr micro+microminus decay which is the reference process for the extraction of the ω-meson signal (Atimes ε)micro+microminus is significant down to pT = 00 GeVc in the rapidity rangeminus400 lt y lt minus325 and down to pT asymp 20 GeVc towards the y = minus250 limitFor the φ rarr micro+microminus decay from which φ-meson signal can be extracted (Atimes ε)micro+microminus issignificant down to pT = 00 GeVc in the rapidity range minus400 lt y lt minus300 and downto pT asymp 20 GeVc towards the y = minus250 limit

Figure 48 shows the reconstructed dimuon mass distribution for each two-body decayintegrated over minus400 lt y lt minus250 and 00 lt pT lt 100 GeVc These shapes enter to-gether with the Dalitz one discussed in the previous section as ingredients in the hadroniccocktail fit From the mass distributions in figure 48 the detector mass resolution for thenarrow η ω and φ mesons can be estimated performing a Gaussian fit on the centralpart of the peaks the value are found to be ση asymp 458 MeVc2 σω asymp 489 MeVc2 andσφ asymp 520 MeVc2

42 Dimuons from Open Heavy-Flavor DecaysIn the low mass region in addition to the Dalitz and two-body decays of light neutralmesons two other processes may contribute namely the so-called open charm and openbeauty processes In these processes a correlated muon pair comes from the simultaneoussemi-muonic decay of two correlated heavy-flavor hadrons coming from the hadronizationof a heavy qq pair These processes are illustrated in figure 49 for the open charm andbeauty

c

DX

micro

c

D

micro

X

b

BX

micro

b

B

micro

X

Figure 49 Illustration of open heavy-flavor decays

The open charm and beauty processes are generated with the PYTHIA6 MC gener-ator PYTHIA generates the primary cc (or bb) quark pairs performs the correspondinghadronization as well as the decay of the heavy flavor hadrons The decays of the long-livedparticles possibly appearing in the decay chains of the heavy-flavor hadrons are performedby the transport code GEANT3 To save CPU time the PYTHIA6-based parametric gener-ator (AliGenCorrHF) is used developed within the AliRoot framework generating oneheavy-flavor pair per event to further optimize the simulation the first heavy hadronpair is produced in the rapidity hemisphere of the muon spectrometer

The simulation of the open charm and beauty processes depends of the knowledgeof the kinematic distributions of the primary cc (or bb) quark pairs determining the

42 Dimuons from Open Heavy-Flavor Decays 61

kinematics of the first hadron pair and thus the shape of the mass distribution of finalmuon pairs The cc and bb kinematic distributions are known with large uncertainties atforward rapidity at the LHC energies due to the lack of measurements of heavy flavorhadrons in this kinematic range For this reason we also considered a second modelFONLL [86] (for Fixed-Order plus Next-to-Leading Log) giving an alternative descriptionof the cc and bb kinematic distributions based on some perturbative calculation madepossible by the large mass of the charm and beauty quarks To optimize the CPU timefor the simulations based on the FONLL predictions a reweighting is applied on the ex-isting simulations based on the ratio between the (pT minus y) parton distributions given byPYTHIA and FONLL The reweighting has been performed considering three FONLL kinemat-ics distributions the central prediction the prediction corresponding to the upper limitassociated to the uncertainty range and the prediction corresponding to the lower limitassociated to the uncertainty range in this way we can compare up to four hypothesesfor the input of the open charm and beauty processes

The discussion presented in the following section applies to the open charm processas well as to the open beauty one similarly each figure will include two panels the ldquoardquoone dedicated for the open charm case the ldquobrdquo for the beauty case

421 PYTHIAndash FONLL ComparisonTo estimate the difference between the available hypotheses on the input parton kinemat-ics the ratio of the FONLL partonic pT distributions (corresponding to the central valueand the upper-lower limits of the uncertainty range) to the PYTHIA one is shown in Fig-ure 410 In this figure the ratio corresponding to FONLL central value is represented insolid curve and the ratios corresponding to the upper and lower limits of FONLL uncertaintyrange are represented as an uncertainty band As can one see the ratio of the centralFONLL value to PYTHIA deviates significantly from unity the deviation becomes strongerwhen the upper-lower limits of the FONLL prediction are considered The PYTHIA-FONLLdisagreement is stronger for the charm than for the beauty

It is now interesting to investigate how the difference between the PYTHIA and FONLLpredictions for the input kinematic distributions of the cc and bb quark pairs affects theshape of the reconstructed dimuon mass spectra which will be used as ingredients ofthe fit of the data To do so the reconstructed mass spectra corresponding to the fouravailable MC inputs are compared in figure 411 PYTHIA FONLL central value FONLLupper value and FONLL lower value For the sake of comparison the four distributionsare normalized to the same integral In the case of the open charm process figure 411athe differences between the models are clearly visible accross the considered mass rangewhile for the open beauty process figure 411b there is a remarkable agreement betweenthe curves A possible way to quantify the uncertainty on reconstructed dimuon massdistributions of open charm and beauty due to the model assumed for the input partonicdistribution is to evaluate the FONLL over PYTHIA ratios as a function of the dimuon massas shown in figure 412

As expected the ratios for the open beauty process stay significantly closer to unitythan the open charm process By inspecting the graphs one can estimate the uncertaintyon the open charm shape to be of the order of 15 in the LMR significantly increasing

62 Chapter 4 Monte Carlo Simulations

]c [GeVT

p0 2 4 6 8 10

ratio

FO

NLL

Pyh

tia fr

om C

harm

0

1

2

3

(a) charm

]c [GeVT

p0 2 4 6 8 10

ratio

FO

NLL

Pyh

tia fr

om B

eaut

y

0

1

2

3

(b) beauty

Figure 410 Partonic pT distribution ratio FONLL [87] over PYTHIA the black curve represents thereference value of the ratio and the red hatching represents the error according to FONLL model

]2c [GeV-micro+microM0 1 2 3 4 5

au

0

10

20

30

40

50

3minus10times

FONLL

PYTHIA

FONLL - max

FONLL - min

(a) open charm

]2c [GeV-micro+microM0 1 2 3 4 5

au

0

10

20

30

40

3minus10timesFONLL

PYTHIA

FONLL - max

FONLL - min

(b) open beauty

Figure 411 Reconstructed dimuon mass coming from open heavy flavor semi-leptonic decays

towards large masses while from the open beauty shape the uncertainty in the LMR stayswithin 5 We will come back to these uncertainties in section 52 where the fit routineallowing the signal extraction will be discussed

422 Decay Chain Length in the Open Heavy-Flavor Processes

In the open heavy-flavor processes considered in this section the number of decay stepsbetween the initial parton and the final muon (noted decay chain afterwards) can bepotentially large resulting in a weakening of the kinematic correlation between the initialand the final states If the decay chains associated to the two final muons are sufficiently

42 Dimuons from Open Heavy-Flavor Decays 63

]2c [GeV-micro+microM0 1 2 3 4 5

0

02

04

06

08

1

12

14

FONLL over Pythia

FONLL - Min over Pythia

FONLL - Max over Pythia

(a) open charm

]2c [GeV-micro+microM0 1 2 3 4 5

09

095

1

105

FONLL over Pythia

FONLL - Min over Pythia

FONLL - Max over Pythia

(b) open beauty

Figure 412 Dimuon mass spectrum ratio from FONLL (reference min and max value) over PYTHIA

long the initial qq correlation could be substantially washed out in the final muon pairFor this reason it is interesting to study the distribution of the decay chain length (λmicro)in simulated open charm and beauty processes defined as the number of decay stepsbetween the initial parton and the final muon

-microlength 0 2 4 6 8 10

+ microle

ngth

0

2

4

6

8

10

1

10

210

310

410

510

(a) open charm

-microlength 0 2 4 6 8 10

+ microle

ngth

0

2

4

6

8

10

1

10

210

310

410

510

(b) open beauty

Figure 413 micro-chain for open heavy flavor at generated level

In figure 413 the correlation between the λmicro of the positive and negative muons isshown for the dimuons coming from the open charm and beauty simulations In thisfigure on can clearly see that λmicro can get as large as 10 As expected the average λmicrovalues are larger for the open beauty process than the open charm one due to the largerphase space available

Since the λmicro distributions extend over relatively large ranges one can wonder which isthe impact of having short or long muon decay chains on the shape of the dimuon invariant

64 Chapter 4 Monte Carlo Simulations

]2c [GeV-micro+microM0 1 2 3 4 5

au

4minus10

3minus10

2minus10

1minus10

4le plusmnmicroλ = 4 amp plusmnmicroλ 3le plusmnmicroλ = 3 amp plusmnmicroλ 2le plusmnmicroλ = 2 amp plusmnmicroλ 1le plusmnmicroλ = 1 amp plusmnmicroλ

(a) open charm

]2 [GeVc-micro+microM0 1 2 3 4 5

au

4minus10

3minus10

2minus10

1minus10

4le plusmnmicroλ = 4 amp plusmnmicroλ 3le plusmnmicroλ = 3 amp plusmnmicroλ 2le plusmnmicroλ = 2 amp plusmnmicroλ 1le plusmnmicroλ = 1 amp plusmnmicroλ

(b) open beauty

Figure 414 Generated dimuon mass coming from open heavy flavor semi-leptonic decays withparticular λmicro

mass distributions To do so in figure 414 the dimuon mass distributions are shown forfour particular λmicro+λmicrominus combinations As expected shorter decay chains correspond toharder mass distributions

We thus verified that the shape of the invariant mass profile of the open charm andbeauty dimuons depends of the length of the decay chains of the two muons This meansthat to properly reproduce the dimuon mass profile of the open charm and beauty com-ponents in the data we have to correctly reproduce the distribution of the decay lengthchains for the simulated dimuons Now this is not a problem as long as any dimuon froman open charm or beauty process is retained both in the data and in the MC Howeverthe data considered for the signal extraction are obtained by subtracting the combinato-rial background from the raw dimuon spectrum implying that we should retain in theMC the correlated dimuons only But the correlation of a muon pair coming from anopen charm or beauty process is progressively lost as the length of the decay chains of thetwo muons increases and it is extremely hard mdash in terms of analysis strategy and CPUtime mdash to estimate and take such an effect into account in the MC simulations Thisintroduces a source of uncertainty when describing the correlated continuum in the datawith the superposition of the open charm and beauty simulations

Chapter 5

Signal Extraction

Summary51 Combinatorial Background Evaluation and Subtraction 65

511 The Event Mixing Technique 66

512 Monte Carlo Validation of the Event Mixing Technique 67

513 The Combinatorial Background Estimation 68

52 Invariant Mass Fit Procedure 70

521 Specific Constraints on the Hadronic Cocktail Components 71

522 Correlated Continuum Treatment 72

523 A Few Examples of Hadronic Cocktail Fits 76

In this chapter the main source of background for the dimuon decay channel will bediscussed as well as the strategy considered for the extraction of the signals of interestFrom now on following a convention widely used within the ALICE muon communityrapidity values are given in the positive axis justified by the symmetry of the pp collisionsystem with respect to y = 0

51 Combinatorial Background Evaluation and Sub-traction

The present analysis is based on the study of the OS dimuon invariant mass spectrumDimuons are built by combining muon pairs coming from the same event (see section 31)Since dimuons coming from the light-neutral meson decays of interest for this work cannotbe disentangled from the other dimuon sources any pair of muons must be consideredwhen building the dimuon invariant mass spectrum This implies that a fraction of theconsidered dimuons actually comes from randomly paired uncorrelated muons this frac-tion of dimuons is conventionally named ldquocombinatorial backgroundrdquo The ratio betweenthe correlated and uncorrelated dimuon components varies significantly according to thecollision system the considered mass region and the apparatus performance In the low-mass region the ALICE muon spectrometer gives correlated over uncorrelated dimuonratios as large as few units (in pp collisions) and as low as few percents (in the mostcentral Pb-Pb collisions)

66 Chapter 5 Signal Extraction

511 The Event Mixing TechniqueThe combinatorial background for the OS dimuons has been evaluated using an eventmixing technique based on the reasonable assumption that the LS dimuon sample doesnot contain correlated muon pairs The mixing event technique implies the creation of asample of uncorrelated dimuon formed by pairing two muons coming from two differentevents In the following we will identify dimuons built from a same event with the labelldquodirrdquo and dimuons built from different events with the label ldquomixrdquo The event mixingtechnique is illustrated in figure 51

Event A

micro+A1

microminusA2

Event B

microminusB1

microminusB2

micro+B3

Opposite Signmicro+A1micro

minusB1

micro+A1micro

minusB2

microminusA2micro+B3

Like Sign ++micro+A1micro

+B3

Like Sign minusminusmicrominusA2micro

minusB1

microminusA2microminusB2

Figure 51 Illustration of mixing events with two events one with two muons and one with threemuons

The mixed OS dimuon sample is used in the event mixing technique to estimatethe OS combinatorial background in the direct OS dimuon sample for this reason onlyevents sharing same global properties are considered in the event mixing Among theseglobal properties one can cite the z-position of the primary vertex the charged-particlemultiplicity or in nucleus-nucleus collisions the orientation of the event plane In the ppcollisions considered in the present analysis the impact of classifying the events accordingto the z-position of the primary vertex and the charged-particle multiplicity was testedresulting in no difference with respect to the case in which the events are mixed regardlessof their global properties1

The shape of the invariant mass distribution expected for the OS uncorrelated dimuonsis taken for each kinematic range considered in the analysis directly from the outputdistribution Nmix

+minus (M) given by the event mixing technique The normalization is fixed tothe integral of the distribution 2R(M)

radicNdir

++(M) middotNdirminusminus(M) extracted from the data

Nmix+minus (M) minusrarr Nmix

+minus (M)

int2R(M)

radicNdir

++(M) middotNdirminusminus(M) dMint

Nmix+minus (M) dM

(51)

The integral of the 2R(M)radicNdir

++(M) middotNdirminusminus(M) distribution is indeed a good estimation

of the total number of the OS dimuons in the data as long as the LS dimuon samples1 This is valid as long as the analysis is integrated over the mentioned global properties in particular

the charged-particle multiplicity

51 Combinatorial Background Evaluation and Subtraction 67

Ndir++ and Ndir

minusminus do not contain any correlated muon pair The R factor accounts for thepossible differences between the acceptances of ++ minusminus and +minus muon pairs

R(M) = A+minus(M)2radicA++(M) middotAminusminus(M)

(52)

The R factor was estimated as

R(M) = Nmix+minus (M)

2radicNmix

++ (M) middotNmixminusminus (M)

(53)

where Nmix++ and Nmix

minusminus is the number of dimuons for the given sign combination theacceptances are evaluated with the mixing

512 Monte Carlo Validation of the Event Mixing TechniqueA Monte Carlo approach was considered to check the quality of the combinatorial back-ground estimation as follows Events containing two muons were simulated with thekinematics extracted randomly and independently for the two muons from some pT andy distributions taken from the data The azimuthal angle of each muon was randomlydrawn within flat distribution and the charges also randomly attributed In this waythe OS sample of the direct dimuons from this MC event sample could be assumed to bepurely combinatorial by construction We could thus check if the procedure describedabove was able to reproduce its mass shape and normalisation To do this we appliedto this same MC sample the event mixing technique to obtain the mass shape with thecorrect normalization

The ratio RMCdirmix between the true and estimated mass shapes of the combinatorial

OS dimuons was thus extracted for each kinematics interval considered in the analysisSeveral options are possible for the trigger class of the events considered in the eventmixing procedure The considered trigger classes are based on the ldquoV0rdquo trigger conditionsee section 31 to which a specific condition is added based on the response of the muontrigger

bull ldquoMULrdquo based on the presence of at least two tracklets in the muon trigger systemof opposite sign both passing the low-pT single-muon threshold

bull ldquoMLLrdquo based on the presence of at least two tracklets in the muon trigger systemof like sign both passing the low-pT single-muon threshold

bull ldquoMSLrdquo based on the presence of at least one tracklet in the muon trigger systempassing the low-pT single-muon threshold

bull ldquoMSL-onlyrdquo it is defined by this logical combination of trigger conditionsMSL ampMUL ampMLL so it is the condition which minimizes the impact of the dimuontrigger condition on the retained events

The trigger condition of the events considered for the event mixing technique waschosen as the one maximizing the flatness of RMC

dirmix Figures 52 and 53 show that the

68 Chapter 5 Signal Extraction

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeVmicromicroM

0 1 2 3 4 5 6

Dir

ect

Mix

ed

06

08

1

12

14

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

lt 40y25 lt

c lt 100 GeVT

p00 lt = 13 TeVsALICE pp

MUL

MLL

MSL

Figure 52 Comparison of background evalua-tion ratio direct over mixed for ldquoMULrdquo ldquoMLLrdquoand ldquoMSLrdquo conditions

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeVmicromicroM

0 05 1 15 2 25 3

Dir

ect

Mix

ed

09

095

1

105

11

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

MSL

MSL amp MUL amp MLL

Figure 53 Comparison of background evalu-ation ratio direct over mixed for ldquoMSLrdquo andldquoMSL-onlyrdquo conditions

best results are obtained considering events satisfying the ldquoMSL-onlyrdquo condition withldquoMSLrdquo condition also giving a reasonably small deviation of RMC

dirmix from unity On thecontrary the worst performance is associated to the MLL and MUL trigger conditions

The combinatorial background mass shape evaluated for the real data was correctedfor the RMC

dirmix ratio To get rid of the statistical fluctuations due to the limited availableMC sample this ratio is parametrized by the following function before being used tocorrect the data

f(M) = A eminusaM minusB eminusbM +C (54)

where all the parameters are imposed to be positive except C This correction is performedindependently in each (pT y) phase space interval considered in the analysis

513 The Combinatorial Background Estimation

Having validated the method for the evaluation of the combinatorial background it is nowpossible to use it for isolating the dimuon correlated signal in the data Following the resultof the MC validated presented in the previous section the ldquoMSL-onlyrdquo events are used asinput for the event mixing technique The typical mass dependence of the R-factor (ratiobetween the acceptance of LS and OS muon pairs) defined in equation (52) and estimatedas equation (53) is shown in figure 54 for the phase space interval 10 lt pT lt 100 GeVcand minus400 lt y lt minus250 In this same kinematics interval the comparison between theraw dimuon and the combinatorial background is shown in figure 55 The correspondingisolated dimuon correlated signal is shown in figure 56 forMmicromicro lt 100 GeVc2 where thepeaks of the Υ(1S) ψ(2S) and Jψ resonances can be observed and in figure 57 for thelow-mass region where the peaks of the φ and ρω two-body decays are visible togetherwith the structure of the η Dalitz decay

51 Combinatorial Background Evaluation and Subtraction 69

]2c [GeVmicromicroM0 2 4 6 8 10

R

0

02

04

06

08

1

12

lt 1000T

p100 lt

lt - 250y- 400 lt

B TeyssierWork Thesis

Figure 54 The R factor for the data integratedin 10 lt pT lt 100 GeVcand minus400 lt y lt minus250

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 2 4 6 8 10

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

dNd

M

210

310

410

510

610

raw mass spectrum

mass spectrummixOS

B TeyssierWork Thesis

Figure 55 Raw data between 250 lt y lt 400and 10 lt pT lt 100 GeVc

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeVmicromicroM0 2 4 6 8 10

]2 c [d

imuo

ns p

er 2

5 M

eV

micromicrodN

dM

210

310

410

510

610 B TeyssierWork Thesis

Jψ

ψ (2S)

Υ (1S)

Figure 56 Signal after subtraction of combina-torial background in mass range between 02 to100 GeVc2

0 02 04 06 08 1 12 140

01

02

03

04

05

610timesB Teyssier

Work Thesis

ρω

φ

Figure 57 Signal after subtraction of combina-torial background in mass range between 02 to15 GeVc2

70 Chapter 5 Signal Extraction

The combinatorial background estimation and subtraction is particularly challengingat very low pT where the signal-over-background ratio is smaller (as small as asymp 1 at theφ peak) In order to appreciate how the signal can nevertheless be extracted down tovery low pT in figure 58 (top panels) the raw data with the associated combinatorialbackground are shown for 00 lt pT lt 02 GeVc in the rapidity intervals where theacceptance is non-negligible (the most forward region see figures 43 and 47) Thecorresponding isolated signal is shown in the same figure (bottom panels)

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

25310times

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 375 lt y lt 400

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15310times

B TeyssierWork Thesis

(e) 350 lt y lt 375

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310timesB Teyssier

Work Thesis

(f) 375 lt y lt 400

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310timesB Teyssier

Work Thesis

Figure 58 Rapidity evolution of signal and combinatorial background shapes for 00 lt pT lt

02 GeVc

52 Invariant Mass Fit ProcedureAfter subtraction of the uncorrelated background the next step in the analysis is theextraction of the signals of interest from the dimuon correlated invariant mass spectrumin this specific case this means counting how many dimuons from the η rarr micro+microminusγω rarr micro+microminus and φ rarr micro+microminus decays can be extracted from the data for each of the pT-yintervals considered in the analysis For this step the dimuon correlated invariant massspectrum is decomposed into the expected sources composing the hadronic cocktail (two-body and Dalitz decays of light neutral mesons see section 41) via a fit procedure also

52 Invariant Mass Fit Procedure 71

including a description of the correlated continuum component

521 Specific Constraints on the Hadronic Cocktail Compo-nents

In the fit procedure considered in this analysis for the extraction of the signals of interestspecific constraints have been imposed to the components of the hadronic cocktail inorder to reduce the number of degrees of freedom fixing the minor processes (in terms ofreconstructed dimuons) to the major ones Each considered constraint has been also takenas a contribution in the evaluation of the systematics on the signal extraction discussedin section 61

Fixing the relative branching ratios of two-body and Dalitz decays for the ηand ω meson mdash The η and ω mesons contribute to the hadronic cocktail with twodecay channels ηrarr micro+microminusγ and ηrarr micro+microminus for the η and ωrarr micro+microminusπ0 and ωrarr micro+microminus

for the ω Since the branching ratios of each channel is known from the literature thenormalizations of the two-body and Dalitz decay modes can be fixed to each other (as longas the quality of the data does not allow for an independent measurement of the relativebranching ratios) This constraint has been technically implemented for the η meson byconsidering the normalization of the ηrarr micro+microminusγ process has a free parameter and fixingthe ηrarr micro+microminus contribution to it for the ω meson the normalization of the ωrarr micro+microminus

process has been left as a free parameter the contribution of the ω rarr micro+microminusπ0 decaybeing fixed to it For each particle the process associated to the free parameter is the onemore clearly identifiable in the invariant mass profile of the data The relevant branchingratios are listed in tables 42 and 43

Fixing the σηprimeσφ cross-section ratio mdash The contribution of the ηprime Dalitz decayaccounts for a very small fraction of the total reconstructed dimuon mass spectrum forthis reason and because of its continuum shape having no dominant structure apart fromthe broad peak at ρ mass (due to the contribution of the ρ meson to the ηprime form factorsee section 412) the fit procedure is not sensitive to this contribution Consequently thenormalization of the ηprime rarr micro+microminusγ process has been set by fixing the ηprime cross-section tothe cross-section of one of the particles giving a major contribution to the invariant massspectrum namely the φ meson The reference value for the σηprimeσφ cross-section ratio hasbeen evaluated with PHOJET to be 3151 in the rapidity window 25 lt y lt 40 integratedover pT This ratio has been rescaled in each pT-y interval considered in the analysisaccording to the kinematic distributions of the two particles also given by PHOJET

Fixing the σρσω cross-section ratio mdash Due to the broad line shape of the ρ mesonand the limited mass resolution of the detector for the superimposed ω rarr micro+microminus peakthe ρ rarr micro+microminus contribution cannot be easily disentangled in the fit procedure For thisreason the normalization of the ρrarr micro+microminus contribution has been set to the ωrarr micro+microminus

one by fixing the σρσω cross-section ratio The reference value for this ratio has beentaken as 10 from previous measurements [88ndash90]

72 Chapter 5 Signal Extraction

Due to the mass resolution of the ω peak the distinction of the ω and ρ two-bodycontribution is not obvious So it is better to enslave the ρ two-body component to theω to increase the stability of the fit The ratio of the production cross-section of ρω ismeasured to 10 in several previous experiments [88ndash90]

522 Correlated Continuum TreatmentSeveral choices can be considered for the description of the correlated continuum as dis-cussed below As discussed in section 42 the main sources in the correlated dimuoncontinuum are the open charm and beauty processes However as also discussed in sec-tion 42 the evaluation of the MC template of the invariant mass shape of the open charmand beauty dimuons is affected by potentially non-negligible uncertainties according tothe considered input for the cc and bb kinematics and the real degree of correlation of thefinal state muons Moreover one as to consider the possibility of having some residualuncertainty from the combinatorial background subtraction and a possible dimuon com-ponent from correlated light-flavor hadron decays On the basis of these considerationstwo approaches have been tested for the description of the correlated continuum

In the fit process for treating the underlying physics continuum we assume that themain source of this continuum is based on the open heavy-flavor where the way to obtainthe shapes of open charm and beauty are described in section 42 Two possible ways forusing these shapes in the fit process one based on the full description of all processes theother based on a phenomenological approach for the correlated continuum and realisticdescription of processes are considered

The ldquocharm+beautyrdquo approach mdash This approach is based on three assumptions

1 The correlated continuum has only two components open charm and beauty

2 The shapes of the dimuon invariant mass templates for the open charm and beautyprocesses are known with negligible uncertainties (with the same precision as thetemplates for the hadronic cocktail processes)

3 The ratio between the open beauty and the open charm dimuon components isknown (together with its pT and y dependence at the specific energy considered inthe analysis) either from measurements or from tuned models like FONLL or PYTHIA

In this approach the correlated continuum description is associated to one free parameterThe only available measurements for the cc and bb cross-section at forward rapidity comefrom LHCb [3891ndash93] the ratio σbbσcc is (594plusmn 055) middot 10minus2 in good agreement withthe central value of the FONLL prediction (645 middot 10minus2) [86 87]

When considering this approach in the description of the correlated continuum non-negligible tensions between data and MC can be found according to the specific phasespace interval considered These tensions increase towards mid-rapidity while are almostnegligible for the most forward rapidity intervals An example is given in the left-columnplots of figures 59 and 510 where the data-MC comparison is shown for the six y intervals

52 Invariant Mass Fit Procedure 73

considered for the analysis in the pT interval 20 lt pT lt 22 GeVc The same trend isobserved in almost all the considered pT intervals

As a matter of fact these tensions induce an indirect bias on the extraction ofthe signals of interest for the analysis particularly important for the extraction of theω rarr micro+microminus signal For this reason this approach is probably not well-fitted for thisspecific analysis aiming to simultaneously extract the η rarr micro+microminusγ ω rarr micro+microminus andφrarr micro+microminus signals

The semi-empirical approach mdash This new approach has been developed after con-sidering the major limitations of the ldquocharm+beautyrdquo approach in describing the dataover the full rapidity interval available The main difference with respect to the previousapproach is the fact that we abandon any strict physical interpretation of the correlatedcontinuum describing it with an empirical profile flexible enough to saturate the tensionbetween data and MC ensuring a robust extraction of the signals of interest for the anal-ysis This is achieved by describing the correlated continuum by means of two (or more)free parameters each controlling the normalization of an independent empirical shapeThe specific shape of these independent components is not really important still one hasto use sufficiently different mass shapes to ensure enough freedom on the total profile ofthe continuum

Two variants of this semi-empirical approach have been tested in this analysis

bull A 2-component description of the correlated continuum In this case an obviouschoice is to take the two components as the invariant mass distributions of OSdimuons from open charm and open beauty simulations2 This choice allows one tocombine the required smoothness of the continuum invariant mass shape with thekinematical constraints typical of a reconstructed dimuon mass distribution closeto the low-mass threshold this would not have been (easily) achievable with anytrivial combination of analytical parametric functions

bull A 3-component description of the correlated continuum In this variant we add athird component to the two components already considered in the previous case areasonable choice is to take this third component to have the profile of the combi-natorial background evaluated in each pT and y interval considered in the analysis

The results of the data description with these two variants of the semi-empirical ap-proach are shown in figures 59 and 510 in the center and right panels respectively forthe 2- and the 3-component description of the correlated continuum As one can see the2-component description already fixes the tension between data and MC found with theldquocharm+beautyrdquo approach in the full y range Nevertheless the addition of the third de-gree of freedom allowed by the 3-component description of the correlated continuum stillimproves the extraction of the signal in some specific cases see for instance the extractionof the φrarr micro+microminus signal in figures 59b and 59c For this reason the 3-component variantof the semi-empirical approach has been retained as the reference method for the signalextraction for the present analysis

2 It should be clear that in this semi-empirical approach the physical interpretation of any of the twocomponents taken separately is meaningless and must be avoided

74 Chapter 5 Signal Extraction

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 275y250 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 275y250 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 275y250 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 300y275 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 300y275 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 300y275 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(g) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(h) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(i) 300 lt y lt 325

Figure 59 Signal fit for 20 lt pT lt 22 GeVc and various y intervals The first figure of each linecorresponding to the method with the full description of processes the second and third figures ofeach line corresponding to the hybrid method with two or three components respectively

52 Invariant Mass Fit Procedure 75

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6310times

lt 400y375 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(g) 375 lt y lt 400

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6310times

lt 400y375 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(h) 375 lt y lt 400

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6310times

lt 400y375 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(i) 375 lt y lt 400

Figure 510 Signal fit for 20 lt pT lt 22 GeVc and various y intervals The first figure of eachline corresponding to the method with the full description of processes the second and third figuresof each line corresponding to the hybrid method with two or three components respectively

76 Chapter 5 Signal Extraction

523 A Few Examples of Hadronic Cocktail FitsThe detailed breakdown of the MC sources involved in the fit procedure is shown infigure 511 where the data sample considered in the present analysis is integrated over250 lt y lt 400 and 10 lt pT lt 100 GeVc The structures of the η rarr micro+microminusγω rarr micro+microminus and φ rarr micro+microminus processes considered for the estimation of the η ω and φyields are observed to shine out over the underlying continuum Here as well as in thefits presented in the rest of the document the red profile is the sum of the MC sourcesThe uncertainty on the total MC profile is evaluated by combining the uncertainties onthe normalization of each considered source For the processes whose normalization isleft free in the fit this uncertainty is the statistical one resulting from the fit procedureitself for the other processes we propagate the systematic uncertainty on the parameters(branching ratios or cross section ratios) which fix their normalizations to those of thefree processes

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

01

02

03

04

05

610times

γmicromicro

rarrη

γmicromicrorarrη

micromicrorarrη

micromicrorarrρ0πmicromicrorarrω

micromicrorarr

ω

micromicrorarrφ

continuumcorrelated

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

lt 400y250 lt

c lt 1000 GeVT

p100 lt = 13 TeVsALICE pp

lt 40y25 lt

c lt 100 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y250 lt

c lt 1000 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 40y25 lt

c lt 100 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y250 lt

c lt 1000 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

Figure 511 Example of hadronic fit in 250 lt y lt 400 and 10 lt pT lt 100 GeVc

The shape of the dimuon invariant mass spectrum changes significantly according tothe considered pT-y interval In particular at very low-pT and towards central rapiditythe acceptance constraints imposed by the detector deplete the mass spectrum near thekinematic threshold For this reason some of the processes are not measurable in specificregions of the phase space as it could be expected by inspecting the pT-y profiles of the(Atimes ε) reported in figures 43 and 47 In addition at high-pT one observes a decrease ofthe ratio of the hadronic cocktail over the correlated continuum which could be attributedto the decrease of the ratio of the light flavor sources (composing the hadronic cocktail)over the heavy flavor ones (contributing to the correlated continuum) The full evolutionof the dimuon invariant mass spectrum profile as a function of pT and y can be appreciated

52 Invariant Mass Fit Procedure 77

by considering the plots in appendix C In figure 512 we report a few examples illustratingthe discussed point

(a) 00 lt pT lt 02 GeVcand 375 lt y lt 400

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 04 lt pT lt 05 GeVcand 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 20 lt pT lt 22 GeVcand 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

310times

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 40 lt pT lt 45 GeVcand 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 70 lt pT lt 80 GeVcand 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 80 lt pT lt 100 GeVcand 250 lt y lt 275

Figure 512 A few examples of hadronic fit in several pT and y intervals

Chapter 6

Systematics Evaluation

Summary61 Systematics on the Signal Extraction 80

611 Relative Branching Ratio of two-body and Dalitz Decays for the ηand ω Mesons 80

612 σηprimeσφ Cross-Section Ratio 80

613 σρσω Cross-Section Ratio 81

614 Upper limit of the fit 81

615 The correlated continuum shape 81

616 Systematic Uncertainty Computation 82

62 Systematics from the MC input 82

63 Systematics on Trigger Efficiency 83

631 Evaluation of the Trigger Response Function 83

632 Results 84

64 Systematics on Tracking Efficiency 85

641 Preliminary Check 85

642 Tracking Efficiency Evaluation 86

643 MC parametrization 88

644 Results 89

65 Summary of Systematic Uncertainty 89

In this chapter all the systematics sources of the present analysis are presented Twomain groups of systematics uncertainties have been studied

bull the sources contributing to the systematics uncertainty on the signal extraction

bull the sources contributing to the systematics on the (Atimes ε) evaluation

In the first group we include the uncertainties on the parameters involved in thefit procedure (see section 52) relative branching ratios cross-section ratios correlatedcontinuum shape fit range In the second group we include the uncertainties on thekinematic input of the MC simulations on the tracking efficiency and the trigger response

80 Chapter 6 Systematics Evaluation

61 Systematics on the Signal ExtractionIn order to define the systematics tests on the signal extraction a reference scenario hasbeen defined based on the reference values of the parameters involved in the fit procedureFor each parameter one or more alternative values have been considered each systematictest is defined by the variation of one parameter only while the others are kept fixedto their reference value In total 10 systematic tests have been considered the totalsystematic uncertainty on the number of η rarr micro+microminusγ ω rarr micro+microminus and φ rarr micro+microminus

dimuons was taken as the standard deviation of the values resulting from these tests

Syst test reference value alternative value(s)BR ηrarr micro+microminus PDG PDG minus1σ PDG +1σBR ωrarr micro+microminusπ0 PDG PDG minus1σ PDG +1σRatio σηprimeση 0295 minus50 +50Ratio σρσω 10 minus10 +10Upper fit limits 15 GeVc2 20 GeVc2

Templates for thecorrelated contin-uum components

ccrarr micromicro from PYTHIAbbrarr micromicro from PYTHIA

OS from evt mix (data)

ccrarr micromicro from FONLLbbrarr micromicro from FONLL

OS from combinatorial bkg (MC)

Table 61 Summary of systematics tests

611 Relative Branching Ratio of two-body and Dalitz Decaysfor the η and ω Mesons

This systematics test reflects the uncertainty on the ratio between the branching ratio ofthe two-body and Dalitz decay channel of the η and ω mesons In this analysis this testwas implemented by varying the branching ratio of the η rarr micro+microminus and ω rarr micro+microminusπ0

processes by plusmn1σ where σ is the uncertainty on the measurement reported by the PDG(shown in tables 42 and 43) resulting in four independent alternative fits on the data

The variation of the ηrarr micro+microminus branching ratio was found to have a negligible impacton the extraction of η rarr micro+microminusγ and φ rarr micro+microminus signals and a limited impact on theextraction of the ωrarr micro+microminus signal of the order of 1 On the contrary the variation oftheωrarr micro+microminusπ0 branching ratio by plusmn1σ has an average impact of plusmn3 for the extractionof ηrarr micro+microminusγ and ωrarr micro+microminus signals and negligible for the φrarr micro+microminus signals

612 σηprimeσφ Cross-Section Ratio

The ratio σηprimeσφ was varied by plusmn50 to take into account the general lack of mea-surements for this ratio and the differences between the predictions from the availablephenomenological models PYTHIA6 and PHOJET The impact of the considered plusmn50 vari-ation has been observed to be in average ∓2 for the ωrarr micro+microminus signal and negligiblefor the φrarr micro+microminus and ηrarr micro+microminusγ signal

61 Systematics on the Signal Extraction 81

613 σρσω Cross-Section RatioThe uncertainty on the σρσω ratio has been taken from the existing measurements atlower energy [88ndash90] The absence of any strong theoretical argument in favor of animportant energy dependence of this ratio allowed us to take a plusmn10 for the associateduncertainty As expected the impact of this plusmn10 variation is non-negligible only for theextraction of theωrarr micro+microminus signal which is affected by a corresponding ∓2 uncertainty

614 Upper limit of the fitThe lower limit of the invariant mass fit range has been set to the 2mmicro kinematic thresholdin order to be sensitive to the full structure of the η rarr micro+microminusγ decay For the upperlimit a reference value has been set at 15 GeVc2 this value is a trade-off betweenbeing sensitive to the full width of the φ rarr micro+microminus peak and limiting the impact of thecontinuum region between the φ and Jψ resonance where no signal of interest for thelight-neutral mesons can be extracted To study the systematic uncertainty linked to thechoice of the upper limit of the fit range an alternative value has also been defined at20 GeVc2 The corresponding average impact on the extraction of the signals of interestis -3 -12 and -4 respectively for the η rarr micro+microminusγ ω rarr micro+microminus and φ rarr micro+microminus

signals

615 The correlated continuum shape

]2c [GeVmicromicroM0 02 04 06 08 1 12 14

[au

]micromicro

dNd

M

0

5

10

15

20

25

3minus10times

from OS mixing

(PYTHIA)bfrom b

(PYTHIA)cfrom c

(a) Reference

]2c [GeVmicromicroM0 02 04 06 08 1 12 14

[au

]micromicro

dNd

M

0

5

10

15

20

25

3minus10times

microfrom OS MC uncorr

(FONLL)cfrom c

(FONLL)bfrom b

(b) Alternative

Figure 61 Normalized shape of continuum templates

The shape of the correlated continuum is determined by the fit by optimizing therelative weight of three invariant mass templates as explained in section 522 To eval-uate the systematic uncertainty associated to the choice of this set of templates analternative set of templates have been considered The alternative templates correspond

82 Chapter 6 Systematics Evaluation

to the reconstructed open charmbeauty dimuons generated with the lower limit of theFONLL prediction range (offering the largest deviation from the corresponding referencetemplates see figure 412) and to the OS dimuons from the MC simulations of uncor-related muons already considered for the validation of the event mixing technique (seesection 512) Considering the alternative set of templates has an average impact of minus1for the ηrarr micro+microminusγ 2 for the ωrarr micro+microminus and 9 for the φrarr micro+microminus signals

616 Systematic Uncertainty ComputationAs already mentioned the systematic uncertainty on the signal extraction is computedseparately for the η rarr micro+microminusγ ω rarr micro+microminus and φ rarr micro+microminus processes as the standarddeviation of the distribution of value obtained from the systematic tests described above

σ2 = 1N

testssumi

(xi minus 〈x〉)2 (61)

where xi is the outcome of the i-th systematic test out of the N available tests andthe expectation value 〈x〉 is taken as the outcome of the reference fit This approach isjustified by the assumption that for each source of systematics the associated uncertaintycan be assumed to be Gaussian This evaluation is done for each pT-y interval consideredin this analysis

The global uncertainty on the signal extraction is reported in table 62 for the threesignals extracted with the fit procedure since its value depends on the pT and y intervalthe minimum and maximum values are quoted The average uncertainties correspondingto the considered systematic tests on the signal extraction are also reported in the table

Syst test ηrarr micro+microminusγ ωrarr micro+microminus φrarr micro+microminus

BR ηrarr micro+microminus lt 1 2 2 BR ωrarr micro+microminusπ0 3 3 2 Ratio σηprimeσφ lt 1 3 2 Ratio σρσω 1 2 2 Upper fit limit 5 6 8 Templates for the correlatedcontinuum 6 4 5

Standard deviation from (61) 1 - 22 2 - 12 1 - 16

Table 62 Summary of the systematic tests considered on the signal extraction procedure

62 Systematics from the MC inputThe first source of systematic uncertainty considered for the (Atimes ε) evaluation is thechoice of the input kinematic distributions assumed in MC simulations for the generatedη ρ ω ηprime and φ mesons see section 411 The reference choice being the correlated

63 Systematics on Trigger Efficiency 83

pT-y input from PHOJET the alternative MC input has been based on parametrized non-correlated pT and y distributions form PYTHIA6 The corresponding systematic uncer-tainty has been evaluated for each pT and y interval considered in this analysis by takingthe difference of the (Atimes ε) value estimated with the reference and the alternative MCinputs The corresponding average impact on the extraction of the signals of interest is5 55 and 1 respectively for the ηrarr micro+microminusγ ωrarr micro+microminus and φrarr micro+microminus signals

63 Systematics on Trigger Efficiency

The systematics on the trigger efficiency has been determined by comparing the proba-bility of reconstructing dimuons of a given kinematics with two different trigger responsefunctions one obtained from the data and the other from MC simulations The standardprocedure to estimate the systematic uncertainty from the trigger response function canbe summarized as follows

bull Fit the ratio low-pTA-pT obtained dividing the pT distribution of single muonsmatching the low-pT trigger condition by the pT distribution of single muons match-ing the A-pT condition (see paragraph e on section 223) This ratio is evaluatedboth in data and in realistic MC simulations and the corresponding fits define thetrigger response function

bull Select muons matching the A-pT trigger condition in the MC simulation of a specificdimuon signal and weigh each of them (according to their pT) by either the dataor the MC trigger response function

bull Extract the number of reconstructed dimuons under the two assumptions of thetrigger response function The difference is the systematics uncertainty of the triggerefficiency

631 Evaluation of the Trigger Response Function

The definition of the trigger response function given above cannot be used in the presentanalysis because in the considered data set the low-pT and the A-pT trigger matchingconditions coincide Therefore an alternative definition of the trigger response function isadopted here namely the ratio low-pTAll where the denominator is the pT distributionof All reconstructed muons imposing no trigger matching condition

Unfortunately this new definition of the trigger response function cannot be safelyapplied to the data because the All muon sample is contaminated by a non-negligiblehadronic component In this case one can still estimate the low-pTAll for the datastarting from the ratio of the corresponding MC ratio through a dataMC conversionfactor This conversion factor is defined as the ratio between the trigger response functionslow-pTA-pT of data and MC estimated in a dataset (B) as close as possible to the one(A) considered in the present analysis and characterized by different thresholds for the

84 Chapter 6 Systematics Evaluation

low-pT and A-pT trigger matching conditions

low-pT

All

∣∣∣∣∣data

A

(pT) = low-pT

All

∣∣∣∣∣MC

A

(pT)timeslow-pTA-pT

∣∣∣dataB

(stimes pT)low-pTA-pT

∣∣∣MC

B(stimes pT)

(62)

with the pT dependence of the trigger response functions in the reference dataset B beingldquostretchedrdquo by the s factor

s = pcutT (MC B)pcutT (MC A) (63)

where pTcut(MC x) is defined as the pT value for which the trigger response function

(low-pTAll or low-pTA-pT respectively for the datasets A and B) reaches half the dif-ference between the maximum and minimum This approach is correct as long as twoassumptions are valid

bull the trigger response per local board does not change with time

bull the relative difference dataMC between the low-pTA-pT trigger response func-tions from data and MC does not change when considering the low-pTAll triggerresponse functions

The low-pTA-pT trigger response functions defining the dataMC conversion factorin equation (62) can be replaced by a parametrization given by the function

F (pT pcutT σ) = 1 + p0 times

erfpT minus pcut

Tsradic

2σs

minus 1 (64)

based on the three free parameters p0 pcutT and σIn the present analysis the reference dataset B has been assumed to be the 2015 Pb-Pb

dataset (restricted to the peripheral collisions in the 60-100 centrality class) taken atradics = 502 TeV this choice is also used in other dimuon analyses based on the pp dataset

atradics = 5 TeV and the p-Pb dataset at radicsNN = 5 mdash 816 TeV

632 ResultsThe two versions of the trigger re-weighting described above produced two alternativeestimations of the (Atimes ε) for the three considered processes For each pT-y cell consideredin the analysis we retained the alternative version giving the largest deviation with respectto the reference value this deviation is shown in the form of a ratio in figure 62 Theabsolute deviation of this ratio is taken as the systematic uncertainty on the triggerefficiency the average values of this uncertainty are 2 06 and 1 respectively forthe ηrarr micro+microminusγ ωrarr micro+microminus and φrarr micro+microminus processes In the analysis this uncertaintyhas been evaluated for each specific pT-y cell considered for the extraction of the signalSystematic uncertainty values as large as 30 were tolerated in this analysis this resultedin the exclusion of the (minus350 lt y lt 325 04 lt pT lt 06 GeVc) interval for theηrarr micro+microminusγ signal affected by a systematic on the trigger efficiency larger than 70

64 Systematics on Tracking Efficiency 85

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

06

07

08

09

1

11

12

13

14 RefTrigg-reweight

γmicromicrorarrη ]εtimes[ A

(a) ηrarr micro+microminusγ

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

06

07

08

09

1

11

12

13

14 RefTrigg-reweightmicromicrorarrω ]εtimes[ A

(b) ωrarr micro+microminus

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

06

07

08

09

1

11

12

13

14 RefTrigg-reweight

micromicrorarrφ ]εtimes[ A

(c) φrarr micro+microminus

Figure 62 Ratio of Atimes ε for original simulation over the re-weighted simulation for estimating thesystematics associated to the trigger efficiency

64 Systematics on Tracking Efficiency

The systematics on tracking efficiency is one of the contributions to the uncertainty on the(Atimes ε) estimation To compute this uncertainty one has to evaluate the ratio betweenthe tracking efficiencies of data and MC

641 Preliminary Check

Before studying the tracking efficiencies in data and MC it must be verified that thestatus of the detector described in the realistic MC simulations is compatible with thestatus of the detector reflected by the data This is done by inspecting the cluster mapsof the tracking chambers in data and MC in this way one can verify whether the deadareas in the data are correctly reproduced in the MC and no additional dead area isintroduced An example of such comparison is shown in figure 63

Another point to be checked is the variation of the high voltage supplied to the track-ing chambers with respect to the value 16 kV corresponding to the nominal operatingconditions During Run 2 indeed some frequent high voltage drops to 14 kV were spot-ted resulting in a degraded efficiency of the chambers Since this intermediate behaviorbetween the full operation and the off status cannot be easily reproduced in MC specificdetector elements being significantly affected by high voltage drops are added to a ldquorejectlistrdquo and excluded from the reconstruction both in data and MC Alternatively when thispathological high voltage behavior only affects a limited fraction of the considered datasample full runs can be excluded it was the case in the present analysis where 4 runsof the LHC16n period were rejected to avoid major discrepancies between data and MC

After checking the agreement between data and MC concerning the detector statusand the behavior of the high voltage it is possible to launch the evaluation of the trackingefficiency both in data and MC

86 Chapter 6 Systematics Evaluation

Figure 63 Comparison between cluster maps of tracking chamber 4 in data (left) and MC (right)

642 Tracking Efficiency EvaluationThe tracking efficiency (εglobal) is computed as the product of the efficiency (εSti) of eachtracking station

εglobal = εSt1 middot εSt2 middot εSt3 middot εSt45 (65)

The fact the efficiencies of stations 4 and 5 are combined together in the efficiency εSt45 isdue to the logic operating mode implemented in the tracking algorithm [7894] requiringone cluster per station for stations 1 2 and 3 and three clusters from the combinedstations 4-5

Ch1 Ch2 Ch3 Ch4 Ch5 Ch6 Ch7 Ch8 Ch9 Ch10

NSt21-1

St1 St2 St3 St4 St5

NSt20-1

NSt21-0

NSt20-0

St45

Figure 64 Sketch showing the arrangement of the chambers into stations and the possible responsesof one station to the passage of a particle

64 Systematics on Tracking Efficiency 87

To evaluate the efficiency of a given station one has to start considering the efficiencyof the chamber composing the station (see section 223 for a more detailed description ofthe muon spectrometer structure) To evaluate the efficiency of each tracking chamberthe assumption is done that its efficiency does not depend on the efficiency of the otherchambers under this assumption the redundancy of the information given by the twochambers of a specific station can be used to determine the efficiency of each chamberseparately Figure 64 shows the possible responses of station 2 to the passage of aparticle Generalizing to the case of an arbitrary station k the reconstructed track canhave a cluster in both chambers (NStk

1-1 ) a cluster either in the first or the second of thetwo stations (NStk

1-0 or NStk0-1 ) or the track does not fulfill the tracking conditions so it is not

reconstructed (NStk0-0 ) Still focusing on station k composed of chamber i and j(= i+ 1)

one can express the number of reconstructed tracks (Ntot each of them crossing stationk due to the conditions imposed by the tracking algorithm) as

Ntot = NStk1-1 +NStk

0-1 +NStk1-0 (66)

Under the assumption that the efficiencies of chambers i and j are independent NStk1-1

NStk1-0 and NStk

0-1 can be expressed as a function of Ntot

NStk1-1 = Ntot middot εChi middot εChj (67)

NStk1-0 = Ntot middot εChi middot (1minus εChj) (68)

NStk0-1 = Ntot middot (1minus εChi) middot εChj (69)

By combining the above equations the efficiencies of chamber i and j are given by

εChi = NStk1-1

NStk1-1 +NStk

0-1εChj = NStk

1-1NStk

1-1 +NStk1-0

(610)

The individual chamber efficiencies can be combined to compute the efficiency of eachstation In the case of the first three stations the efficiency is defined as the probabilityfor a muon to be detected by at least one of the two chambers

εSt1(23) = 1minus(1minus εCh1(35)

) (1minus εCh2(46)

)= εCh1(35) εCh2(46) +

(1minus εCh1(35)

)εCh2(46) + εCh1(35)

(1minus εCh2(46)

) (611)

For the last two stations the efficiency has to be calculated as a whole due to the trackingalgorithm requirements This efficiency is the probability that a muon is detected by atleast three out of the four chambers in the stations the corresponding formula is thegeneralization of equation (611)

εSt45 =10prodi=7

εChi +10sumi=7

(1minus εChi)10prodj=7j 6=i

εChj

(612)

88 Chapter 6 Systematics Evaluation

643 MC parametrization

In order the tracking efficiency estimation in the MC to be reliable the considered para-metric muon generator must be tuned in order to reproduce the reconstructed kinematicsof the single muons measured in pp collisions at

radics = 13 TeV considered in the present

analysis The tuning is performed by means of a recursive procedure illustrated in fig-ure 65 which includes the following steps

1 Run MC simulations of single muons with given input pT and y distributions

2 Compute the (Atimes ε) as a function of pT and y

3 Use the (Atimes ε) to correct the reconstructed muon distributions from data

4 Compute the ratio as a function of both pT and y between the corrected datadistribution and the kinematic distributions considered for the MC input Shouldthis ratio be compatible with one convergence is reached and the procedure isstopped

5 Inject the corrected pT and y data distributions as the new input for MC simulation

until step 4 is equal to one

First Set of MC simulation

MC gen distribMC rec distrib

MC (Atimes ε)Rec

data distrib

Data corr distrib

Datacoor distrib =MC gen distrib

Data corr distrib rarr MC gen distrib

Done

1

2

3 34

No

Yes

51

Figure 65 Illustration of the data driven method used to tune the input distribution of single muon

65 Summary of Systematic Uncertainty 89

644 ResultsTracking efficiency estimations from the data and from the tuned MC simulation areshown in figure 66 as a function of pT y the azimuthal angle ϕ and the run number A2 systematic uncertainty is observed in average for single muon from the comparisonbetween data and MC For the dimuon signals the systematic uncertainty on the trackingefficiency is estimated to be twice the systematics on the single muons in this case thisresults in a 4 systematic uncertainty independent of pT and y

run number

2536

59

2541

28

2543

78

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

effic

ienc

y

0

02

04

06

08

1

Simulation Data

run number2536

59

2541

28

2543

78

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

EffD

ata

EffS

im

09

1

11

B TeyssierWork Thesis

Figure 66 Tracking efficiency measured in data and in the tuned MC simulation as a function ofrun number

65 Summary of Systematic UncertaintyIn table 63 are summarized the various sources of systematic uncertainties discussed inthis chapter For each of these sources and each signal of interest for this analysis wereport the value of the systematic uncertainty when the uncertainty values depend onthe pT or the y interval their maximum and minimum values are quoted

Syst source η ω φ

Signal extraction 1 - 22 2 - 12 1 - 157 MC input 5 55 1 Trigger efficiency 1 - 31 1 - 24 1 - 25 Branching ratio 13 2 1 Tracking efficiency 4 Luminosity 5

Table 63 Summary of the systematic uncertainty sources contributing to the measurement of theη ρω and φ meson cross-section

Chapter 7

Light Neutral Meson Production

Summary71 Estimation of the Number of Generated Mesons 91

711 The Two-Body Decay Case 91712 The Dalitz Decay Case 92

72 Cross-Section Production for Light Neutral Mesons 93

721 Double-Differential η Meson Production 93722 ρω Meson Production 94723 Double-Differential φ Meson Production 98

This chapter describes the steps followed to convert the reconstructed signal into cross-section for the η ρω and φ mesons The pT dependence of the production cross-sectionis extracted in six y intervals and compared to the predictions of the available modelsIn the case of the φ and ρω mesons the pT dependence of the rapidity-integratedcross-section is also derived allowing for the comparison with the results from existingmeasurements in pp collisions in the same rapidity range

71 Estimation of the Number of Generated MesonsThe very first step after signal extraction consists in correcting the number of recon-structed dimuons for the Atimesε evaluated with the MC simulations discussed in section 41In the case of the two-body decays ρω rarr micro+microminus and φ rarr micro+microminus the information onthe dimuons can be directly converted into the corresponding information on the parentmesons by correcting for the branching ratios of the involved decays In the case of theDalitz decay ηrarr micro+microminusγ an additional step is required to convert the dimuon kinematicsto the η meson one before correcting for the branching ratio

711 The Two-Body Decay CaseAs far as the two-body decays of the ρω and φ mesons are concerned the corrected num-ber of mesons (Nρω and Nφ respectively) corresponding to the reconstructed dimuonsN recmicromicro is given for each pT-y interval considered in this analysis by the following formula

Nρω φ(pT y) =N recmicromicro (pT y)

[Atimes ε]micromicro (pT y) middotBRmiddot ∆pT middot ∆y (71)

92 Chapter 7 Light Neutral Meson Production

where [Atimes ε]micromicro (pT y) is the product of the acceptance and the dimuon reconstructionefficiency evaluated in the specific pT-y cell BR is the branching ratio of the considereddecay channel (see table 43) and ∆pT middot ∆y are the widths of the pT-y cell For theestimation relative to the ρω mesons N rec

micromicro (pT y) [Atimes ε]micromicro (pT y) and the BR arereferred to the ωrarr micro+microminus decay

712 The Dalitz Decay Case

When dealing with the Dalitz decay of the η we start by correcting the number ofreconstructed dimuons for the Atimes ε and the widths of the considered pT-y cell

Ngenmicromicro (pT y) =

N recmicromicro (pT y)

[Atimes ε]micromicro (pT y) middot ∆pT middot ∆y (72)

Contrary to the two-body case the corrected kinematics distribution of the dimuon doesnot coincide with the one of the parent meson due to the Dalitz decay kinematics implyinga third body

)ηyηT

pId(0 50 100 150 200 250 300

)micromicroymicromicro T

pId

(

0

50

100

150

200

250

300

1

10

210

310

410

510

610

710

810

)micromicroy micromicroT

p ηy ηT

pT(

Figure 71 Correlation matrix T(pηT yη pmicromicroT ymicromicro) represented in cell coordinates

72 Cross-Section Production for Light Neutral Mesons 93

So to obtain the correct kinematic distributions of the parent η meson an additionaltransformation is needed

Nηrarrmicromicroγ(pT y) = Tminus1 middot Ngenmicromicro (pT y) (73)

where Tminus1 is the inverse of the matrix encoding the correlation between the kinematics ofthe parent η meson and the one of the dimuon both expressed in terms of pT and y TheT(pηT yηp

micromicroT y

micromicro) is shown in figure 71 each T(pηT yη pmicromicroT y

micromicro) element of the matrix isdefined as the probability of an η meson with a given (pηT yη) kinematics to produce adimuon with a given (pmicromicroT ymicromicro) kinematics so that one can write

Ngenmicromicro (pT y) = Tmiddot Nηrarrmicromicroγ(pT y) (74)

from which equation (73) is derived The row-column indexes of the elements of theTmatrix identify a specific pηT yη and pmicromicroT ymicromicro cell respectively In this specific analysisthe phase space limits considered for both the η and the dimuon are 20 lt y lt 45 and00 lt pT lt 150 GeVc in this way any possible edge effect affecting the numericalproblem will have a limited impact on the phase space covered by the available data

Once the correction expressed by equation (73) is performed the resulting kinematicdistribution is further scaled for the η rarr micro+microminusγ branching ratio in order to obtain thecorrect normalization for the Nη(pT y) distribution

72 Cross-Section Production for Light NeutralMesons

The Nηρωφ(pT y) distributions obtained after correcting for the Atimesε and the branchingratio (and for the meson-dimuon kinematic correlation in the case of the η) must be furthernormalized to the integrated luminosity Lint corresponding to the analyzed data sample(the evaluation of the integrated luminosity is discussed in section 32) This normalizationallows one to obtain the cross-section for the three mesons

d2σ(pT y)dpTdy = Nηρωφ(pT y)times 1

Lint (75)

721 Double-Differential η Meson Production

In figure 72 the pT distributions of the dimuon coming from the η rarr micro+microminusγ decay areshown for the six y interval considered in this analysis These distributions representthe Ngen

micromicro (pT y) input from which the kinematic distribution of the parent meson can beextracted via equation (73) The implementation in the current analysis of the kinematiccorrection based on equation (73) is however still under way for this reason no resulton the η meson cross-section is shown in the rest of the chapter

94 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

ydT

pd η

dN

510

710

910

1110

13100250 lt y lt 275 x 101275 lt y lt 300 x 102300 lt y lt 325 x 103325 lt y lt 350 x 104350 lt y lt 375 x 105375 lt y lt 400 x 10

B TeyssierWork Thesis

Figure 72 Comparison of the pT distribution of η dimuon generated as a function of y

722 ρω Meson ProductionFor the ρω mesons the double-differential pT-y production cross-section has been eval-uated in the available phase space the results are shown in figure 73 as a function ofpT in six y intervals For each y interval the measured cross-section has been comparedto the predictions of PYTHIA8-Monash2013 [95] and PHOJET The comparison is shown inthe panels of figure 74 the two models systematically overestimate by a factor sim 2 thedata in the full accessible pT range for each of the considered y intervals

In figure 75 the y dependence of the production cross-section is shown integratedover the pT range 20 lt pT lt 65 GeVc common to the considered y intervals Thecomparison with the predictions from PYTHIA8-Monash2013 and PHOJET confirms thatthe models overestimate the data by a factor sim 2 Besides the global overestimation thePHOJET prediction seems to provide a better description than PYTHIA8-Monash2013 of they dependence of the data

The ρω production cross-section was also measured in ALICE in pp collisions atradics =

7 TeV integrated over 25 lt y lt 40 as a function of pT in the 10 lt pT lt 50 GeVcrange In order to compare our data to the ones at

radics = 7 TeV the production cross-

section measured in this analysis has been integrated over the full accessible 25 lt y lt 40range As it can be seen from figure 73 the integration over 25 lt y lt 40 was possiblelimited to the 20 lt pT lt 65 GeVc range The comparison between the two energiesshows that the 13 TeV cross-section is larger than the 7 TeV one by a factor sim 2 seefigure 76

72 Cross-Section Production for Light Neutral Mesons 95

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

210

310

410

510

610

0250 lt y lt 275 x 10

1275 lt y lt 300 x 10

2300 lt y lt 325 x 10

3325 lt y lt 350 x 10

4350 lt y lt 375 x 10

5375 lt y lt 400 x 10

B TeyssierWork Thesis

Figure 73 Comparison of the pT distribution of ω meson as a function of y

96 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

375 lt y lt 400

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

3minus10

2minus10

1minus10

1

10350 lt y lt 375

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

325 lt y lt 350

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

300 lt y lt 325

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

275 lt y lt 300

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

250 lt y lt 275

Pythia8

PHOJETB Teyssier

Work Thesis

Figure 74 pT distributions of ω meson for various y intervals

72 Cross-Section Production for Light Neutral Mesons 97

y4minus 2minus 0 2 4

[mb]

yωσd

0

05

1

15

2

25

3

(reflected)ω

(measured)ω

Pythia8 - monash2013

Phojet

c lt 65 GeVT

p20 lt

B TeyssierWork Thesis

Figure 75 y distribution of ω meson integrated in 20 lt pT lt 65 GeVc

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσ2 d

3minus10

2minus10

1minus10

1

=7TeVspp at

=13TeVspp at

B TeyssierWork Thesis

Figure 76 pT distribution of ω meson integrated in y and comparison with measurements at7 TeV [43]

98 Chapter 7 Light Neutral Meson Production

723 Double-Differential φ Meson ProductionAs for the ρω mesons the double-differential pT-y production cross-section has beenevaluated for the φ meson too in the available phase space the results are shown infigure 77 as a function of pT in the y intervals considered in the analysis extended at mid-rapidity with the φ rarr K+Kminus measurements [96] The comparison of the data with thepredictions of the PYTHIA8-Monash2013 and PHOJET models is shown for each y intervalconsidered in the analysis in the panels of figure 78 contrary to what observed for theω meson the PYTHIA8-Monash2013 prediction provides a good description of the dataThe PHOJET prediction on the contrary still slightly fails in estimating the normalizationand the shape of the pT dependence of the production cross-section

The y dependence of the production cross-section is shown in figure 79 integratedover the pT range 20 lt pT lt 65 GeVc common to the considered y intervals As one cansee the data points sit between the predictions from PYTHIA8-Monash2013 and PHOJETwhich both slightly fail in describing the shape of the y dependence The results for theφ meson production in the dikaon channel provide an additional point at mid-rapiditywhich could be compared to the forward measurements presented here

Results for the φ meson production cross-section are also available from ALICE mea-surements in pp collisions at

radics = 276 502 7 and 8 TeV integrated over 25 lt y lt 40

as a function of pT in various pT ranges In order to compare our data to the ones atlower energies the φ meson production cross-section measured in this analysis has beenintegrated over the full accessible 25 lt y lt 40 range As it can be seen from figure 77this integration was possible limited to the 20 lt pT lt 65 GeVc range As expected thecross-section at 13 TeV is found to be larger than the measurements at lower energies

The energy dependence of the φ meson production cross-section has been studiedintegrating the present measurement over the y and pT ranges 25 lt y lt 40 and15 lt pT lt 50 GeVc common to the data at the various available energies Theresults are shown in figure 711 compared with the PYTHIA8-Monash2013 and PHOJETprediction the trend as a function of

radics is found to be approximately linear in the con-

sidered energy range with the PHOJET model in good agreement with the data and thePYTHIA8-Monash2013 prediction systematically underestimating the results The analysisstrategy at 13 TeV is being slightly revised in order to reduce the systematic uncertaintyassociated to the integrated cross-section by optimizing the integration procedure namelyintegrating over the rapidity before signal extraction

72 Cross-Section Production for Light Neutral Mesons 99

]c [GeVT

p0 2 4 6 8 10 12

)]c [m

b(G

eV

ydT

pd φσd

4minus10

3minus10

2minus10

1minus10

1

10

210

310

410

510

-1|lt05 x 10y |-

K+ Krarrφ0250 lt y lt 275 x 10

1275 lt y lt 300 x 10

2300 lt y lt 325 x 103325 lt y lt 350 x 10

4350 lt y lt 375 x 10

5375 lt y lt 400 x 10

B TeyssierWork Thesis

Figure 77 Comparison of the pT distribution of φ meson as a function of y extended at mid-rapidityby the φrarr K+Kminus measurements [96]

100 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1375 lt y lt 400

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

350 lt y lt 375

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1325 lt y lt 350

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

300 lt y lt 325

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

275 lt y lt 300

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

250 lt y lt 275

Pythia8

PHOJETB Teyssier

Work Thesis

Figure 78 pT distribution of φ meson for various y intervals

72 Cross-Section Production for Light Neutral Mesons 101

y4minus 2minus 0 2 4

[mb]

y φσd

0

01

02

03

04

05

(refkected)φ (dikaon measurement)φ (measured)φ

Pythia8 - monash2013

Phojet

c lt 65 GeVT

p20 lt

B TeyssierWork Thesis

Figure 79 y distribution of φ meson integrated in 20 lt pT lt 65 GeVc extended at mid-rapidityby the φrarr K+Kminus measurements [96]

102 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσ2 d

3minus10

2minus10

1minus10

1 =276TeVspp at

=5TeVspp at

=7TeVspp at

=8TeVspp at

=13TeVspp at

lt 40y25 lt

B TeyssierWork Thesis

Figure 710 φ meson pT distribution integrated over 25 lt y lt 40 in pp collisions atradics = 13 TeV

(this analysis) compared to previous measurements at lower energies

72 Cross-Section Production for Light Neutral Mesons 103

B TeyssierWork Thesis

Figure 711 Energy dependence of the φ meson production cross-section in 25 lt y lt 40 and15 lt pT lt 50 GeVc

Conclusions and Perspectives

This work focused on the study of the production cross-section of the η ρω and φmesons This study has been achieved by performing a double-differential pT-y analysisin the phase space available for each meson Results have been compared to the availabletheoretical predictions from the PYTHIA8 and PHOJET models this comparison resultedin a better datamodel agreement for the φ meson than for the ρω meson Moreoverexisting results at several lower collision energies in the same y interval allowed toinvestigate the energy evolution of the production cross-section for the φ meson andlimited to the comparison with the

radics = 7 TeV results for the ρω mesons For the φ

meson the energy evolution of the production cross-section integrated over 25 lt y lt 40and 15 lt pT lt 50 GeVc was found to be approximately linear with the PHOJET modelin good agreement with the data and the PYTHIA8-Monash2013 prediction systematicallyunderestimating the results In a next future the results for the φ meson from thepresent analysis could also be compared to the mid-rapidity measurement performed inALICE in the dikaon channel

The present analysis did not exploit the full potential of the large data sample availablein pp collisions at

radics = 13 TeV which could possibly profit from the combination of the

2016 and 2017 data taking Among the measurements which could still be performedbased on the analysis of the low-mass dimuon region one can cite

bull the study of the multiplicity dependence of the light-neutral meson production

bull the search for strangeness enhancement collective phenomena and azimuthalanisotropies in light-neutral meson production in high-multiplicity pp events

bull the study of the light-neutral meson polarization

Finally beyond the standard dimuon analyses the large pp data sample atradics = 13 TeV

could also be exploited for the search of the first evidence of the η rarr 2micro+2microminus decayfor which only an upper limit is currently available from literature [4] The proximity ofthe η meson mass to the 4mmicro threshold makes the observation of this decay particularlychallenging and sensitive to the description to the combinatorial background

Appendix A

List of Runs

000253659 000253680 000253682 000253748 000253751 000253755 000253756 000253757000253813 000253819 000253825 000253826 000253832 000253834 000253951 000253956000253957 000253958 000253961 000253978

Table A1 Run list for period LHC16f

000254128 000254147 000254148 000254149 000254174 000254175 000254178 000254193000254199 000254204 000254205 000254293 000254302 000254304 000254331 000254332

Table A2 Run list for period LHC16g

000254378 000254381 000254394 000254395 000254396 000254419 000254422 000254476000254479 000254604 000254606 000254608 000254621 000254629 000254630 000254632000254640 000254644 000254646 000254648 000254649 000254651 000254652 000254653000254654 000254983 000254984 000255008 000255009 000255010 000255042 000255068000255071 000255073 000255074 000255075 000255076 000255079 000255082 000255085000255086 000255091 000255111 000255154 000255159 000255162 000255167 000255171000255173 000255176 000255177 000255180 000255182 000255240 000255242 000255247000255248 000255249 000255251 000255252 000255253 000255255 000255256 000255275000255276 000255280 000255283 000255350 000255351 000255352 000255398 000255402000255415 000255440 000255442 000255447 000255463 000255465 000255466 000255467000255469

Table A3 Run list for period LHC16h

000255515 000255533 000255534 000255535 000255537 000255538 000255539 000255540000255542 000255543 000255577 000255583 000255591 000255592 000255614 000255615000255616 000255617 000255618

Table A4 Run list for period LHC16i

108 Appendix A List of Runs

000256146 000256147 000256148 000256149 000256156 000256157 000256158 000256161000256169 000256204 000256207 000256210 000256212 000256213 000256215 000256219000256222 000256223 000256227 000256228 000256231 000256281 000256282 000256283000256284 000256287 000256289 000256290 000256292 000256295 000256297 000256298000256302 000256307 000256311 000256356 000256357 000256361 000256362 000256363000256364 000256365 000256366 000256368 000256372 000256373 000256415 000256417000256418 000256420

Table A5 Run list for period LHC16j

000256504 000256506 000256510 000256512 000256552 000256554 000256556 000256557000256560 000256561 000256564 000256565 000256567 000256589 000256591 000256592000256619 000256620 000256658 000256676 000256677 000256681 000256684 000256691000256694 000256695 000256697 000256941 000256942 000256944 000257011 000257012000257021 000257026 000257028 000257071 000257077 000257080 000257082 000257083000257084 000257086 000257092 000257095 000257224 000257260 000257318 000257320000257322 000257330 000257358 000257364 000257433 000257457 000257468 000257474000257487 000257488 000257490 000257491 000257492 000257530 000257531 000257540000257541 000257560 000257561 000257562 000257563 000257564 000257565 000257566000257587 000257588 000257590 000257592 000257594 000257595 000257601 000257604000257605 000257606 000257630 000257632 000257635 000257636 000257642 000257644000257682 000257684 000257685 000257687 000257688 000257694 000257697 000257724000257725 000257727 000257733 000257734 000257735 000257737 000257892 000257893000257901 000257912 000257932 000257936 000257937 000257939 000257957 000257958000257960 000257963 000257979 000257986 000257989 000258008 000258012 000258014000258017 000258019 000258039 000258041 000258042 000258045 000258048 000258049000258059 000258060 000258062 000258063 000258107 000258108 000258109 000258113000258114 000258117 000258178 000258197 000258202 000258203 000258204 000258256000258257 000258258 000258270 000258271 000258273 000258274 000258278 000258280000258299 000258301 000258302 000258303 000258306 000258307 000258332 000258336000258359 000258387 000258388 000258391 000258393 000258399 000258426 000258452000258454 000258456 000258477 000258498 000258499 000258537

Table A6 Run list for period LHC16k

000258919 000258920 000258921 000258923 000258931 000258962 000258964 000259086000259099 000259117 000259118 000259162 000259164 000259204 000259261 000259263000259264 000259269 000259270 000259271 000259272 000259273 000259274 000259302000259303 000259305 000259307 000259334 000259339 000259340 000259341 000259342000259378 000259379 000259381 000259382 000259394 000259395 000259396 000259469000259471 000259477 000259649 000259650 000259668 000259697 000259700 000259703000259704 000259705 000259711 000259713 000259750 000259751 000259756 000259788000259789 000259822 000259841 000259842 000259860 000259866 000259867 000259868000259888 000259954 000259961 000259979 000260010 000260011 000260014

Table A7 Run list for period LHC16l

109

000260218 000260240 000260310 000260312 000260313 000260338 000260340 000260351000260354 000260357 000260379 000260411 000260432 000260435 000260437 000260440000260441 000260447 000260471 000260472 000260475 000260476 000260481 000260482000260487 000260490 000260495 000260496 000260497 000260537 000260539 000260540000260541 000260542 000260564 000260586 000260611 000260613 000260614 000260615000260616 000260647

Table A8 Run list for period LHC16m

000260649 000260650 000260657 000260667 000260671 000260672 000260689 000260691000260693 000260695 000260700 000260704 000260710 000260713 000260722 000260723000260727 000260728 000260740 000260741 000260749 000260750 000260751 000260752000260763 000260770 000260777 000260782 000260784 000260786 000260788 000260804000260808 000260809 000260810 000260815 000260913 000260914 000260920 000260934000260935 000260936 000260938 000260960 000260963 000260992 000260993 000261020000261022 000261025 000261026 000261027 000261052 000261055 000261065 000261076000261083 000261088 000261093 000261094 000261095 000261099 000261100

Table A9 Run list for period LHC16n

000262399 000262418 000262419 000262422 000262423 000262424 000262428 000262430000262451 000262487 000262492 000262528 000262532 000262533 000262537 000262563000262567 000262568 000262569 000262570 000262571 000262572 000262574 000262578000262583 000262593 000262594 000262628 000262632 000262635 000262705 000262706000262713 000262717 000262719 000262723 000262725 000262727 000262760 000262768000262776 000262777 000262778 000262841 000262842 000262844 000262847 000262849000262853 000262855 000262858 000263332 000263487 000263490 000263496 000263497000263647 000263652 000263653 000263654 000263657 000263662 000263663 000263682000263689 000263690 000263691 000263737 000263738 000263739 000263741 000263743000263744 000263784 000263785 000263786 000263787 000263790 000263792 000263793000263803 000263810 000263813 000263823 000263824 000263829 000263830 000263861000263863 000263866 000263905 000263916 000263917 000263920 000263923 000263977000263978 000263979 000263981 000263984 000263985 000264033 000264035

Table A10 Run list for period LHC16o

000264076 000264078 000264082 000264085 000264086 000264109 000264110 000264129000264137 000264138 000264139 000264164 000264168 000264188 000264190 000264194000264197 000264198 000264232 000264233 000264235 000264238 000264259 000264260000264261 000264262 000264264 000264265 000264266 000264267 000264273 000264277000264279 000264281 000264305 000264306 000264312 000264336 000264341 000264345000264346 000264347

Table A11 Run list for period LHC16p

Appendix B

Raw-Background Comparison mdashfigures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150

lt 275y250 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 300y275 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 325y300 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

25310times

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B1 Evolution of signal and combinatorial background shapes for 000 lt pT lt 020 GeVc

112 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

lt 275y250 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 300y275 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 325y300 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 375y350 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 400y375 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B2 Evolution of signal and combinatorial background shapes for 020 lt pT lt 040 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 275y250 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5

310times

lt 300y275 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20310times

lt 325y300 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 400y375 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B3 Evolution of signal and combinatorial background shapes for 040 lt pT lt 060 GeVc

113

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 275y250 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 300y275 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 325y300 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

80310times

lt 375y350 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 400y375 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B4 Evolution of signal and combinatorial background shapes for 060 lt pT lt 080 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 275y250 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8310times

lt 300y275 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 325y300 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 350y325 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

80310times

lt 375y350 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

50

310times

lt 400y375 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B5 Evolution of signal and combinatorial background shapes for 080 lt pT lt 100 GeVc

114 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600 lt 275y250 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 300y275 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 325y300 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 350y325 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60310times

lt 375y350 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 400y375 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B6 Evolution of signal and combinatorial background shapes for 100 lt pT lt 120 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 275y250 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 300y275 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

50310times

lt 325y300 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

310times

lt 350y325 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

310times

lt 375y350 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

50310times

lt 400y375 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B7 Evolution of signal and combinatorial background shapes for 120 lt pT lt 160 GeVc

115

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4310times

lt 275y250 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 300y275 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 325y300 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 375y350 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 400y375 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B8 Evolution of signal and combinatorial background shapes for 160 lt pT lt 200 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5310times

lt 275y250 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 300y275 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20310times

lt 350y325 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 375y350 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

310times

lt 400y375 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B9 Evolution of signal and combinatorial background shapes for 200 lt pT lt 240 GeVc

116 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 275y250 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

310times

lt 300y275 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12310times

lt 325y300 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

310times

lt 375y350 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5

310times

lt 400y375 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B10 Evolution of signal and combinatorial background shapes for 240 lt pT lt 280 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 275y250 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 300y275 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 325y300 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5

310times

lt 350y325 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 375y350 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3310times

lt 400y375 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B11 Evolution of signal and combinatorial background shapes for 280 lt pT lt 320 GeVc

117

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25310times

lt 275y250 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 300y275 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 325y300 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 350y325 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 375y350 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 400y375 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B12 Evolution of signal and combinatorial background shapes for 320 lt pT lt 360 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 275y250 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 300y275 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3310times

lt 325y300 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 350y325 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 375y350 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 400y375 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B13 Evolution of signal and combinatorial background shapes for 360 lt pT lt 400 GeVc

118 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 300y275 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 325y300 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 350y325 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 375y350 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800

lt 400y375 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B14 Evolution of signal and combinatorial background shapes for 400 lt pT lt 450 GeVc

119

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800 lt 275y250 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310times

lt 300y275 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 325y300 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310times

lt 350y325 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 375y350 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 400y375 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B15 Evolution of signal and combinatorial background shapes for 450 lt pT lt 500 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 275y250 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 300y275 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310times

lt 325y300 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 350y325 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 375y350 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300 lt 400y375 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B16 Evolution of signal and combinatorial background shapes for 500 lt pT lt 550 GeVc

120 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400 lt 275y250 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 300y275 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 325y300 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 350y325 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800

lt 375y350 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150

200

250

lt 400y375 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B17 Evolution of signal and combinatorial background shapes for 550 lt pT lt 600 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

lt 275y250 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 300y275 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12310times

lt 325y300 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1310times

lt 350y325 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 375y350 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150 lt 400y375 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B18 Evolution of signal and combinatorial background shapes for 600 lt pT lt 650 GeVc

121

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

lt 275y250 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800

lt 300y275 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800 lt 325y300 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600 lt 350y325 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 375y350 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

80

100

120

140

lt 400y375 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B19 Evolution of signal and combinatorial background shapes for 650 lt pT lt 700 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400 lt 275y250 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 300y275 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 325y300 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 375y350 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150 lt 400y375 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B20 Evolution of signal and combinatorial background shapes for 700 lt pT lt 800 GeVc

122 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 300y275 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 325y300 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800 lt 350y325 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 375y350 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150

200

lt 400y375 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B21 Evolution of signal and combinatorial background shapes for 800 lt pT lt 1000 GeVc

Appendix C

Hadronic-Cocktail fits mdash figures

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C1 Hadronic cocktail fits for 000 lt pT lt 020 GeVc

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 350y325 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 040 GeVT

p020 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 375y350 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 040 GeVT

p020 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 400y375 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 040 GeVT

p020 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C2 Hadronic cocktail fits for 020 lt pT lt 040 GeVc

124 Appendix C Hadronic-Cocktail fits mdash figures

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 350y325 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 400y375 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C3 Hadronic cocktail fits for 040 lt pT lt 060 GeVc

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

12

14

310times

lt 350y325 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 080 GeVT

p060 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 375y350 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 080 GeVT

p060 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

25

310times

lt 400y375 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 080 GeVT

p060 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C4 Hadronic cocktail fits for 060 lt pT lt 080 GeVc

125

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 325y300 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

25

310times

lt 350y325 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

50

310times

lt 375y350 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 400y375 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 375 lt y lt 400

Figure C5 Hadronic cocktail fits for 080 lt pT lt 100 GeVc

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

12

14

310times

lt 325y300 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 350y325 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 375y350 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 400y375 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 375 lt y lt 400

Figure C6 Hadronic cocktail fits for 100 lt pT lt 120 GeVc

126 Appendix C Hadronic-Cocktail fits mdash figures

Not available fit in250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

12

310times

lt 300y275 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 325y300 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

50

310times

lt 350y325 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

50

310times

lt 375y350 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 400y375 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 375 lt y lt 400

Figure C7 Hadronic cocktail fits for 120 lt pT lt 160 GeVc

Not available fit in250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 300y275 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 325y300 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 350y325 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30310times

lt 375y350 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

310times

lt 400y375 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 375 lt y lt 400

Figure C8 Hadronic cocktail fits for 160 lt pT lt 200 GeVc

127

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 275y250 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 300y275 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

310times

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 350y325 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 375y350 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 400y375 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C9 Hadronic cocktail fits for 200 lt pT lt 240 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 275y250 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 300y275 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

5

310times

lt 400y375 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C10 Hadronic cocktail fits for 240 lt pT lt 280 GeVc

128 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

310times

lt 275y250 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 300y275 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 325y300 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

5

310times

lt 350y325 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 375y350 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

310times

lt 400y375 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C11 Hadronic cocktail fits for 280 lt pT lt 320 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 275y250 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 300y275 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 325y300 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

310times

lt 350y325 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 375y350 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 400y375 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C12 Hadronic cocktail fits for 320 lt pT lt 360 GeVc

129

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 275y250 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 300y275 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 325y300 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp lt 325y300 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 350y325 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 375y350 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

310times

lt 400y375 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C13 Hadronic cocktail fits for 360 lt pT lt 400 GeVc

130 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 300y275 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp lt 300y275 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times lt 325y300 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times lt 350y325 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

12

310times

lt 375y350 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

800

lt 400y375 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C14 Hadronic cocktail fits for 400 lt pT lt 450 GeVc

131

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

800

lt 275y250 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

12

14310times lt 300y275 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

310times

lt 325y300 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1310times

lt 350y325 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 375y350 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

500

lt 400y375 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C15 Hadronic cocktail fits for 450 lt pT lt 500 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 275y250 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

800

lt 300y275 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 325y300 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 350y325 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 375y350 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 400y375 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C16 Hadronic cocktail fits for 500 lt pT lt 550 GeVc

132 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 275y250 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 300y275 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

500

lt 325y300 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 350y325 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 375y350 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 400y375 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C17 Hadronic cocktail fits for 550 lt pT lt 600 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300 lt 275y250 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 300y275 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 325y300 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 350y325 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 375y350 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 400y375 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C18 Hadronic cocktail fits for 600 lt pT lt 650 GeVc

133

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200 lt 275y250 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 300y275 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 325y300 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 350y325 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 375y350 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

20

40

60

80

100

lt 400y375 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C19 Hadronic cocktail fits for 650 lt pT lt 700 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 275y250 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 300y275 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 325y300 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 375y350 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 400y375 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C20 Hadronic cocktail fits for 700 lt pT lt 800 GeVc

134 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 300y275 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 325y300 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 350y325 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 375y350 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375Not available fit in

375 lt y lt 400

Figure C21 Hadronic cocktail fits for 800 lt pT lt 1000 GeVc

Bibliography

[1] Michael E Peskin and Daniel V Schroeder An Introduction to Quantum FieldTheory Addison-Wesley 3 edition 1951 (Cited pages 1 et 7)

[2] C A Baker D D Doyle P Geltenbort and others Improved Experimental Limiton the Electric Dipole Moment of the Neutron Phys Rev Lett 97(13)131801September 2006 [link] (Cited page 4)

[3] SM Barr A review of CP violation in atoms International Journal of ModernPhysics A 08(02)209ndash236 January 1993 [link] (Cited page 4)

[4] C Patrignani K Agashe G Aielli and others Review of Particle PhysicsChinPhys C40100001 October 2016 [link] (Cited pages 4 5 7 54 56 58et 105)

[5] E Eichten K Gottfried T Kinoshita and others Charmonium The model PhysRev D 17(11)3090ndash3117 June 1978 [link] (Cited page 6)

[6] Gerardrsquot Hooft Symmetry Breaking Through Bell-Jackiw Anomalies PhysRevLett378ndash11 1976 (Cited page 10)

[7] S P Klevansky The Nambu-Jona-Lasinio model of quantum chromodynamics RevMod Phys 64649ndash708 1992 (Cited pages 10 et 12)

[8] P Costa C A de Sousa M C Ruivo and others The QCD critical end pointin the SU(3) NambundashJona-Lasinio model Physics Letters B 647(5)431ndash435 April2007 [link] (Cited page 10)

[9] J Stachel and G R Young Relativistic Heavy ION Physics at CERN and BNLAnnu Rev Nucl Part Sci 42(1)537ndash597 December 1992 [link] (Cited page 13)

[10] H R Schmidt and J Schukraft The physics of ultra-relativistic heavy-ion collisionsJ Phys G Nucl Part Phys 19(11)1705 1993 [link] (Cited page 13)

[11] RHIC Physics of the Relativistic Heavy Ion Collider 2017 [httpswwwbnlgovrhicphysicsasp] (Cited page 13)

[12] CERN Heavy ions and quark-gluon plasma [httpshomecernaboutphysicsheavy-ions-and-quark-gluon-plasma] (Cited page 13)

[13] ALICE Collaboration φ-meson production at forward rapidity in p-Pb collisionsat radicsNN = 502 TeV and in pp collisions at

radics = 276 TeV Physics Letters B

768203ndash217 May 2017 [link] (Cited pages 14 15 et 26)

[14] Michael L Miller Klaus Reygers Stephen J Sanders and others Glauber Model-ing in High-Energy Nuclear Collisions Annu Rev Nucl Part Sci 57(1)205ndash243October 2007 [link] (Cited page 14)

vi

Merci agrave Jean-Philippe Perrillat Jean-Franccedilois Gonzalez et Laurent Ducroux pour mrsquoavoirpris dans leur eacutequipe drsquoenseignement cela a eacuteteacute une expeacuterience tregraves enrichissante

I would like to thank all the ALICE collaboration that allowed me to do this thesisand especially I thank all the collaborators who contributed at the lmmumu PAG inparticular Alessandro Di Falco and Ester Casula from the INFN of Cagliari for theirhelp and advice given during the thesis Satoshi Yano from the Hiroshima university forhis contribution of the pp at 13 TeV In addition to the PAG collaborator I would liketo thanks all the DQ people and in particular Diego Laurent Aphecetch and PhilippePillot for their help in the evaluation of the muon arms systematics Martino for all theenriching exchanges on the operation of the ALICE trigger system and the luminosityEvgeny for his response concerning the physics selection and David for the response onthe multiplicity evaluation I would like to thanks Andreas Elena and Marie qualityassurance coordinator with whom I was in contact for my service task for their kindnessand efficiency during the two and a half years or I participated in the QA as well as fortheir understanding on the delays

Cette thegravese mrsquoa permis de mrsquoimmerger dans la communauteacute franccedilaise de la physiquehadronique notamment gracircce aux rencontre QGP France et je voudrais remerciertoutes les personnes avec qui jrsquoai pu avoir de bonnes discussions lors de ces rencontresnotamment les doctorants et post-doc que jrsquoai pu rencontrer Antoine Astrid AudreyBenjamin Emilie Gabriel Gabriele Jana Julien Lucile Maxime Michael et MohamadCette thegravese mrsquoa permis aussi de faire des rencontres enrichissantes durant les diverseseacutecoles que jrsquoai reacutealiseacutes et je souhaiterai remercier les doctorants qui y ont participeacute pourles bons moments passeacutes dans ces diverses eacutecoles

Bien sucircr je souhaite aussi remercier les doctorants qui ont cocirctoyeacute lrsquoIPNL durant cestrois anneacutees notamment Alexandre Biguet Anne-Laure Bertrand Ceacutecile Elvire Eme-line Franccedilois Guillaume Garilot Guillaume Victor Jean-Baptiste Joffrey Lola NicolasBaillot Nicolas Deutschmann Nicolas Galy Pierre Becker Reacutemi et Solegravene En plus desdoctorants que jrsquoai cocirctoyeacutes je souhaiterai aussi remercier Alain Cleacutement David GeoffreyHubert Martin Sylvie et Yoan pour les nombreuses pauses cafeacute pris ensemble durant cestrois anneacutees ainsi qursquoAntoine pour avoir accepteacute drsquoecirctre mon parrain pour ma thegravese

Merci aussi agrave Aureacutelie Camille Eacuteloiumlse Florian et Laurine pour tous les bons momentsque ce sois les midis en soireacutee durant des films ou des sessions jeux Merci aussi agrave Clairepour toutes ces discussions et soutiens mutuel pour nos thegraveses malgreacute le deacutecalage entrela France et le Breacutesil

Enfin jrsquoaimerais remercier ma famille pour leur soutiens durant toute ma formationuniversitaire ainsi que durant ma thegravese Je suis sucircr que mes grands-parents paternel auraieacuteteacute tregraves fiegravere de me voir arriver jusqursquoagrave ce diplocircme eux qui eacutetaient inquiets de savoir sijrsquoy arriverai ainsi que Christian et Thierry mes oncles auraient eacuteteacute fiegravere et auraient aimeacuteme voir agrave ce niveau

Reacutesumeacute

Ce manuscrit sur mon travail de thegravese commence par un premier chapitre sur les motiva-tions physiques du sujet eacutetudieacute tant sur le plan theacuteorique qursquoexpeacuterimental Dans le deux-iegraveme chapitre je traiterai du collisionneur de particules ayant produit les collisions danslrsquoexpeacuterience ALICE utiliseacutees durant lrsquoanalyse preacutesenteacutee dans ce manuscrit La secondepartie de ce chapitre est justement deacutedieacutee agrave lrsquoappareillage ALICE Le troisiegraveme chapitreporte sur la caracteacuterisation du jeu de donneacutees que jrsquoai exploiteacute ainsi que sur lrsquoeacutevaluationde la luminositeacute inteacutegreacutee correspondant agrave cet eacutechantillon Le quatriegraveme chapitre quant agravelui porte sur les simulations Monte-Carlo qui ont du ecirctre faites pour mener agrave bien cetteanalyse Le cinquiegraveme chapitre sur la meacutethodologie utiliseacutee pour extraire de nos don-neacutees les signaux drsquointeacuterecirct Dans lrsquoavant-dernier chapitre le sixiegraveme nous traiterons delrsquoeacutevaluation des quatre sources de systeacutematiques qui impactent notre analyse Le dernierchapitre traitera des reacutesultats que nous avons pu obtenir en termes de sections efficacesde production de meacutesons neutres leacutegers

Cadre Physique (chapitre 1)Le cadre theacuteorique englobant le travail preacutesenteacute dans ce document est la chromodynamiquequantique deacutecrivant lrsquointeraction forte lrsquoune des quatre interactions fondamentales quenous connaissons agrave lrsquoheure actuelle agissant sur les quarks et les gluons par eacutechangede gluons On verra que cette theacuteorie peut srsquoexprimer matheacutematiquement en termes dedensiteacute Lagrangienne De ce Lagrangien peut ecirctre extraite une symeacutetrie particuliegraverementinteacuteressante pour lrsquoeacutetude des meacutesons leacutegers neutres la symeacutetrie chirale qui sera traiteacutee endeacutetails dans ce chapitre introductif De la chromodynamique quantique peut ecirctre extraitun diagramme thermodynamique de la matiegravere hadronique dans lequel deux principalesphases sont visibles la phase ougrave la matiegravere hadronique se condense sous forme de hadronset la phase partonique ougrave est creacuteeacute un plasma de quarks et de gluons (QGP)

Expeacuterimentalement ce diagramme de phases peut ecirctre eacutetudieacute gracircce agrave des acceacuteleacuterateursde particules permettant de faire des collisions cible fixe etou en mode collisionneurDans la seconde partie de ce chapitre je commencerai par introduire quelques variablescineacutematiques drsquointeacuterecirct pour le domaine ainsi que deux concepts geacuteomeacutetriques qui sont lacentraliteacute de la collision deacutetermineacutee par la distance qui seacutepare les centres des deux noyauxet le plan de reacuteaction de la collision Une collision entre deux noyaux comporte plusieurseacutetapes chronologiques notamment la phase de QGP suivie par deux phases hadroniquesdomineacutees respectivement par des collisions ineacutelastiques et eacutelastiques cela engendre desproductions de particules tregraves diverses Dans la suite du chapitre seront parcourus tousles types de sondes inteacuteressantes pour lrsquoeacutetude des collisions drsquoions lourds jrsquoen profiteraipour faire un petit eacutetat de lrsquoart des mesures faites dans les diffeacuterentes voies drsquoobservationBien sucircr les reacutesultats montreacutes le sont seulement agrave titre drsquoexemple et pas de maniegravereexhaustive

La derniegravere section sur les reacutesultats expeacuterimentaux est focaliseacutee sur la productionde dimuons de basses masses dans ALICE qui fait lrsquoobjet de lrsquoeacutetude rapporteacutee dans ce

viii

manuscrit Dans les preacuteceacutedentes eacutetudes lrsquoaccent eacutetait mis sur le meacuteson φ qui est agrave lrsquooriginedu signal le plus facilement observable dans la reacutegion des basses masses Dans notre caslrsquoeacutetude a eacuteteacute porteacutee sur les meacutesons η ρω et φ car la statistique disponible dans le lotde donneacutees eacutetudieacute est suffisante pour extraire les signaux correspondants

LHC et ALICE (chapitre 2)La premiegravere partie du chapitre 2 sera consacreacutee au LHC notamment au complexedrsquoacceacuteleacuterateurs permettant drsquoinjecter au sein du LHC des noyaux ou des protons Onen profitera pour eacutevoquer les sceacutenarios futurs agrave relativement court terme pour le LHC etpour finir cette courte partie les programmes drsquoions lourds au CERN et plus geacuteneacuteralementdans le monde

La seconde partie du chapitre est deacutedieacutee au deacutetecteur ALICE Cette partie peut ecirctregrossiegraverement coupeacutee en deux parties la premiegravere deacutedieacutee au deacutetecteur actuel et son fonc-tionnement la seconde au programme drsquoameacutelioration qui doit deacutebuter agrave la fin du Run 2du LHC

Luminositeacute et Jeu de Donneacutees (chapitre 3)Dans ce chapitre deux points seront eacutevoqueacutes Le premier porte sur les conditions expeacuteri-mentales pour les donneacutees proton-proton agrave 13 TeV prises en 2016 utiliseacutees dans lrsquoanalysedeacutecrite dans ce manuscrit Le second porte sur lrsquoeacutevaluation de la luminositeacute inteacutegreacuteeCette mesure nous permet drsquoeacutevaluer des sections efficaces de production agrave partir des tauxde production connaissant la section efficace associeacutee agrave la condition de deacuteclenchement debiais minimal de lrsquoexpeacuterience et le nombre drsquoeacuteveacutenements de biais minimal eacutequivalent aujeu de donneacutees consideacutereacute dans lrsquoanalyse Ce chapitre ne traitera pas de lrsquoeacutevaluation decette section efficace de biais minimal qui fait lrsquoobjet drsquoune eacutetude agrave part entiegravere non dis-cuteacute dans ce manuscrit et qui sert agrave toutes les analyses Cette section traitera en deacutetailsde la proceacutedure permettant drsquoavoir le facteur de conversion entre le nombre drsquoeacuteveacutenementsanalyseacutes et le nombre eacutequivalent drsquoeacuteveacutenements de biais minimal

Simulations Monte-Carlo (chapitre 4)Ce chapitre est structureacute en deux parties la premiegravere se focalisant sur les meacutesons neutresleacutegers et la deuxiegraveme sur les simulations des processus de charme et beauteacute ouverte

Dans la partie sur les meacutesons on commencera par donner quelques geacuteneacuteraliteacutes surces particules ainsi que sur le geacuteneacuterateur employeacute dans les simulations Puis on traiteradeux cas drsquointeacuterecirct Le premier cas concerne les processus faisant intervenir trois particulesdans lrsquoeacutetat final de la deacutesinteacutegration (deacutesinteacutegration Dalitz) en mettant lrsquoaccent sur leurfacteur de forme Le second cas quandt agrave lui correspond aux deacutesinteacutegrations agrave deuxcorps dans les canaux dileptoniques et plus particuliegraverement dans celui dimuonique

La seconde partie du chapitre est consacreacutee aux dimuons venant des deacutesinteacutegrationsdes saveurs lourdes ouvertes Un dimuon venant des saveurs lourdes ouvertes est deacutefini

ix

comme deux muons produits durant les chaicircnes de deacutesinteacutegration drsquoune paire quark anti-quark charmeacutes ou beaux On verra dans cette section qursquoun impact visible sur le spectreen masse deacutecoule de la distribution cineacutematique initiale du quark beau ou charmeacute gracircceaux comparaisons que nous avons faites avec des simulations utilisant les distributionscineacutematiques de PYTHIA6 et de FONLL Le dernier point eacutevoqueacute dans ce chapitre concernela longueur de chaicircne de deacutesinteacutegration des hadrons charmeacutes et beaux car nous sommesinteacuteresseacutes agrave reproduire les dimuons venant des paires de charme ou de beauteacute qui sontcorreacuteleacutes Une hypothegravese que nous pouvons faire est que plus une chaicircne de deacutesinteacutegrationest longue plus la correacutelation reacutesultante de la paire est amoindrie On montrera que leprofil de longueur de chaicircne de deacutesinteacutegration possegravede une structure relativement complexeet qursquoil y a un impact sur le spectre en masse en ne consideacuterant qursquoun certain intervallede longueur de deacutesinteacutegration

Extraction du Signal (chapitre 5)Dans ce chapitre deux points seront eacutevoqueacutes le premier sera lrsquoeacutevaluation et la soustractiondu bruit combinatoire le second portera sur la proceacutedure utiliseacutee pour extraire le signal

La composante de bruit combinatoire dans les dimuons de signes opposeacutes aussi appeleacutebruit non-correacuteleacute provient de la meacutethode de construction des dimuons Cette meacutethodeneacutecessite la creacuteation de toutes les paires de dimuons possibles dans un eacuteveacutenement Poureacutevaluer cette composante nous employons la technique du mixage drsquoeacuteveacutenements crsquoest-agrave-dire que nous creacuteons agrave lrsquoaide des donneacutees un lot de dimuons qui par construction serontnon-correacuteleacutes en formant chaque dimuon par combinaison drsquoun muon drsquoun eacuteveacutenement avecun muon drsquoun autre eacuteveacutenement La distribution ainsi obtenue est normaliseacutee agrave partir desdistributions de dimuons de mecircmes signes Cette proceacutedure agrave eacuteteacute valideacutee agrave lrsquoaide desimulations Monte-Carlo Une fois la soustraction du bruit faite pour chaque intervalleen pT et y consideacutereacute dans notre analyse nous pouvons passer agrave lrsquoextraction du signal

Pour extraire le signal drsquointeacuterecirct de notre spectre de dimuons correacuteleacutes nous utilisonsune proceacutedure drsquoajustement par minimisation du χ2 Cette proceacutedure est baseacutee sur unefonction servant agrave lrsquoajustement qui est composeacutee des distributions en masse des pro-cessus hadroniques composant notre cocktail hadronique Nous verrons notamment parquel moyen nous arrivons agrave reacuteduire le nombre de degreacutes de liberteacute de notre fonction enasservissant certaines composantes agrave drsquoautres Une grande partie de ce point est consacreacuteeau traitement du continuum correacuteleacute et aux meacutethodes permettant de deacutecrire la forme dela fonction modeacutelisant le continuum correacuteleacute

Eacutevaluation des Systeacutematiques (chapitre 6)Ce chapitre est diviseacute en quatre parties une pour chaque contribution agrave la systeacutematiquede notre analyse

La premiegravere partie traitera de la systeacutematique sur lrsquoextraction du signal et notammentsur lrsquoeacutevaluation de la systeacutematique sur tous les choix que nous avons faits pour reacutealisernotre ajustement Pour cela un ou plusieurs tests sont faits en modifiant agrave chaque foisun seul paramegravetre par rapport agrave notre ajustement de reacutefeacuterence Une fois tous les tests

x

reacutealiseacutes pour un intervalle en pT-y consideacutereacute dans cette analyse on eacutevalue par la meacutethodede deacuteviation standard lrsquoerreur systeacutematique qui en reacutesulte

Les autres parties traiteront de la systeacutematique lieacutee agrave lrsquoestimation du produit delrsquoacceptante geacuteomeacutetrique et de lrsquoefficaciteacute de reconstruction notamment le choix de lrsquoinputcineacutematique pour les simulations Monte-Carlo lrsquoincertitude sur lrsquoefficaciteacute du systegraveme dedeacuteclenchement et sur lrsquoefficaciteacute du systegraveme de trajectographie

Reacutesultats (chapitre 7)Dans ce dernier chapitre avant de parler des reacutesultats nous discuterons la correction dusignal extrait des distributions de masse invariante reconstruit pour lrsquoestimation de lasection efficace de production Nous passerons ensuite aux reacutesultats en preacutesentant et endiscutant la deacutependance en pT et y de la section efficace de production des meacutesons ηρω et φ Les reacutesultats obtenus dans cette analyse seront compareacutes aux preacutedictions desmodegraveles PYTHIA et PHOJET et aux reacutesultats disponibles dans ALICE agrave drsquoautres eacutenergies

Table of contents xi

Table of contents

1 Physics Motivations 111 Theoretical Baseline 1

111 Quantum ChromoDynamics (QCD) 3112 Chiral Symmetry 6113 Hadronic Matter mdash Quark-Gluon Plasma (QGP) 11

12 Heavy-Ion Physics Experimental Program 12121 Relevant Kinematic Variables 13122 Collision Geometry 14123 Evolution of a Heavy-Ion Collision 15124 Experimental Observables of the QGP 16125 Proton-Proton Collisions 22

13 Low-Mass Dimuon Measurements in ALICE 23

2 ALICE at the CERN LHC 2921 The Large Hadron Collider 29

211 The CERN accelerator complex 29212 The LHC schedule 30213 The Experimental Heavy-Ion Program 32

22 A Large Ion Collider Experiment (ALICE) 33221 The Central Barrel 34222 The Forward Detectors 36223 The Muon Spectrometer 38224 The ALICE software framework 40225 The ALICE Upgrade 41

3 Data Sample Selection and Integrated Luminosity Evaluation 4531 Data Sample Event and Track Selection 4532 Integrated Luminosity Evaluation 46

321 F inorm Calculation 47

322 The MB Trigger Cross Section 50323 Lint Evaluation 51

4 Monte Carlo Simulations 5341 Light-Meson Decays 53

411 Kinematical Distributions 54412 Dalitz Decays 54413 Two-Body Decays 57

42 Dimuons from Open Heavy-Flavor Decays 60421 PYTHIAndash FONLL Comparison 61422 Decay Chain Length in the Open Heavy-Flavor Processes 62

xii Table of contents

5 Signal Extraction 6551 Combinatorial Background Evaluation and Subtraction 65

511 The Event Mixing Technique 66512 Monte Carlo Validation of the Event Mixing Technique 67513 The Combinatorial Background Estimation 68

52 Invariant Mass Fit Procedure 70521 Specific Constraints on the Hadronic Cocktail Components 71522 Correlated Continuum Treatment 72523 A Few Examples of Hadronic Cocktail Fits 76

6 Systematics Evaluation 7961 Systematics on the Signal Extraction 80

611 Relative Branching Ratio of two-body and Dalitz Decays for the ηand ω Mesons 80

612 σηprimeσφ Cross-Section Ratio 80613 σρσω Cross-Section Ratio 81614 Upper limit of the fit 81615 The correlated continuum shape 81616 Systematic Uncertainty Computation 82

62 Systematics from the MC input 8263 Systematics on Trigger Efficiency 83

631 Evaluation of the Trigger Response Function 83632 Results 84

64 Systematics on Tracking Efficiency 85641 Preliminary Check 85642 Tracking Efficiency Evaluation 86643 MC parametrization 88644 Results 89

65 Summary of Systematic Uncertainty 89

7 Light Neutral Meson Production 9171 Estimation of the Number of Generated Mesons 91

711 The Two-Body Decay Case 91712 The Dalitz Decay Case 92

72 Cross-Section Production for Light Neutral Mesons 93721 Double-Differential η Meson Production 93722 ρω Meson Production 94723 Double-Differential φ Meson Production 98

Conclusions 105

A List of Runs 107

B Raw-Background Comparison mdash figures 111

C Hadronic-Cocktail fits mdash figures 123

Table of contents xiii

Bibliography 135

Chapter 1

Physics Motivations

Summary11 Theoretical Baseline 1

111 Quantum ChromoDynamics (QCD) 3112 Chiral Symmetry 6113 Hadronic Matter mdash Quark-Gluon Plasma (QGP) 11

12 Heavy-Ion Physics Experimental Program 12121 Relevant Kinematic Variables 13122 Collision Geometry 14123 Evolution of a Heavy-Ion Collision 15124 Experimental Observables of the QGP 16125 Proton-Proton Collisions 22

13 Low-Mass Dimuon Measurements in ALICE 23

11 Theoretical BaselineThe theoretical framework underlying the subject of the present thesis is the StandardModel of particle physics (SM) The SM gathers the theories describing the electromag-netic weak and strong interactions as well as Higgs sector providing at the same timea classification of all the subatomic particles known in terms of matter constituents andgauge bosons see figure 11 It was developed throughout the latter half of the 20th cen-tury the current formulation having been finalized in the mid-1970s upon experimentalconfirmation of the existence of quarks Since then discoveries of the Wplusmn and Z0 bosons(1983) the top quark (1995) the tau neutrino (2000) and the Higgs boson (2012) havegiven further credence to the Standard Model [1]

Each elementary interaction in the SM is characterized by an interaction range anda set of gauge bosons carrying the interaction charge It should be noted that the SMdescribes the weak and electromagnetic interactions as two different aspects of a singleelectroweak interaction

bull The weak interaction has a very small range of the order of 10minus18 m and is medi-ated by the Z0W+ and Wminus bosons This interaction affects all known elementaryfermions

2 Chapter 1 Physics Motivations

bull The electromagnetic interaction is characterized by an infinite range and affectsany particle having a non-zero electric charge The associated gauge boson is thephoton

bull The strong interaction acts at small distances having a range of the order of 10minus15 mat this range the strong interaction dominates over the other elementary interac-tions The strong interaction is mediated by the exchange of massless gauge bosonscalled gluons that interact with quarks anti-quarks and other gluons via a chargecalled color charge The theoretical framework for the strong interaction is givenby the theory of Quantum Chromodynamics described in more details in the nextsection

12e neutrino

νe

minus1

12

510999 keV

electron

e

RGB23

12

22+06minus04 MeV

up

uRGB

minus13

12

47+05minus04 MeV

down

d

12micro neutrino

νmicro

minus1

12

105658 MeV

muon

micro

RGB23

12

127 plusmn 003 GeV

charm

cRGB

minus13

12

96+8minus4 MeV

strange

s

12τ neutrino

ντ

minus1

12

177686 plusmn 016 MeV

tau

τ

RGB23

12

160+5minus4 GeV

top

tRGB

minus13

12

418+004minus003 GeV

bottom

b

plusmn1

1

80385 plusmn 0015 GeV

Wplusmn1

911876 plusmn 00021 GeV

Z

1photon

γ

color

1gluon

g0

12509 plusmn 024 GeV

Higgs

Hst

rong

inte

ract

ion

elec

trom

agne

ticin

tera

ctio

n

weak

inte

ract

ion

6qu

arks

(+6

anti-

quar

ks)

6le

pton

s(+

6an

ti-le

pton

s)

12 fermions(+12 anti-fermions)

13 bosons

Matter Constituents Gauge BosonsGoldstone

bosons

1st 2nd 3rd generation

1

Figure 11 Standard Model of particle physics and the different families of matter

11 Theoretical Baseline 3

111 Quantum ChromoDynamics (QCD)The Quantum ChromoDynamics (QCD) is the theory describing the hadronic physicsphenomena in the framework of the SM For this reason QCD is needed to correctlydescribe and interpret the observations in experiments involving high-energy hadronicinteractions like ALICE at the LHC

The color charge of the QCD can have three different values (red green and blue) aswell as the corresponding anti-colors This determines a part of the mathematical struc-ture of QCD based on the special unitary group of degree 3 mdash the Lie group SU(Nc=3)cThe complete mathematical structure of QCD is based on the Lorentz group L = SO(1 3)for the space-time transformations (gluons are in the vector representation and quarksin the spinor one) a gauge symmetry SU(Nc = 3)c an approximate light flavor symme-try SU(Nf = 3)f (this symmetry is not relevant even approximately for the remaining3 heavy flavors) The introduction of a three-color charge allowed at the beginning ofthe development of the QCD for the reconciliation of the observation of the spin-3

2 ∆++

baryon composed of three up quarks in the same spin state with the Pauli exclusionprinciple

The QCD Lagrangian LQCD

In the Quantum Field Theory formalism of particle physics any theory can be expressedin terms of a Lagrangian The mathematical expression of the Lagrangian density ofQCD1 is

LQCD =flavorssumf

qc1f (ipartmicroγmicroδc1c2 minusmfδc1c2) qc2

f

+flavorssumf

qc1f gsA

amicrotac1c2γ

microqc2f minus

14G

microνa G

amicroν + LCP

(11)

(Besides the explicit flavor summation each index when repeated twice indicates asummation on this index) In equation (11) micro ν are Minkowski indexes ranging from 0to 3 the qcf spinor represents the quark field of flavor f and color c (the Dirac index ofquark fields and γ-matrices are not written explicitly for convenience) mf is the massof a quark of flavor f gs is linked to the coupling constant of the theory αs = g2

s4π(after quantification and renormalization αs becomes a running coupling constant alsoquantification requires the introduction of ghost fields) the gluon fields Aamicro are Lorentzvectors Gmicroν

a is the gluon strength tensor and the ta matrices (generators of SU(Nc=3)c)are defined after the Gell-Mann matrices ta = λa2

The first term of LQCD

Lfree q =flavorssumf

qc1f (ipartmicroγmicroδc1c2 minusmfδc1c2) qc2

f = q (ipart minus mf ) q (12)

is a free Lagrangian representing the propagation of free quarks m representing thediagonal quark mass matrix

1 By language abuse the QCD Lagrangian density is simply named QCD Lagrangian

4 Chapter 1 Physics Motivations

The second term

Lint =flavorssumf

qc1f gsA

amicrotac1c2γ

microqc2f = gsqAq (13)

encodes the minimal (or Yukawa) coupling describing the interaction of the quark fieldswith the gluons

The third term of LQCD involvesGamicroν the gluon strength tensor which can be expressed

asGamicroν = partmicroA

aν minus partνAamicro + gsf

abcAbmicroAcν (14)

The fabc coefficients are the structure constants of SU(3) The first part of the tensor inequation (14) partmicroAaν minus partνA

amicro describes the gluon kinematics in analogy to the kinematics

description of photons in quantum electrodynamics (QED) The last term gsfabcAbmicroA

cν is

specific to QCD and describes the gluon auto-coupling due to the fact the QCD is anon-Abelian theory

The last term in equation (11) LCP is related to a possible violation of the CP-symmetry (due to a breaking of T symmetry and the conservation of the CPT symmetry)in the QCD sector This term is defined as

LCP = θg2s

32π2 GamicroνG

microνa (15)

where G is the dual of GGamicroν = 1

2εmicroναβGαβa (16)

and εmicroναβ is the antisymmetric Levi-Civita pseudo-tensor The θ parameter which wouldtake a non-zero value in case of CP-violation of LQCD can be experimentally accessed bymeasuring the electric dipole momentum of the neutron Its value compatible with zerois currently not explained by the theory [2 3]

The QCD Running Coupling Constant αs

By using the perturbative-QCD (pQCD) and the renormalization group equation [4] it ispossible to extract a running coupling constant αs depending on the momentum transferQ and on a parameter ΛQCD establishing the scale at which the perturbatively-definedcoupling would diverge At first order of perturbation theory αs can be expressed as

αs(Q2) = 12π

(11Nc minus 2Nf ) ln(

Q2

Λ2QCD

) (17)

where Nc is the number of colors (3) Nf is the number of light flavors respecting mq Q

and ΛQCD asymp 200 MeVFigure 12 shows the excellent agreement between available measurements of αs(Q2)

and the pQCD theoretical prediction beyond first order According to the value of thetransfer momentum Q two regimes of QCD can be defined for values of the transfermomentum Q above Q asymp 1 GeV (of the order of the nucleon mass) implying Q ΛQCD(or for distances well below 1 fm corresponding to the nucleon size) QCD is in the regime ofasymptotic freedom for Q 1 GeV QCD behavior is dominated by the color confinementmechanism

11 Theoretical Baseline 5

Figure 12 Summary of measurements of αs as a function of the momentum transfer Q and thepQCD prediction [4]

Asymptotic Freedom

In the large momentum transfer region Q ΛQCD or at small distance the decreasingof the coupling constant αs reflects the fact that the particles interacting over shortdistances 1 fm (the typical size of the nucleon) can be treated asymptotically as quasi-free particles This allows one to use a perturbative approach in performing calculationsbased on series of αs powers Let us notice that asymptotic freedom does not mean thatquarks are not interacting at all in high-energy collisions (the freedom is only asymptotic)Indeed it has been shown that at RHIC energy a strongly interacting QGP (s-QGP) iscreated

Color Confinement

Figure 13 Sketch of twoquark separation

In the small momentum transfer region or large distancethe coupling constant perturbatively diverges The physicalinterpretation for this phenomenon is the color confinementA schematic explanation of this phenomenon is the followingif it was possible to hold two color charges (for example twoquarks) and pull them part the energy density would con-centrate into a flux tube due to the non-Abelian characteris-tics of QCD (differently to QED) The energy would increasewith the separation until it reaches a threshold above whichpair creation is possible Figure 13 sketches this effect known as string breaking This isthe reason why in vacuum it is not possible to observe directly one isolated quark and allof them are found in composite particles named hadrons the color charge of hadrons iszero (hadrons are ldquocolorlessrdquo or ldquowhiterdquo) as the colored flux tube wraps within the hadronitself and can be observed

6 Chapter 1 Physics Motivations

A simple modelisation of the potential V (r) between two quarks is given by the Cornellpotential [5]

V (r) = minusαsr

+ σr (18)

In equation (18) the first term models the asymptotic freedom with a Coulomb potential(this term is dominating at r rarr 0) and the second term (dominating when r rarr infin) iscalled the string potential with the string tension σ sim (260 MeV2)

Hadrons can be classified as

bull mesons composed of one quark and one anti-quark

bull baryons composed of three quarks

bull exotic states like the recently observed tetra-quark etc

112 Chiral SymmetryThe chiral symmetry is one of the two fundamental symmetries of QCD governing low-energy QCD (low-hadronic masses) and the properties of the transition between the par-tonic and the hadronic phases observed in heavy-ion collisions

The chiral symmetry can be conveniently introduced and discussed considering theway Lorentz transformations act on bosons and fermions To start this discussion let usconsider a massless universe To understand the properties of the Lorentz transformationof any quantum state one can decompose it into its fundamental building blocks calledchiral fermions χR (the right chiral fermion) and χL (the left chiral fermion) PhysicallyχR and χL are spinor fields (spin frac12) and the R and L indices denote the helicities ofthe states In a massless universe the helicity is a good quantum number there is noLorentz transformation that can change the ldquoorientationrdquo of the spin hence for any inertialobservers the measured helicity would be the same Since χR and χL are fundamentalstates when Lorentz transformations are considered one can build any spin state bymixing these building blocks mathematically the Lorentz group can then be describedas a SU(2)RotimesSU(2)L group whose fundamental representations2 are χR and χL

Let us now consider a massive fermion state obviously now two observers with differ-ent speed relative to the fermion will measure different projections of the spin along themomentum of the particle the helicity is no more a good quantum number The chiralfermions χR and χL can now transform into one another this mechanism is called thebreaking of the chiral symmetry As anticipated in the introduction of this section thissymmetry is crucial to understand the low-mass sector of QCD since it is dominated byhadronic states composed of almost massless quarks (namely u d s composing the light

2 To see why the SO(13) Lorentz group L can be described by the combination of two SU(2) groupsone has to remember that L contains three rotations (that gives one SU(2) group) and three boosts (thatcan be seen as rotation involving the time direction and an imaginary angle that gives another SU(2)group) Those two algebras are not independent (eg boost and rotation do not commute) but they canbe decoupled into SU(2)RotimesSU(2)L independent algebras

11 Theoretical Baseline 7

neutral meson studied in this thesis) compared to the typical scale of QCD ΛQCD (seetable 11)

u m = 22+06minus04 MeVc2 c m = 127plusmn 003 GeVc2 t m = 160+5

minus4 GeVc2

d m = 47+05minus04 MeVc2 s m = 96+6

minus4 MeVc2 b m = 418+04minus03 GeVc2

Table 11 Quark masses [4]

In the following we will explain with a very simple quark model some observablephenomena linked to the fundamental QCD chiral symmetry the non observation ofdegeneration in mass between the scalar and pseudo-scalar octet as well as the spontaneouschiral symmetry breaking related to the phase transition observed eg in LHC arounda temperature of 170 MeV

a A Lagrangian for a free massless quark

For one chiral quark χR the free Lagrangian is3

Lfree qR = iχdaggerRpart0χR + iχdaggerRminusrarrσ middotminusrarrpart χR (19)

the form of the Lagrangian being dictated by the usual constraints (Lorentz invariancehermiticity conservation laws) but for one quark flavor the state with opposite helicityalso exists in nature for one quark flavor one can write Lfree q = Lfree qR + Lfree qLThis can be conveniently written

Lfree q = qipartq (110)

where q is a Weyl spinor (4 component spinor)

q =[χRχL

] (111)

and the usual notation q = qdaggerγ0 (see chapter 32 of [1])

b Explicit breaking of the chiral symmetry in presence of a mass term

The Lagrangian of a free quark of mass m is

Lfree q = q (ipart minusm) q = L0 + Lm (112)

This Lagrangian contains a mass term which is explicitly written as

Lm = mqq = m(χdaggerRχL + χdaggerLχR

) (113)

The number of R (L) quarks in this system is given by

NRL = χdaggerRχR(χdaggerLχL

) (114)

3 We do not consider Majorana fermions in this manuscript

8 Chapter 1 Physics Motivations

Let us define a transformation belonging to the symmetry group U(1)RotimesU(1)L

χR rarr eiθR χR

χL rarr eiθL χL

Lfree q rarr L0 +m(ei(θLminusθR) χdaggerRχL + ei(θRminusθL) χdaggerLχR

) (115)

this symmetry is broken by the mass term as discuss previously when considering thecase of the boost of a massive fermion the number of R or L quarks is not the samefor all observers However this symmetry restricted to the case of θR = θL equiv θV is notbroken and is associated to the conservation of the fermion number This result in theUV (1) symmetry

q rarr eiθV q lArrrArr[χRχL

]rarr eiθV

[χRχL

] Lfree q rarr Lfree q (116)

The V stands for Vector (it is the conservation of the so-called vector current V micro = qγmicroq)For further convenience we also define UA(1) as the symmetry group with transformationgiven by θR = minusθL equiv θA the A stands for Axial (a transformation in UA(1) is thus givenby q rarr eiθAγ5 q)

c For more than one flavor

Finally let us consider the Lagrangian of a system composed by the two lightest flavorsu and d giving Nf = 2 (but this discussion could also be extended to a system includinga third flavor s light enough compared to ΛQCD)

Lfree light q = iqupartmicroγmicroqu + iqdpartmicroγ

microqd minusmuququ minusmdqdqd (117)

In this case one can introduce for convenience the iso-spinor ψ =(quqd

)

Lfree light q = ψ (ipart minus m0)ψ (118)

= iψpartmicroγmicroψ minus mu +md

2 ψψ minus mu minusmd

2 ψτ3ψ (119)

where m0 is the quark masses matrix τ3 is the iso-spin Pauli matrix (noted τ not toconfuse it with σ3 that acts on spinor index) For convenience let us also use

ψR equiv[quRqdR

]equiv

quR0qdR0

equiv PRψ (120)

wherePR = 1 + γ5

2 (121)

and the same for ψL wherePL = 1minus γ5

2 (122)

11 Theoretical Baseline 9

The symmetry we discussed in paragraph b is extended by adding a mixing ofthe flavor states This is what is usually called in the literature ldquochiral symmetryrdquoSUR(Nf )timesSUL(Nf )

The iso-spinor ψ = ψR + ψL transforms under the chiral symmetry as

ψ rarr eiminusrarrθR middotminusrarrt ψR + ei

minusrarrθL middotminusrarrt ψL (123)

where minusrarrt = ~τ

2 and minusrarrθRminusrarrθL isin (R3)2

As in the one flavor case the kinetic term

Lk = iψLpartmicroγmicroψL + iψRpartmicroγ

microψR (124)

is chiral invariant while the mass term is not However when the mass difference is zero(the so-called exact isospin limit) the SUV (Nf ) symmetry is exact

d The symmetry of the quark sector of QCD mdash the eightfold way

Let us consider only massless quarks (a good approximation for u d and s) giving Nf = 3and the light sector only

LQCD = Lfree light q + Lr (125)

where Lr incorporates the terms appearing in the second line of equation (11) as wellas any term relative to heavy quark Lr transforms trivially or in the same way as aLfree light q For this reason the chiral transformation of LQCD can be studied consideringLfree q only In this massless scenario the largest symmetry group for LQCD can be ex-pressed as G=UR(1)otimesUL(1)otimesSUR(Nf )otimesSUL(Nf ) = UR(Nf )otimesUL(Nf ) A transformationof this group is given by

ψ rarr eiθR t ψR + eiθL t ψL (126)

where t =(1~t

)and θ =

(θ ~θ

) This symmetry would allow one to classify light hadronic

states into double U(Nf = 3) multiplets (one for left-handed and one for right-handed)where scalar and pseudo-scalar members would be invariant under U(Nf = 3) rotationin the flavor space which implies the same mass This is not what is observed Atmost one sees multiplets (approximately) invariant under vector symmetry SUV (Nf = 3)rotation (see paragraph b ) for example the octet of pseudo-scalar mesons π K η andthe decuplet of baryons n p Λ etc

The chiral partner of the cited pseudoscalar meson octet is the scalar octet of the a0κ and σ meson the fact that no degeneracy in mass is observed between the members ofthe pseudoscalar octet and the members of the scalar one is linked to the G symmetrybreaking For convenience one can rewrite G = UR(Nf = 3)timesUL(Nf = 3) as

G = UV (1)otimes UA(1)otimes SUV (3)otimes SUA(3) (127)

where

bull UV (1) is the symmetry already discussed in paragraph b it is the conservation ofthe individual flavor quark number

10 Chapter 1 Physics Motivations

bull UA(1) was also introduced in paragraph b This group should be a symmetry in themassless scenario leading to the observation of mη = mηprime (one should see a nonetinstead of an octet of degenerated pseudoscalar mesons) [6] This is howevernot the case The more generally accepted explanation is that the gluon part Lr

of LQCD generates an explicit breaking of the UA(1) symmetry due to non-zeroquantum fluctuations in the gluon strength tensor sim 〈G2〉

G2 = GmicroνGmicroν (128)

bull SUV (3) this is the observed (approximate) symmetry between the masses of themembers of a multiplet4 This means that the SUV (3) symmetry is good enough toclassify hadronic states this corresponds to ldquothe eightfold wayrdquo

bull SUA(3) this group should be again a symmetry in a massless scenario one wouldthen observe a degeneracy between the scalar and the pseudoscalar meson octetThis is not the case because the chiral symmetry SUV (Nf )otimesSUA(Nf ) is sponta-neously broken (Goldstone mechanism) to SUV (Nf = 3) The π K η are the(almost) massless Goldstone bosons of this mechanism

e Spontaneous breaking of the chiral symmetry and phase transition

The Goldstone mechanism just mentioned when discussing the SUA(3) group can beunderstood in the framework of a quark model the Nambu-Jona-Lasinio model [78] withmassless quarks For two light flavors one has

LNJL = ψ (ipart)ψ +Gs

[(ψψ

)2+(ψiγ5~τψ

)2] (129)

where Gs is a coupling constant for four-quark contact interactions It mimics the shortrange strong interaction as a contact interaction This Lagrangian is chirally invariantsince the interaction term is built from a scalar ψψ and its pseudoscalar counterpart soas to be invariant

If the interaction term is sufficiently large (GsΛQCD2 sim 1) quarks can condense

(〈ψψ〉 6= 0) and equation (129) can be rewritten as

LNJL ψ(ipart + 2Gs〈ψψ〉

)ψ + middot middot middot (130)

The quantity mD equiv minus2Gs〈ψψ〉 acts exactly as a mass term (it is the so-called dynamicalmass) and spontaneously breaks the chiral symmetry

If temperature increases generally there will be a screening of the interaction and〈ψψ〉(T ) = 0 for T gt Tc where Tc is called the phase transition temperature the chiralsymmetry is said to be restored At approximately the same temperature the decon-finement occurs hence the high temperature phase is also known as the Quark GluonPlasma (or QGP) phase The fact that chiral symmetry restoration and deconfinementare occurring at almost the same temperature happens because in low-energy QCD thereis basically one scale only ΛQCD

4 The observed mass differences are not exactly zero because the u d s mass differences are notexactly zero (isospin limit)

11 Theoretical Baseline 11

minusrarrπσ

Ueff

A

B

a

minusrarrπσ

Ueff

b

minusrarrπσ

Ueff

c

1Figure 14 Effective potential as a function of ~πndashσ left to right going towards fully chirality restora-tion

If one takes σ sim ψψ and ~π sim ψiγ5~τψ the chiral symmetry restoration can be describedin the same way as the Goldstone mechanism related to the Higgs mechanism At lowtemperature one has a Goldstone effective potential Ueff (see figure 14 a) that has the well-known Mexican hat shape the ldquovacuumrdquo (relative to the expectation value 〈~π〉 = 0 = 〈σ〉)is in fact unstable The physical vacuum is located at the bottom of the potential on theso-called chiral circle As the temperature increases the chiral circle shrinks until the state〈~π〉 = 0 = 〈σ〉 is stable (see figure 14 c) this is the restoration of the chiral symmetry

The chiral symmetry restoration has an impact on the in-medium spectral functionsof hadrons the most easily accessible experimental observable related to this mechanismis the ρ meson thanks to its short life-time (13 fmc) allowing it to be produced anddecay inside the volume of the QGP typically obtainable in heavy-ion collisions

113 Hadronic Matter mdash Quark-Gluon Plasma (QGP)

As already remarked low-energy QCD mechanisms are driven by the same scale param-eter ΛQCD this is the reason why chiral symmetry restoration and color deconfinementhappen under the same thermodynamical conditions identifiable in the QCD phase dia-gram shown in figure 15

This schematic diagram presents two main regions The first one is the region atlow temperature and density where quarks and gluons are confined inside hadrons andthe chiral symmetry is broken The second region is characterized by large values oftemperature and or net baryon density where the relevant degrees of freedom are quarkand gluon and is a new state of matter the Quark Gluon Plasma (QGP) These tworegions are separated by a phase transition At vanishing net baryonic density (from 0 toan hypothetical critical point) this frontier is a smooth phase (ldquocross-overrdquo) transitionAt increasing value of net baryonic density beyond an hypothetical critical point thefrontier becomes a first order phase transition At extreme values of the net baryonicdensity and low temperature other hadron phases of the hadronic matter can be possibleas the hypothetic color superconducting phase proposed by some theoretical speculations

The only way to get experimental access to the QCD phase diagram in the regionof deconfinement under controlled conditions is to perform ultra-relativistic heavy-ioncollisions Different regions of the phase diagram can be covered by changing the center-

12 Chapter 1 Physics Motivations

Figure 15 Schematic QCD phase diagram as a function of temperature and net baryon density

of-mass energy of the collision as the energy increases the initial temperature of thesystem increases and its net baryonic density decreases At the high-energy frontier theexperiments carried at the Large Hadron Collider (LHC) at CERN and the RelativisticHeavy-Ion Collider (RHIC) at the BNL are suited to reproduce the conditions of hightemperature and low-net baryonic density present in the early Universe

In this QCD phase diagram there is a hypothetical Critical Point and this pointprovides a major research focus both theoretically and experimentally On the theory sidelattice QCD (LQCD) gives accurate results only at zero density It can be extrapolatedat finite density Another technique is the use of effective models as the NJL one [7] Onthe experimental side studies of heavy-ion collisions are done with several energies andion species (NA61 STAR PHENIX) and they probe different density regimes Finallycompact star observation may also give results about the zero temperature high densityphase of QCD

12 Heavy-Ion Physics Experimental ProgramThe experimental study of QGP needs this state of matter to be recreated in laboratoryAs we have seen in the previous section high density andor temperature are needed inorder to reach the conditions for the creation of the QGP state these conditions are metin ultra-relativistic heavy-ion collisions This experimental tool allows one to change theenergy density of the system by varying the size and the energy of the colliding nuclei

12 Heavy-Ion Physics Experimental Program 13

Several probes of the QGP exist which will be described later in this chapter the design ofa heavy-ion detector directly depends on the probes chosen for the experimental program

The relativistic heavy-ion experimental program started in the early 1980s at the BNLAGS [9] and CERN SPS [10] (collision energy per nucleon pair up to radicsNN asymp 20 GeV)and continues today both at the SPS and at the RHIC [11] and LHC [12] colliders whereenergies up to radicsNN = 02 TeV and 5 TeV are reached respectively

121 Relevant Kinematic Variables

Before discussing collision geometry and QGP probes we briefly introduced the mainkinematic variables of interest for heavy-ion physics and particularly for the study pre-sented in this manuscript

Transverse Momentum (pT) The kinematics of a particle can be described by anenergy-momentum quadrivector In the context of a high-energy experiment where aprivileged axis is defined by the beams the 3-momentum can be conveniently decomposedinto its longitudinal (pz) and transverse (pT) components The transverse momentum isinteresting for two reasons firstly the transverse degree of freedom is created during thecollision since the initial state is characterized only by the longitudinal degree of freedomof the colliding particles secondly the transverse momentum is invariant under Lorentzboosts along the z-axis allowing one to directly compare the pT distributions measuredin fixed-target and collider experiments

Rapidity (y) The longitudinal degree of freedom of a particle kinematics can be con-veniently expressed in terms of the rapidity variable y defined as

y = 12 ln

(E + pzcE minus pzc

) (131)

It can be shown that the rapidity is additive under Lorentz boosts along the z-axisthis allows one to directly compare the shape of the rapidity distributions measured infixed-target and collider experiments

Pseudo-Rapidity (η) In the ultra-relativistic regime where p m and E asymp p therapidity can be approximated by the pseudo-rapidity η

y = 12 ln

(E + cp cos θE minus cp cos θ

)asymp 1

2 ln(

1 + cos θ1minus cos θ

)= minus ln

[tan

(θ

2

)]equiv η (132)

The pseudo-rapidity is especially useful whenever the energy and the longitudinal mo-mentum pz are not available at the same time in this case the pseudo-rapidity providesan approximation of the rapidity based on the measurement of the polar angle θ only (theangle between the z-axis and the particle direction)

14 Chapter 1 Physics Motivations

Invariant Mass In case the particle of interest for a given analysis is not directlyobservable (because of its short life time) its kinematics can still be reconstructed byidentifying and measuring its decay products the quadrivectors of the daughters canbe composed to obtain the quadrivector of the mother particle from which can be easilyobtained its invariant massm2c4 = E2minusp2c2 In the specific case of the analysis presentedin this thesis the φ meson (as well as the other low-mass neutral mesons η ρ ω) hasbeen identified through its decay into two muons

122 Collision GeometryTo clearly interpret the observables in a heavy-ion collision one also needs to characterizeits geometry The two main geometric parameters characterizing a heavy-ion collision arethe centrality and the event plane

Centrality mdash The centrality is a concept related to the finite size of the collidingnuclei in fact heavy nuclei (like the lead nuclei accelerated at the LHC) can be regardedas extended objects consisting of several nucleons Some of these nucleons participate tothe collision and are called participants while the remnants do not interact and are calledspectators see figure 16-left

x

y

ΦRP

Figure 16 Schematic representation of a lead-lead collision

As it can be also seen in figure 16-left an impact parameter b can be identified whenlooking at a nucleus-nucleus collision in the transverse plane If this parameter is nullthe overlap between the two nuclei and the energy available in the overlapping volumeis maximal these collisions are classified as most central For larger impact parametersthe overlap region between the two nuclei and the energy available in the overlappingvolume become smaller these collisions are classified as semi-central semi-peripheral andperipheral for increasing values of b If the impact parameter is larger then two nuclearradii the collision is called ultra-peripheral and there is no hadronic interaction betweenthe two nuclei

The impact parameter in a heavy-ion collision is not directly measurable due to itsfemtoscopic size Yet b (so the centrality of the collision) can be estimated by quantifyingthe produced particle multiplicity since the two quantities are strongly correlated [13]An effective way to establish this correlation is provided by the Glauber Model [14]

In smaller collision systems like pp and p-Pb the measurement of the produced parti-cle multiplicity is still possible giving insight into the energy of the partonic interactions

12 Heavy-Ion Physics Experimental Program 15

involved in the collision (the so-called ldquoevent activityrdquo) However due to the loose corre-lation between this quantity and the geometry of the collision in such small systems [13]no geometrical interpretation can be established in this case

Event plane mdash In case the collision is not head-on it is possible to define the eventplane as a plane formed by the beam direction and the impact parameter The transverseprofile of this plane in non-central nucleus-nucleus collisions is represented in the rightpanel of figure 16 The determination of the event plane orientation event-by-event isimportant to characterize the azimuthal anisotropies observed in the measurement of theparticles produced in the collisions

123 Evolution of a Heavy-Ion CollisionFigure 17 illustrates the evolution of the hadronic collision in the two cases where theQGP is created (right side) or not (left side)

Figure 17 Space time evolution left-side without QGP right-side with QGP

Collisions with creation of QGP mdash In this case a dense and hot system of freepartons is created in the collision the typical size of the system is such that a ther-modynamical approach can be adopted and a medium temperature defined This sys-tem of deconfined quarks and gluons undergoes multiple interactions and the expansioncharacterized by a hydrodynamic-like collective expansion During this expansion thehadronization starts and there is a cooling of the system until the critical temperatureof the transition between the partonic and hadronic phases (Tc) is reached The coolingcontinues the medium is a hadronic gas until the temperature of chemical freeze-out(Tch) is reached (from above) beyond this point the inelastic interactions stop and the

16 Chapter 1 Physics Motivations

composition of hadronic species is fixed The cooling continues until the kinetic freeze-outis reached beyond this point the elastic interactions also stop and the hadrons fly to thedetectors with kinematic distributions characterized by a temperature Th

Collisions without creation of QGP mdash In this case the collision starts by a pre-equilibrium partonic phase which directly leads to the hadronic phase without passingthrough any significant hydrodynamic or thermodynamic evolution After the elasticinteractions between the hadrons stop the species and their kinematics are fixed

124 Experimental Observables of the QGPA variety of observables exists giving insight into the properties of the QGP each ob-servable providing a complementary piece of information

Bulk physics light-flavor radiation

Figure 18 Hadron yields from ALICE at theLHC and fit with the statistical hadronizationmodel [15]

The bulk radiation is mainly composed oflight-flavored hadrons (u d s quarks) Hav-ing a typical scale of 1 fm 1(200 MeV)these hadrons cannot exist inside the decon-fined medium For this reason the light-flavor radiation measured by the detector isformed at the transition between the QGPand the physical vacuum taking place at thecritical temperature Tc 160minus 180 MeVThis fact is confirmed by the good agreementbetween the measured relative abundancesof the main light hadron species (includinglight hypernuclei) and the prediction of a sta-tistical hadronization model with fixed ther-modynamical parameters at the transitionphase see figure 18

The global hydrodynamical flow drivingthe expansion of the deconfined medium in-

duces the radial flow characterizing the light-flavor radiation pT spectrum Experimen-tally it is possible to observe this radial flow by measuring the pT dependence of the yieldfor the various species of the bulk radiation an example is given in figure 19

Moreover if the initial conditions are not spherically symmetric as it is in fact the casein non-central heavy-ion collisions the difference in pressure in different spatial directionswill lead to a further ldquodirectedrdquo or ldquoellipticrdquo flow (characterized by the v2 parametersin the Fourier expansion of the azimuthal particle distribution) Since the elliptic flowdepends on the initial conditions of the expending medium (like the geometry and theshear viscosity) the flow studies of hadron spectra can provide information about theearlier pre-hadronic stages of the collisions For example figure 110 illustrates how the

12 Heavy-Ion Physics Experimental Program 17

Figure 19 Transverse momentum distributionsof the sum of positive and negative particles asmeasured by ALICE fitted individually with ablast wave function compared to RHIC dataand hydrodynamic models [16]

Figure 110 Elliptic flow coefficient of chargedparticle in PbndashPb collisions as a function of cen-trality compared to viscous hydrodynamic re-sults [1718]

shear viscosity (ηs) of the medium can be estimated by the analysis of the centralitydependence of the v2 parameter

Strangeness productionWithin the light-flavor radiation strangeness production plays a peculiar role since thereare no strange valence quarks in the initial state of the collision as opposed to u and dquarks yet they are sufficiently light to be abundantly created in the course of the colli-sions High-pT strangeness production happens either at the early stages of high-energycollisions in hard partonic scattering processes by flavor creation and flavor excitation(see Feynman diagrams in figure 111) or during the subsequent partonic evolution viagluon splittings Low-pT strangeness production is dominated by non-perturbative pro-cesses like string fragmentation however due to the heavier mass of the strange quark(95plusmn 5 MeVc2) than the u and d quarks the production of strange hadrons in fragmen-tation processes is suppressed in comparison to the production of hadrons containing onlyu and d quarks

q

q s

s g

g s

s

g

g s

s g

g s

s

Figure 111 Feynman diagrams in pQCD at first order for the strangeness production inside QGP

18 Chapter 1 Physics Motivations

Figure 112 pT-integrated yield ratios of strange and multi-strange hadrons to (π+ + πminus) as afunction of 〈dNchdη〉 measured in the rapidity interval |y| lt 05 [20]

An enhancement of strange hadron production was historically proposed [19] as anindication of the QGP formation the argument is that strangeness production would beenhanced by the large energy density available in the medium the enhancement scal-ing with the strangeness content of each hadron Figure 112 shows the ratio of strangehadrons over pions as a function of event multiplicity for pp p-Pb and Pb-Pb collisionsIn this figure one can appreciate the difference of the measured enhancement for strangehadrons containing different numbers of strange quarks Ks mesons and Λ baryons con-taining one strange quark Ξ baryons containing two strange quarks and Ω baryonscontaining three strange quarks

JetsIn high-energy collisions a significant production of hard partons is observed thehadronization of these partons produces a narrow cone of hadrons and other particlescorrelated together named jet In heavy-ion collisions jet measurements offer the pos-sibility to probe the deconfined medium by measuring the energy loss of the initial hardparton (jet quenching) and the modification of the jet cone structure and composition(jet broadening) Due to the high energy involved in the production of hard partons jetphysics in heavy-ion collision basically started at RHIC in 2000rsquo whereradicsNN values of theorder of 100 GeV became available for the first time Today jet physics in heavy-ion col-lisions profits from the larger energies available at the LHC implying larger cross-sectionsfor hard scattered partons and an extended range of jet energies

In figure 113 and 114 two examples of jet physics results in heavy-ion collisions are

12 Heavy-Ion Physics Experimental Program 19

Figure 113 The b-tagged jet RAA as a functionof Npart for two jet pT selections in Pb-Pb atradicsNN = 276 TeV in CMS [21]

(GeVc)Tassoc

p1 15 2 25 3 35 4 45

)shyπ

++

π)

(p

(p+

0

02

04

06

08

1

12

1415)plusmn lt η∆06 lt plusmn lt 052 φ∆Bulk Ratio (shy052 lt

lt 04)η∆ lt 052 shy04 lt φ∆Peak shy Bulk Ratio (shy052 lt

Pythia (Peak shy Bulk Ratio)

= 276TeV 0shy10 centralNN

sPbshyPb

lt 100 GeVcTtrig

50 lt p

ALIminusPRELminus15474

Figure 114 Ratio of proton to pion spectraas function of pT for the ldquobulkrdquo and ldquopeak-bulkrdquo [22]

shown In figure 113 the nuclear modification factor (RAA) of b-tagged jets is shown as afunction of Npart as measured by the CMS experiment at the LHC in Pb-Pb collisions atradicsNN = 276 TeV A clear decreasing trend for RAA is observed for increasing values of

Npart interpreted as a manifestation of the jet-quenching mechanism In figure 114 theproton-over-pion ratios in the bulk and in jet are shown as a function of pT measuredby ALICE in Pb-Pb collisions at radicsNN = 276 TeV The comparison of the measuredproton-over-pion ratio in jets (ldquopeak-bulkrdquo) with the prediction from PYTHIA suggeststhat no significant medium-induced modification of particle ratios is at play in jets

Heavy flavorsThe abundant production of c and b quarks at LHC offers a unique possibility to un-derstand the details of the energy loss thermalization and hadronization mechanismscharacterizing the interaction of heavy quarks with the medium

The energy loss can be studied through the measurement of the pT-dependence of thenuclear modification factor RAA for the various heavy flavor hadron species In figures 115and 116 the RAA averaged over the main non-strange D-meson species is compared withthe RAA of light-flavored mesons and (non-prompt) Jψ from B decays respectivelyprobing the suppression hierarchy RB

AA gt RDAA amp Rlight quarks

AA reflecting the different energyloss of light charm and beauty quarks Despite the large uncertainties the data suggesta similar energy loss for the charm and light quark a scenario also supported by sometheoretical models [23] The heavy quark hadronization mechanism in the medium can bestudied by comparing the production of various species of heavy flavor hadrons [2425]

QuarkoniaQuarkonia are resonance states of charm-anticharm (charmonia) or bottom-antibottom(bottomonia) pairs Quarkonium measurements provide information on the properties of

20 Chapter 1 Physics Motivations

Figure 115 Prompt D-meson RAA as a func-tion of pT compared to the pion and charged par-ticles RAA in the 0-10 centrality classes [26]

rangpart

Nlang0 50 100 150 200 250 300 350 400

AA

R

0

02

04

06

08

1

12

14

(empty) filled boxes (un)correlated syst uncertψ() 50shy100 for nonshyprompt J

|lt05y |clt16 GeVT

pD mesons (ALICE) 8lt

= 276 TeVNNsPbshyPb

rangpart

Nlang shifted by +10 in plusmnπ

(CMS)ψ Nonshyprompt J|lt12y |clt30 GeV

Tp 65lt EPJC 77 (2017) 252

50shy80

40shy5030shy40

20shy3010shy20

0shy10

|lt08y |clt16 GeVT

p (ALICE) 8ltplusmnπ

ALIminusPUBminus129313

Figure 116 Comparison of the average D-meson RAA in 8ltpT lt16 GeVc with chargedpions in the same pT range and Jψ from Bdecays in 65ltpT lt30 GeVc [27]

the medium in the early stages of heavy-ion collisions being sensitive to the in-mediumdissociation and recombination mechanisms for the various quarkonium states Quarko-nium dissociation was indeed proposed as a signature of the production of QGP in heavy-ion collisions due to a color-screening effect [28 29] in analogy to the Debye-screeningin electrostatics coupled to a dynamical interaction of the heavy-quark pair with thesurrounding partons [3031]

Figure 117 Dimuon mass spectrum in the Υregion in Pb-Pb collisions at radicsNN = 502 TeVwith CMS experiment [32]

rangpart

Nlang0 50 100 150 200 250 300 350 400

AA

R

0

02

04

06

08

1

12

14-micro+micro rarr ψInclusive J

c lt 8 GeVT

p lt 4 y = 502 TeV 25 lt NN

sPb minusALICE Pb

c lt 8 GeVT

p lt 4 y = 276 TeV 25 lt NN

sPb minusALICE Pb

c gt 0 GeVT

p| lt 22 y = 02 TeV 12 lt |NN

sAu minusPHENIX Au

ALI-DER-112313

Figure 118 The participant number depen-dence of RAA for inclusive Jψ in ALICE in Pb-Pb collisions at radicsNN = 502 and 276 TeVand in PHENIX at forward rapidity in Au-Au atradicsNN = 200 GeV

12 Heavy-Ion Physics Experimental Program 21

The dissociation mechanism resulting in the suppression of the less bound quarkoniumstates is best illustrated in figure 117 showing the dimuon mass spectrum in the Υ regionmeasured by the CMS experiment with the Pb-Pb data at radicsNN = 502 TeV comparedto the expected yield in pp One can observe that the suppression of the Υ(3S) state isstronger than the one of the Υ(2S) with respect to the Υ(1S) due to the different bindingenergy of the two resonance states (sequential melting of quarkonium)

For the charmonium states a statistical recombination mechanism is expected to com-pete with dissociation for sufficiently large values of the cc cross-section expected forinstance in Pb-Pb collisions at the LHC energies The interplay of the suppression andrecombination mechanisms has indeed been proposed to explain the ALICE data for thecentrality dependence of the Jψ RAA in Pb-Pb at radicsNN = 502 and 276 TeV shown infigure 118 together with the PHENIX results in Au-Au collisions at radicsNN = 200 GeVFor 〈Npart〉 gt 120 the ALICE Jψ RAA shows no significant centrality dependence and isalmost a factor of 3 larger than the PHENIX data for the most central points no sizablerecombination mechanism being at play at RHIC energy Further insight on the role ofstatistical recombination in charmonium production at the LHC could come from thecomparison of the Jψ elliptic flow measurements with the theoretical models

Electromagnetic probesElectromagnetic radiation (real photons and dileptons from virtual photons) is emittedfrom a variety of processes prompt photons from initial hard scatterings thermal photonsand medium-modified ρ dileptons from the QGP phase real and dileptons from radiativedecays after hadronization The fact that electromagnetic radiation is emitted during thewhole evolution of the collision represents at the same time an advantage (for instancethe possibility of probing the entire lifetime of the fireball) and a drawback (the variouscomponents being hard to disentangle) Another advantage of electromagnetic radiationis that whenever emitted it is not affected during its propagation by the strong inter-action dominating inside the deconfined medium providing a clean probe of hadronicinteractions

Figure 119 shows the pT spectrum of real photons in Pb-Pb collisions atradicsNN = 276 TeV measured by ALICE for three centrality classes In all centrality

classes no evidence for medium influence is observed at high pT At low pT (gt 2 GeVc)on the contrary an excess of real photons with respect to pQCD real photon productionis observed for mid- and central collisions with a temperature of Teff asymp 300 MeV ex-tracted in central collisions [33] This excess might be related indeed to the productionof thermal photons from the QGP phase

Figure 120 shows the excess in the dimuon mass spectrum with respect tothe expected hadronic sources measured by NA60 in semi-central In-In collisions atradicsNN = 173 GeV compared to various theoretical scenarios This excess is domi-

nated by the medium-modified ρ line shape at low mass (gt 1 GeVc2) and by a thermalcontribution at intermediate mass ( 1 GeVc2) and its study allows one to shed lighton the relevant properties of QGP equation of state [34 35]

22 Chapter 1 Physics Motivations

Figure 119 Direct photon spectra in PbndashPbcollisions atradicsNN = 276 TeV for three central-ity classes compared to model in pp collisions atthe same energy scaled by the number of binarynucleon collisions for each centrality class [33]

Figure 120 Dimuon invariant-mass in semi-central In-In collisions with NA60 [34]

125 Proton-Proton Collisions

Proton-proton collisions present various aspects of interest in the context of heavy-ionphysics namely as a reference for heavy-ion observations test for pQCD calculationsinput for phenomenological non-perturbative models and environment for collectivity insmall systems

As a reference for heavy-ion collisions pp measurements are needed in order hot andcold nuclear matter effects to be properly disentangled respectively in nucleus-nucleusand proton-nucleus collisions This implies two necessities collecting pp reference dataat the same radicsNN energy as more complex collision systems and finding appropriatevariables which could relate pp pA and AA observations A primary example is givenby the nuclear modification factor (RAA) defined as the direct ratio of production cross-sections in AA or pA over the corresponding pp reference scaled by the number of binarycollisions for example to study the charged-particle production [36]

Proton-proton collisions are also an ideal environment for the study of hard and softprocesses in vacuum In the first case (jets Jψ Υ ) one has the possibility to testpQCD calculations in the second case constraints on phenomenological models can bederived in terms of kinematic distributions and production cross-sections [3738]

Finally it is possible to use pp collisions for studying the emergence of collective ef-fects in small systems This study is typically performed analyzing the data in classes ofcharged particle multiplicity the onset of collectivity being driven by the event activityIn this context the observation of collective effects in large-activity pp and p-Pb colli-sions showing striking similarities with those observed in Pb-Pb collisions represents anintriguing challenge for theoretical models [39]

13 Low-Mass Dimuon Measurements in ALICE 23

13 Low-Mass Dimuon Measurements in ALICEThis thesis work is focused on low-mass dimuon measurements in pp collisions atradics = 13 TeV For this reason it is interesting to report here about low-mass dimuon re-

sults and currently ongoing analyses in the other collision systems and energies availableLow-mass dimuon production is studied in ALICE in Pb-Pb collisions atradicsNN = 276 and502 TeV in p-Pb collisions at radicsNN = 502 and 816 TeV as well as in pp collisions atradics = 276 502 7 and 8 TeV Due to the favorable position of its two-body decay in the

low-mass dimuon region with no significant competing sources beyond the smooth cor-related continuum from open heavy flavors the φ-meson has been the privileged subjectof the low-mass dimuon analyses in the first years of LHC operation

Pb-Pb collisionsThe LHC provided Pb-Pb collisions in Run 1 at radicsNN = 276 TeV and in Run 2 atradicsNN = 502 TeVDue to the limited statistics of the Run 1 data the φ-meson study is limited to the

pT range from 20 to 50 GeVc for the dimuons in Pb-Pb collisions at radicsNN = 276 TeVsee figure 121 where the lower limit is imposed by the hardware trigger condition onsingle muons (pT 1 GeVc) and the upper limit is defined by the available statisticsThe analysis of the Run 1 low-mass dimuon data allowed the measurement of the nu-clear modification factor RAA of the φ-meson at forward rapidity in Pb-Pb collisions atradicsNN = 276 TeV shown in figure 122 together with the corresponding ALICE mea-

surement at mid-rapidity and the PHENIX measurement at mid-rapidity in Au-Au andCu-Cu collisions at radicsNN = 200 GeV As can be seen from the comparison of the twoALICE sets of points the RAA does not exhibit any significant dependence on the rapidityregion considered on the contrary the PHENIX points seem systematically higher thanthe ALICE ones although still compatible with the latter within the total uncertaintiesAll the data sets agree on the general decreasing trend of RAA as a function of 〈Npart〉

The larger statistics available from the first Pb-Pb data taking at radicsNN = 502 TeVof Run 2 (2015 a second one being foreseen for 2018) allows the analysis of φ-mesonproduction to be performed up to 7 GeVc starting again from 2 GeVc due to thehardware trigger condition The pT dependence of the φ-meson yield could be studied inseveral centrality classes as shown in figure 123 where the data points are fitted withthe power-law function

dNdpTprop pT[

1 +(pTp0

)2]n (133)

where n and p0 are the free parameters of the fit The centrality dependence of φ-mesonproduction is also studied by looking at the central-to-peripheral ratio RAA as a functionof 〈Npart〉 as shown in figure 124 this dependence suggests a general decreasing trendof RAA as a function of centrality

p-Pb collisionsThe LHC provided in Run 1 p-Pb collisions at radicsNN = 502 TeV and in Run 2 at

24 Chapter 1 Physics Motivations

Figure 121 φ-meson yield as a function of pT inPb-Pb collisions at radicsNN = 276 TeV in threecentrality classes and two rapidity regions [40]

Figure 122 φ-meson RAA as functionof 〈Npart〉 in Pb-Pb collision at radicsNN =276 TeV and Au-Au and Cu-Cu collisions atradicsNN = 200 GeV [40]

)c (GeVT

p

0 1 2 3 4 5 6 7 8

shy1 )c

(G

eV

T

pd

yd

φN

2d

6minus10

5minus10

4minus10

3minus10

2minus10

1minus10

1

10

210

Centr 0shy10 x 8 Centr 10shy20 x 2

Centr 20shy40 Centr 40shy60

Centr 60shy90 Power law

= 502 TeVNN

sPbshyPb

lt 4y25 lt

ALICE Preliminary

ALIminusPRELminus117465

Figure 123 φ yield as a function of pT for fivecentrality classes in Pb-Pb collisions at radicsNN =502 TeV [41]

rang part

N lang

0 50 100 150 200 250 300 350

AA

R

0

05

1

15 = 502 TeV

NNsPbshyPb

shymicro+micro rarr φ

lt 4y25 lt c lt 7 GeV

Tp2 lt

ALICE Preliminary

ALIminusPRELminus131928

Figure 124 φ nuclear modification factor Rcpas a function of Npart in Pb-Pb collisions atradicsNN = 502 TeV [41]

13 Low-Mass Dimuon Measurements in ALICE 25

radicsNN = 816 TeV Because of the different energy of the proton and Pb beams in

p-Pb collisions the nucleon-nucleon center-of-mass moves in the laboratory with a posi-tive rapidity in the direction of the proton beam The directions of the proton and Pbbeam orbits can be inverted during the p-Pb data taking periods allowing the ALICEmuon spectrometer to access a forward rapidity region when the proton beam is directedtowards the muon spectrometer (203 lt y lt 353) and a backward rapidity region whenthe Pb beam is directed towards the muon spectrometer (minus446 lt y lt minus296)

y

shy4 shy2 0 2 4

(b

)y

dφ

σd

0

005

01

015

02data

HIJING

DPMJET

=502 TeVNN

sALICE pshyPb

c lt 7 GeVT

p1 lt

ALI-PUB-94059

Figure 125 φ-meson cross-section as a func-tion of y in p-Pb collisions at radicsNN = 502 TeVand 10 lt pT lt 70 GeVc Predictions fromHIJING and DPMJET are also shown for com-parison

)c (GeVT

p

0 1 2 3 4 5 6 7

)shymicro

+micro

rarr φ

(F

BR

0

05

1

15

data

HIJING

DPMJET

=502 TeVNN

sALICE pshyPb

|lt353y296lt|

ALI-PUB-94063

Figure 126 φ-meson forward-backward cross-section ratio as a function of pT for 296 lt |y| lt353 in p-Pb collisions at radicsNN = 502 TeVPredictions from HIJING and DPMJET are alsoshown for comparison

Figure 125 reports the φ-meson cross-section as a function of y for p-Pb collisions atradicsNN = 502 TeV showing a clear asymmetry between the forward and backward regions

not reproduced by the predictions of HIJING and DPMJET also shown To establish a moredirect comparison of the φ-meson cross-section in the forward and backward regions thecross-section was extracted as a function of pT in the common |y| range 296 lt |y| lt 353in terms of the ratio RFB between the forward and backward cross-section shown infigure 126 The observation of RFB values significantly different than 1 is consistent withthe observation of the asymmetry in the y dependence of the cross-section reported infigure 125 No significant pT dependence of RFB is visible within statistical and systematicuncertainties

p-Pb data have also been taken in 2016 at radicsNN = 816 TeV with a total integratedluminosity larger than the one of the radicsNN = 502 TeV data taking (see table 22) Theanalysis of this data is currently ongoing and is expected to produce the first preliminaryresults in 2018

pp collisionsLow-mass dimuon data in pp collisions are available at several center-of-mass energiesradics = 276 7 and 8 TeV (data taken during the LHC Run 1) 502 and 13 TeV (data

taken during the LHC Run 2)

26 Chapter 1 Physics Motivations

pp results atradics = 276 TeV [13] are used as a reference for Pb-Pb collisions at

the same radicsNN Figure 127 shows the opposite-sign dimuon signal (after combinatorialbackground subtraction) integrated over the available pT and y ranges compared to theresult of the hadronic cocktail fit the good quality of the data-MC comparison leads toa robust extraction of the φ-meson signal Figure 128 shows the φ-meson differentialcross-section as a function of pT compared to the Levy-Tsallis function [42]

1pT

dNdpTprop1 +

radicpT2 +m2

φ minusmφ

nT

minusn (134)

with n and T as free parameters In figure 128 data are also compared to the predictionsby PHOJET and PYTHIA tunes ATLAS-CSC D6T Perugia0 and Perugia11 As one cansee a good agreement is found between predictions and data except for PYTHIA tunesPerugia0 and Perugia11 which underestimate the cross-section measurement

)2c (GeVmicromicroM

0 02 04 06 08 1 12 14

)2

c (

dim

uo

ns p

er

25

Me

V

micromicro

Md

Nd

0

05

1

15

310times

micromicro

rarrρ

0πmicromicrorarrω

micromicro

rarr φ

γmicromicrorarrrsquoηmicromicro rarr bb

γmicro

micro rarr

η

micromicro

rarr ω

micromicro rarr cc

= 276 TeVspp

lt 4y25 lt

c lt 5 GeV T

p1 lt

micromicro

rarr η

ALICE

ALI-PUB-94035

Figure 127 Dimuon opposite-sign mass spec-trum in pp collisions at

radics = 276 TeV af-

ter combinatorial background subtraction pT-and y-integrated data compared to the hadroniccocktail fit [13]

)c (GeVT

p

0 1 2 3 4 5

))c

(m

b(

Ge

V

Tp

dy

dφ

σ2

d

shy310

shy210

shy110

1 = 276 TeVsALICE pp

lt 4y25 lt

Data

PYTHIA ATLASshyCSC

PYTHIA D6T

PYTHIA Perugia0

PYTHIA Perugia11

PHOJET

LevyshyTsallis

ALI-PUB-94047

Figure 128 φ-meson cross-section as a func-tion of pT in pp collisions at

radics = 276 TeV

Predictions from PHOJET and PYTHIA are alsoshown for comparison as well as the result of afit with a Levy-Tsallis function [13]

Low-mass dimuon data taken in 2015 in pp collisions atradics = 502 TeV offer the

possibility to establish a data-based reference for Pb-Pb and p-Pb data at the sameenergy The opposite-sign dimuon signal in pp collisions at

radics = 502 TeV is shown

in figure 129 integrated over the available pT and y ranges compared to the resultof the hadronic cocktail fit the good quality of the data-MC comparison allows for arobust extraction of the φ-meson signal The pT-differential φ-meson cross-section couldbe extracted up to 6 GeVc as shown in figure 130 compared to different theoreticalmodels

Low-mass dimuon data in pp collisions atradics = 7 TeV allowed for the study of the pT-

differential ω and φ cross-sections The hadronic cocktail fit on the isolated opposite-signdimuon signal is shown in figure 131 The identification of the ω and the φ meson signals

13 Low-Mass Dimuon Measurements in ALICE 27

)2c (GeVmicromicroM

0 02 04 06 08 1 12 14

)2

c (

dim

uo

ns p

er

25

Me

V

micromicro

Md

Nd

1000

2000

3000

4000 = 502 TeVspp

lt 4 y25 lt c lt 7 GeV

Tp1 lt

γmicro

microrarr

η

micromicrorarrρ

micromicro

rarrω

0πmicromicrorarrωmicro

microrarr

φ

γmicromicrorarrrsquoη

cc

bb

γmicro

microrarr

η

micromicrorarrρ

micromicro

rarrω

0πmicromicrorarrωmicro

microrarr

φ

γmicromicrorarrrsquoη

cc

bb

ALICE Preliminary

ALIminusPRELminus131989

Figure 129 Dimuon opposite-sign mass spec-trum in pp collisions at

radics = 502 TeV af-

ter combinatorial background subtraction pT-and y-integrated data compared to the hadroniccocktail fit [41]

)c (GeVT

p

0 1 2 3 4 5 6 7 8

))c

(m

b(

Ge

V

Tp

dy

dφ

σ2

d

3minus10

2minus10

1minus10

1 = 502 TeVspp

ATLASshyCSCD6TPerugiashy0

Perugiashy11PhojetMonashshy2013

ALICE Preliminary

lt 4y25 lt

ALIminusPRELminus132725

Figure 130 φ-meson cross-section as a functionof pT in pp collisions at

radics = 502 TeV [41]

resulted in the measurements of the pT differential cross-section shown in figure 132 for theω-meson only calculation based of PHOJET and PYTHIA with ATLAS-CSC and D6T tunesfairly agree with the data while the Perugia0 and Perugia11 PYTHIA tunes underestimatethe cross-section by about a factor of 2 and 25 respectively (the same conclusions standfor φ-meson)

)2M (GeVc

0 02 04 06 08 1 12 14

)2

dN

dM

(p

air

s p

er

25 M

eV

c

0

1000

2000

3000

4000

cc

micro micro

rarr φ

micro micro

rarr ω

micro micro rarr ρ

γ micro

micro rarr

η

micro micro

rarr η

0π micro micro rarr ω

γ micro micro rarrrsquo η

lt 5 GeVct

1 lt p

= 7 TeVsALICE pp

25 lt y lt 4

ALIminusPUBminus26621

Figure 131 Dimuon opposite-sign mass spec-trum for pp collisions at

radics = 7 TeV after com-

binatorial background subtraction pT- and y-integrated sample compared to the result of thehadronic cocktail fit [43]

Figure 132 ω-meson cross-section as a func-tion of pT in pp collisions at

radics = 7 TeV com-

pared to the predictions of various phenomeno-logical models [43]

Finally low-mass dimuon data are also available in pp collisions atradics = 8 TeV This

28 Chapter 1 Physics Motivations

)2c (GeVmicromicroM

0 02 04 06 08 1 12 14

)2

c (

dim

uo

ns p

er

25

Me

V

micromicro

Md

Nd

0

2000

4000

6000

8000

10000

12000 ALICE Preliminary

s = 8 TeVradicpp

25 lt y lt 4

c lt 80 GevT

p15 lt

γmicromicro

rarr

η

γmicromicro rarrrsquo η0πmicromicro rarr ω

bb

micromicro

rarr ω micro

micro rarr φ

micromicro rarr ρcc

ALIminusPRELminus133143

Figure 133 Dimuon opposite-sign mass spec-trum in pp collisions at

radics = 8 TeV after com-

binatorial background subtraction pT- and y-integrated data compared to the hadronic cock-tail fit [41]

)c (GeVT

p

0 1 2 3 4 5 6 7 8

))c

(m

b(

Ge

V

Tp

dy

d φσ

2d

3minus10

2minus10

1minus10

1hEmpty

Entries 0

Mean x 0

Mean y 0

Std Dev x 0

Std Dev y 0

s = 8 TeVradicpp ATLASshyCSCD6TPerugiashy0Perugiashy11

PhojetMonashshy2013

ALICE Preliminary

lt 4 y25 lt

ALIminusPRELminus133207

Figure 134 φ-meson cross-section as a functionof pT in pp collisions at

radics = 8 TeV [41]

offers the possibility to enrich the study of light neutral meson production in pp collisionsas a function of

radics providing at a same time a useful reference for the p-Pb data at

the same radicsNN energy The available statistics larger than the one in pp collisions atradics = 7 TeV allows to extract the low-mass dimuon analysis up to pT = 80 GeVc On

the other side the higher single muon threshold implies that the analysis could only startfrom pT = 15 GeVc The pT- and y-integrated opposite-sign dimuon signal is shown infigure 133 with the associated hadronic cocktail fit Figure 134 shows the extracted φcross-section as a function of pT compared to three predictions of EPOS-LHC and PYTHIA-8with and without multiple parton interactions As one can see the EPOS-LHC predictionoverestimates the φ cross-section while the comparison to the PYTHIA-8 predictions seemsto favor a scenario including multiple parton interactions

Chapter 2

ALICE at the CERN LHC

Summary21 The Large Hadron Collider 29

211 The CERN accelerator complex 29212 The LHC schedule 30213 The Experimental Heavy-Ion Program 32

22 A Large Ion Collider Experiment (ALICE) 33

221 The Central Barrel 34222 The Forward Detectors 36223 The Muon Spectrometer 38224 The ALICE software framework 40225 The ALICE Upgrade 41

21 The Large Hadron ColliderThe Large Hadron Collider (LHC) straddling the FrenchSwiss border in average100 meter underground in a circular tunnel of some 27 km of circumference is as fornow the worldrsquos largest and most powerful particle collider It operates at the TeVenergy scale with nominal energy of 14 TeV (in pp collision) and 55 TeVnucleon pair(in Lead-Lead) foreseen to be achieved in 2018 To carry out this technical challengethe CERN machine engineers developed a new accelerating technique based on supercon-ducting magnets (NbTi) cooled down to a temperature below 2 K which can generatemagnetic fields up to 8 T Four main experiments have been installed within the LHCring namely ATLAS (A Toroidal LHC ApparatuS) CMS (Compact Muon Solenoid)LHCb (LHC-beauty) and ALICE (A Large Ion Collider Experiment) ALICE will bedescribed in more details in section 22

211 The CERN accelerator complexFigure 21 displays the LHC ring and the full complex of accelerators upstream the LHCFollowing a complete trip from the proton source to the final output within the LHCprotons are produced in the LINAC 2 and then injected in the BOOSTER (PSB forProton Synchroton Booster) first accelerator ring This accelerating stage increases the

30 Chapter 2 ALICE at the CERN LHC

Figure 21 The LHC and the CERN accelerator complex [44]

proton energy from 50 MeV to 14 GeV Once protons have reached the top PSB energythey are injected into the Proton Synchroton (PS) where their energy is ramped up to25 GeV and then into the Super Proton Synchrotron (SPS) (7 km in circumference) tothe nominal energy of 450 GeV The latter is the LHC injector and is used in parallel toprovide particle beam to other CERN experiments (for example NA61SHINE)

In the case of the LHC heavy ions runs the lead ions are firstly accelerated in aLINAC 3 then further accelerated in the Low Energy Ion Ring (LEIR) which increasesthe lead energy from 42 MeV to 72 MeVnucleon before injection in the PS The leadions are then accelerated and injected in the SPS and from there to the LHC

212 The LHC schedule

During the first LHC run (Run 1 2009ndash2013) several energies and three collision systems(pp p-Pb Pb-Pb) have been explored In pp collisions five different center-of-massenergies have been considered 09 236 276 7 and 8 TeV p-Pb and Pb-Pb collisionshave been measured at radicsNN = 502 TeV and radicsNN = 276 TeV respectively Run 1was followed by a first Long Shutdown (LS1) mainly dedicated to the upgrade of theaccelerator system mdash resulting in an increase of the collision energy from 7minus 8 TeV to13minus 14 TeV in proton-proton collisions (from 276 TeV to 502 TeV in Pb-Pb collisions)mdash and the completion of the detectors of some of LHC experiment (in the case of ALICEthe electromagnetic calorimeter and the Transition Radiation Detector were updated)Run 2 started in mid-2016 and is planned to last until the end of 2018 with pp collisionsdelivered at 502 and 13 TeV Pb-Pb collisions delivered at radicsNN = 502 TeV and p-Pbcollision delivered at radicsNN = 502 minus 8 TeV LS2 is foreseen to start at the beginningof 2019 ending in late 2020 during LS2 the installation phase of the ALICE upgrade

21 The Large Hadron Collider 31

program will take place During Run 3 pp and Pb-Pb collisions will be delivered atthe nominal LHC energy (14 TeV for pp and radicsNN = 55 TeV for Pb-Pb) and the firstPb-Pb data taking at high-luminosity will take place LS3 will be mainly devoted to theinstallation of the High-Luminosity LHC (HL-LHC) providing unprecedented luminositiesin pp collisions at the designed LHC energy During LS3 the CMS and ATLAS upgradeprograms will be finalize Run 4 will see the beginning of the HL-LHC program in ppcollisions and the continuation of the high-luminosity heavy ion program

Figure 22 LHC schedule for 2015 to 2035 [45]

a Delivered Luminosity Measurement in ALICE

In high energy physics the luminosity is an essential concept expressing the interactionrate normalized to the intensity of the interacting fluxes of particles In the specific caseof a collider with beam pulsing the luminosity is defined by equation (21) where Nb

is the number of particles per bunch nb is the number of bunches per beam frev therevolution frequency γ is the relativistic gamma factor εn the normalized transversebeam emittance βlowast the beam beta function at the interaction point (for more details seechapter 4 of [46]) and F the geometric luminosity reduction factor due to the crossingangle at the interaction point (IP) [47]

L = N2b nbfrevγ

4πεnβlowastF (21)

The luminosity determination in ALICE is based on visible cross section measurementsperformed during van der Meer (vdM) scans [48 49] In standard vdM scans the twobeams are moved across each other in transverse directions x and y The two scans are

32 Chapter 2 ALICE at the CERN LHC

performed separately and the visible cross section is given by the detectors used for thedefinition of the minimum bias triggering conditions typically the V0 and T0 in ALICE

213 The Experimental Heavy-Ion ProgramThe goal of the LHC heavy-ion program is to produce the hottest the largest and thelongest-lived volumes of QGP in laboratory and to provide a precise characterizationof this new state of matter For that nucleus-nucleus collisions (A-A) are delivered atenergies up to radicsNN = 55 TeV Proton-proton and proton-nucleus collisions are also partof the LHC heavy-ion program providing the needed baseline (in terms of vacuum-likecross-sections and cold nuclear matter effects) allowing for a correct interpretation of theobservations in A-A collisions

In addition to the LHC there are other experimental complexes developing specificheavy-ion programs The most important one is the experimental program implementedat the Relativistic Heavy Ion Collider (RHIC) [50] hosted at the Brookhaven NationalLaboratory (BNL) in Long Island (New York US) RHIC is a dedicated heavy-ion facilityand it has a large flexibility in the choice of both the nuclear species accelerated (fromprotons to Uranium) and the center-of-mass energy (in the range radicsNN = 75minus200 GeV)Four detectors are installed at RHIC one of them STAR still operates today whilePHOBOS BRAHMS and PHENIX completed there operations respectively in 2005 2006and 2016 At CERN a fixed-target heavy-ion program complementary to the LHC one isalso running at the SPS with the NA61SHINE experiment [51] currently performing asystematic scan both in beam energy (radicsNN = 45minus 173 GeV) and colliding system size

In addition to the upgrade of some of the existing experiments several new heavy-ionprograms are under discussion or already in preparation [52]

bull The NICA1 facility at JINR [53] will operate in collider mode in the center-of-massenergy range radicsNN = 4 minus 11 GeV and in fixed-target mode in the center-of-massenergy range radicsNN = 19minus 24 GeV

bull The FAIR2 [54] facility at GSI3 will provide fixed-target collisions in the center-of-mass energy range radicsNN = 2minus 29 GeV

bull The AFTER4 project [55] aiming at running a fixed-target heavy-ion program withthe LHC beams at a center-of-mass energy of radicsNN asymp 72 GeV

bull The NA60+ [5657] is a project of fixed-target experiment based at the SPS focusingon dimuon observables at a center-of-mass energy range radicsNN = 63 ndash 173 GeV

1Nuclotron-based Ion Collider fAcility2Facility for Antiproton and Ion Research3Gesellschaft fuumlr Schwerionenforschung mbH4A Fixed Target ExpeRiment at LHC

22 A Large Ion Collider Experiment (ALICE) 33

22 A Large Ion Collider Experiment (ALICE)

Figure 23 Scheme of the ALICE detector

ALICE is an experiment optimized for the study of the physics of strongly interactingmatter at extremely high energy density focusing in particular on the investigation of theQGP state and the characterization of its properties A key design consideration drivingthe developement of the ALICE detector is the possibility to study the most energeticPb-Pb collisions delivered by the LHC This is done by measuring the particles emergingfrom the interaction region it is achieved by ALICE by exploiting a rich variety of sub-detectors see figure 23 based on different technologies described in the following sections[58] Beyond the heavy-ion program ALICE is also interested in collecting data in proton-proton (pp) and proton-Lead (p-Pb) collisions where no large volumes of deconfinedmatter are supposed to be produced to be used as a reference for the Pb-Pb ones

In table 21 and table 22 the ALICE running conditions in the LHC Run 1 and Run 2respectively are summarized

System ECM [TeV] Year Delivered luminosity

pp

09 2009 196 microbminus1

236 2009 087 microbminus1

276 2011 46 nbminus1

2013 129 nbminus1

7 2010 05 pbminus1

2011 49 pbminus1

8 2012 97 pbminus1

p-Pb 502 2012 15 microbminus1

2013 0891 nbminus1 and 140 nbminus1

Pb-Pb 276 2010 9 microbminus1

2011 146 microbminus1

Table 21 Summary of Run 1 ALICE data taking considered for published or ongoing analyses [59]

34 Chapter 2 ALICE at the CERN LHC

System ECM [TeV] Year Delivered luminosity

pp

502 2015 14951 nbminus1

132015 694 pbminus1

2016 1335 pbminus1

2017 192 pbminus1

p-Pb 502 2016816 2016 868 nbminus1 and 124 nbminus1

Pb-Pb 502 2015 280 microbminus1

Table 22 Summary of Run 2 ALICE data taking considered for published or ongoing analyses [59]

221 The Central Barrel

The ALICE central barrel refers to the assembly of detectors installed around the inter-action point inside the L3 magnet These detectors are dedicated to the tracking andidentification of isolated charged particles and photons as well as to the reconstructionof jets

Inner Tracking System (ITS)

The Inner Tracking System (ITS) is the internal tracker of ALICE It is formed by sixcylindrical layers of silicon detector the innermost one having an internal radius of 39 cmlimited by the external radius of the beam pipe The radius of the outermost layer is430 cm The geometric parameters of the ITS are summarized in table 23

sub-system name layer technology r(cm) plusmnz(cm)

SPD 1 Pixel 39 1412 Pixel 76 141

SDD 3 Drift 150 2224 Drift 239 297

SSD 5 Strip 380 4316 Strip 430 489

Table 23 ITS Geometric features

The pseudo-rapidity coverage of the ITS is |η| lt 09 The six layers are grouped intosix groups of two layers each differing by the adopted technology The two innermost lay-ers are composed of silicon pixel detectors (SPD) the central one of silicon drift detectors(SDD) the two outermost are composed of silicon strip detectors (SSD) The ITS allowsthe position of the primary and secondary (from strange and charmed particles) verticesto be determined with a resolution better than 200 microm in rφ and 300 microm in z directionFurthermore it contributes to the particle identification complementing the informationprovided by the TPC especially for the low momentum particles (p lt 200 MeVc)

22 A Large Ion Collider Experiment (ALICE) 35

Time Projection Chamber (TPC)

The Time Projection Chamber (TPC) is the main detector of the central barrel It iscomposed of a 51 m long cylindrical drift volume of 90 m3 developing between an innerradius of 85 cm and an outer radius of 247 cm This volume is filled with NendashCO2 and isdivided into two parts by the central cathode which is kept at minus100 kV The end platesare equipped with multiwire proportional chambers (MWPC) As the ITS the pseudorapidity coverage is |η| lt 09 In addition to tracking the TPC provides charged-particleidentification via measurement of the specific ionization energy loss dEdx Due to theadopted technology and the large size the TPC is the slowest detector of ALICE thuslimiting the interaction rate that can be supported

Transition Radiation Detector (TRD)

The Transition Radiation Detector (TRD) is composed of eighteen super-modules dividedinto thirty modules arranged in six radial layers and five sectors along the beam directionThe TRD has full azimuth coverage and spans the pseudo-rapidity region |η| lt 09This sub-detector provides particle identification for electrons of momentum larger than1 GeVc

Time-Of-Flight (TOF)

The Time Of Flight (TOF) detector allows the particle time-of-flight to be measuredThe TOF coverage is |η| lt 09 in full azimuth It has a modular structure organized intoeighteen sectors in azimuth and five modules along the beam axis The whole detectoris inscribed in a cylindrical volume with an internal radius of 370 cm and an externalone of 399 cm The TOF has an intrinsic time resolution of about 50 ps thanks to thetechnology of Multi-Resistive Plate Chambers (MRPC)

High-Momentum Particle Identification Detector (HMPID)

The ALICE HMPID is based on proximity focusing Ring Imaging Cherenkov (RICH)counters and consists of seven modules mounted in an independent support cradle fixedto the space frame at the radial distance of 490 cm from the interaction point Thepseudo-rapidity acceptance is |η| lt 06 and an azimuthal coverage develops between 1and 59 corresponding to 5 of the central barrel acceptance The HMPID allows oneto extend the particle identification for π and K up to pT asymp 3 GeVc and pT asymp 5 GeVcfor protons

PHOton Spectrometer (PHOS)

The PHOton Spectrometer (PHOS) is a high resolution electromagnetic spectrometercovering the pseudo-rapidity range |η| lt 013 and the azimuth between 220 to 320 andinstalled at the radial distance of 460 cm The detector technology is based on lead-tungstate (PbWO4) crystals The PHOS is used to detect photons in the transversemomentum range between 05 to 10 GeVc including diphotons coming from the decayof the light pseudoscalar neutral mesons

36 Chapter 2 ALICE at the CERN LHC

ElectroMagnetic Calorimeter (EmCal)

The ElectroMagnetic Calorimeter (EMCal) and its extension the Di-jet Calorimeter(DCal) are sampling electromagnetic calorimeters with the pseudo-rapidity coverage|η| lt 07 and azimuth coverage from 80 to 187 (for the EMCal) and 260 to 327 (for theDCal) Specific allowance is made in the DCal acceptance for the space occupied by thePHOS detector The combined information of the EmCal and the DCal allows to studyjets and di-jets providing trigger signals for hard jets photons and electrons

222 The Forward DetectorsIn this section the ALICE sub-detectors covering the forwardbackward acceptance regionare presented These detectors are used to measure global observables especially thecentralityactivity of the collisions and the event plane

Forward Multiplicity Detector (FMD)

The Forward Multiplicity Detector (FMD) is based on the silicon strip technology Itis divided in seven disks perpendicular to the beam pipe located at distances between42 and 225 cm from the interaction point The goal of this sub-detector is to study thecharged particle multiplicity in the pseudo-rapidity ranges minus34 lt η lt minus17 and17 lt η lt 51 complementary to the one of the ITS

T0

The T0 is composed of two arrays of Cherenkov counters circularly arranged around thebeam pipe with a time resolution better than 50 ps The forward and backward parts ofthis sub-detector are located at 375 cm and minus727 cm covering a pseudo-rapidity rangeof 461 lt η lt 492 and minus328 lt η lt minus297 respectively It participates to thetrigger decision and to the estimation of the luminosity

V0

The V0 is composed of two scintillator disks installed around the beam axis on each sideof the interaction point The V0-A (for A-side corresponding to positive values of z) isinstalled at 329 cm from the interaction point it has a diameter of 100 cm and covers thepseudo-rapidity range 28 lt η lt 51 The V0-C (for C-side corresponding to negativevalues of z) is installed at minus90 cm from the interaction point it has a diameter of 74 cmand covers the pseudo-rapidity range minus37 lt η lt minus17

The V0 measures the charged particle multiplicity and by the measurement of thetime-of-flight difference between the A and C scintillators makes possible to identify andreject the beam-gas5 events This technique is illustrated in figure 24 beam-beam andbeam-gas events can be easily discriminated on the basis of the time correlation of thetwo signals reported on the x and y axes

5 A beam-gas event corresponds to an interaction between a beam ion and a nucleus of the residualgas in the beam pipe vacuum

22 A Large Ion Collider Experiment (ALICE) 37

Figure 24 Weighted average time-of-flight of the particles detected in V0-C versus V0-A Thedashed line intersection represents the time of the collisions at the interaction point or the crossingtime of the background tracks at the vertical plane z = 0 [60]

The V0 participates in the minimum-bias trigger decision and in the estimation of theluminosity Furthermore this sub-detector is involved in the centrality measurement inPb-Pb collisions

Photon Multiplicity Detector (PMD)

The Photon Multiplicity Detector (PMD) consists of two identical planes of detectorsmade of gas proportional counters with honeycomb structure and wire readout with Leadconverter in between located at 360 cm from the interaction point in opposite side ofmuon spectrometer The PMD covers the pseudo-rapidity region (23 lt η lt 37) Itmeasures the multiplicity and spatial distribution of photons and estimates the transverseelectromagnetic energy and the reaction plane event-by-event

ALICE Diffractive Detector (AD)

The ALICE Diffractive detector (AD) is a ALICE sub-detector which was installed dur-ing the Long Shutdown 2 (2013-2014) The goal of this sub-detector is to increase thepseudo-rapidity coverage (from 88 to 132 units) and to enhance trigger efficiency forlight particles produced in diffractive events This sub-detector also participates in theestimation of the multiplicity event-by-event It is composed of two double layers of scin-tillator counters one on each side of ALICE sensitive to charged particles with pT downto 20 MeVc In the A-side AD is installed at z = 170 m and covers the pseudo-rapidityrange 49 lt η lt 63 In the C-side the sub-detector is installed at z = minus195 m andcovers the pseudo-rapidity range minus70 lt η lt minus48

38 Chapter 2 ALICE at the CERN LHC

Zero Degree Calorimeter (ZDC)

The Zero Degree Calorimeter (ZDC) is composed of two identical sets of quartz spaghetticalorimeters located on both sides of the ALICE detector in fully horizontal position1125 m from the interaction point Each set of detectors consists of a neutron anda proton calorimeter Each of the neutron calorimeters has dimensions 7x7x100 cm3

while the proton calorimeters have dimensions 228x12x150 cm3 The ZDC detector iscompleted by two small electromagnetic calorimeter (ZEM) placed at 735 m from theinteraction point on one side detecting the energy of particles emitted in the pseudo-rapidity range 48 lt η lt 57 The ZDC is used to estimate the centrality in Lead-Leadcollisions

223 The Muon Spectrometer

Figure 25 The ALICE muon spectrometer layout [61]

The ALICE muon spectrometer (represented in figure 25) is 17 m long Thepseudo-rapidity coverage is minus40 lt η lt minus25 corresponding to the angular range171 lt θ lt 178 The muon spectrometer was designed to study quarkonia (Jψand Υ families) and light vector meson production (η ρω and φ) through their dimuondecays and open charm and beauty production (B and D hadrons) in the single-muonchannel The spectrometer is composed of several elements described in the followingsections

a Front Absorber

The first element of the ALICE muon spectrometer starting from the interaction pointis the front absorber (or hadron absorber) The hadron absorber suppresses all particlesexcept muons coming from the interaction vertex (mainly πplusmn and Kplusmn) It is made of

22 A Large Ion Collider Experiment (ALICE) 39

carbon and concrete (cf figure 26) in order to limit the multiple scattering and theenergy loss of the muons The inner beam shield protects the tracking chambers frombackground originating from particles at small angles It is made of tungsten lead andstainless steel to minimize the background arising from primary particles emitted in thecollision and from their showers produced in the beam pipe and in the shield itself

Figure 26 The ALICE front absorber structure [62]

The absorber is located 90 cm away from the interaction point just after the V0-Cand is 413 cm long

b Dipole Magnet

The dipole magnet provides a maximum magnetic field of 07 T and an integral fieldof 3 T middot m It is a warm magnet (one of the largest warm dipoles in the world) andit is cooled with a demineralized water-cooling system ensuring operating temperaturesbetween 15 to 25 C Its dimensions are 5 m in length 71 m in width and 9 m in heightThe dipole is centered at 994 m from the interaction point and the free gap betweenpoles has a diameter of approximately 3 m The dipole is designed to provide a horizontalmagnetic field perpendicular to the beam axis and its polarity can be reverted Themagnetic field is defined by requirements on the mass resolution for the heavy Υ states

c Tracking Chambers

The tracking system of the muon spectrometer is composed of five stations each sta-tion made of two chambers The distance between two chambers of a same station isbetween 10 and 20 cm The chambers are based on a Multiwire Proportional Cham-ber (MWPC) technology with pad-segmented cathodes [63] The tracking system wasdesigned to achieve the spatial resolution of 100 microm in the bending plane needed for ob-taining an invariant mass resolution of sim 100 MeVc2 at the Υ mass The segmentationof the cathodes allows the spectrometer to operate with maximum hit densities of about5 middot 10minus2 cmminus2 sufficiently large to cope with the observed multiplicity in central Pb-Pbcollisions

40 Chapter 2 ALICE at the CERN LHC

d Iron Wall

The iron wall complements the hadron absorber It is 12 m thick and covers a transversesurface of 56times 56 m2 It is located 15 m away from the interaction point before thetrigger chambers The goal of this element is to suppress all hadrons emerging from thefront absorber The combined action of the iron wall and the front absorber imposesthe muons to have a minimum momentum of sim 4 GeVc in order to reach the triggerchambers

e Trigger Chambers

The ALICE muon spectrometer is equipped with two trigger stations allowing events ofinterest for the muon physics to be selected Each station is composed of two chambersbased on the Resistive Plate Chamber (RPC) technology ensuring the time resolution of2 ns necessary for the identification of the bunch crossing The first station is located at16 m just after the iron wall and the second station at 17 m

Several trigger conditions are hard-coded in the trigger electronics The electronicsprovides the possibility to use two pT thresholds used for different physics and the list oftriggers is

bull MSL at least one muon with pT larger than the low-pT threshold

bull MSH at least one muon with pT larger than the high-pT threshold

bull MLL at least two muons of same charge with pT larger than the low-pT threshold

bull MUL at least two muons of opposite charge with pT larger than the low-pT thresh-old

In addition to these trigger conditions the A-pT trigger condition can also be defined itis the minimum-pT trigger threshold for which a muon is firing the trigger and the valueof this trigger is 05 GeVc

In LHC Run 2 the single-muon high-pT threshold was set to 42 GeVc while thevalue of the single-muon low-pT threshold depended on the data taking periods In thepp data taking during Run 2 two different values have been considered for the single-muonlow-pT threshold 1 GeVc allowing one to access φ meson pT down to sim 15 GeVc and05 GeVc allowing one to access φ meson pT down to almost 0 GeVc

224 The ALICE software frameworkThe ALICE software (AliRoot [64] and AliPhysics [65]) is based on ROOT [66] a soft-ware originally designed at CERN for particle physics data analysis ROOT AliRoot andAliPhysics are written in C++ and are used to handle the online-offline data The soft-ware also manages the Monte-Carlo simulation framework by interfacing several MCgenerators (PYTHIA [67] HIJING [68]) and particle transport codes which simulate thedetector response (GEANT3 [69] GEANT4 [70] and FLUKA [71])

The working flow of the ALICE software is represented in figure 27 where the mainstructures of the online-offline handling are shown The reconstruction steps are the

22 A Large Ion Collider Experiment (ALICE) 41

same for the raw data and MC data At the end of the reconstruction chain the dataare available in the AOD format (Analysis Object Data) From the AOD data furtherdata formats can be derived designed for any specific analysis In the case of the analysisperformed in this thesis the AOD events are reduced to the AliLMREvent format containingthe information of interest for the study of light-neutral meson production decaying intomuons

Simulation Reconstruction

Mon

teCarlo

RealData

Particles

HitsSDigitsSDigits Digits

Clusters

Vertex

Tracks ESD AOD

Trigger

Detector

HLT

DAQ Raw Data

Online Offline

Figure 27 Schema of the reconstruction chain for data and simulation

225 The ALICE UpgradeDuring LHC Run 1 and Run 2 the goal of ALICE is to explore the unprecedented energyregime available in heavy ion collisions see section 124 In the LHC Run 3 and Run 4ALICE we move from the exploration phase to a precision-measurement phase For thisreason ALICE is undertaking a complex upgrade program of its detectors with theinstallation of the upgraded sub-detectors to take place in 2019ndash2020 during the LHCLong Shutdown 2

Physics Motivations

The ALICE upgrade will preserve the specificities of the ALICE physics program withrespect to the other LHC experiments The track reconstruction performance will beimproved in terms of spatial precision and efficiency in particular for low-momentumparticles in order to select more efficiently the decay vertices of heavy-flavor mesons andbaryons The particle identification capabilities of the apparatus will be consolidatedthey represent a crucial tool for the selection of heavy-flavor quarkonium and dileptonsignals at low momentum In the following the main items of the foreseen physics programare shortly reviewed

42 Chapter 2 ALICE at the CERN LHC

bull Heavy Flavors characterization of the parton energy loss study of the transportof heavy quarks in the medium and the hadronization of heavy flavors In ALICE thefocus is placed on the low-momentum region down to zero pT and the reconstructionof heavy-flavor hadrons (mesons and baryons) and the possibility to measure theflavor-dependence in low-momentum jets using light flavor strange and charmedhadrons reconstructed within jets

bull Quarkonia study of the quarkonia dissociation (and possible regeneration) asprobe of the deconfined nature and temperature of the medium In ALICE theemphasis is in the low-momenta region and the possibility to study Jψ ψ(2S) andΥ in central and forward rapidity At forward rapidity in particular the MuonForward Tracker (MFT) will allow the prompt Jψ component to be statisticallyseparated from the displaced production and the ψ(2S) to be observed even inthe most central PbndashPb collisions thanks to a strong reduction of the non-promptbackground

bull Low-Mass Dileptons and Thermal Photons estimation of the initial temper-ature of the medium and investigation of the chiral nature of the phase transitionALICE will access this physics both in the dielectron and dimuon channels down tozero pT

bull Beyond Standard Model specific studies are also undergoing to assess the sen-sitivity of ALICE to the measurement of possible low-mass dark matter bosonsdecaying into electron or muon pairs thanks to the improvement of the discrimina-tion between prompt and non-prompt dileptons

Inner Tracking System (ITS)

The current ALICE Inner Tracking System (ITS) will be totally dismounted at the endof the LHC Run 2 to be replaced by a new detector during Long Shutdown 2 The newITS [72] will be composed of seven cylindrical layers of Monolithic Active Pixel Sensors(MAPS) the innermost one having an internal radius of 224 mm limited by the externalradius of the future beam pipe The internal radius of the outermost layer is 3918 mm

The hit resolution of the detector will be of about 5 microm and the material budget ofthe three innermost layers will be reduced from the present 11 to 03 of the radiationlength per layer these features provide an improvement by a factor about three for thetrack impact parameter resolution in the transverse plane The new ITS would have apseudo-rapidity coverage of |η| lt 122 This upgrade will improve the precision in thesecondary vertex separation (from beauty charm and strange particle decays)

Muon Forward Tracker

The Muon Forward Tracker (MFT) [73] will be a new sub-detector of ALICE made of fivedisks of the same MAPS used in the upgraded ITS The MFT will provide precise track-ing and secondary vertex reconstruction for muon tracks in the pseudo-rapidity regionminus36 lt η lt minus25 within the acceptance of the muon spectrometer

22 A Large Ion Collider Experiment (ALICE) 43

Figure 28 Simulation of low-mass dimuons with and without ALICE upgrade

The measurement of prompt dimuon sources in the low-mass region will strongly ben-efit from the addition of the MFT to the muon spectrometer A significant improvementup to a factor of about 4 is expected for the mass resolution of the narrow resonancesη ω and φ for which resolutions of sim 15 MeVc2 are expected (to be compared withthe current sim 50 MeVc2 resolution at the mass of the φ meson see figure 28) thiswill translate into a significant improvement of the measurements involving these parti-cles allowing at the same time a reliable identification of the underlying thermal dimuoncontinuum and the measurement of the in-medium modified line shape of the short-livedρ meson A precision of about 20 is expected for the observation of these sourcescurrently not feasible due to the very small signal-over-background ratio affecting themeasurement with the present muon spectrometer

TPC

The expected increase of the LHC luminosity after LS2 corresponding to an interactionrate about 50 kHz in PbndashPb implies that TPC operation with a gating grid is no longerpossible This motivates the choice of GEMs for the new readout chambers since theyfeature intrinsic ion blocking capabilities that avoid massive charge accumulation in thedrift volume from back-drifting ions and prevent excessive space-charge distortions Thepresent particle identification (PID) capability via the measurement of the specific ioniza-tion dEdx and the combined momentum resolution of the central barrel tracking systemmust be retained by the TPC upgrade [74] preserving the excellent performance of thecurrent detector

Fast Interaction Trigger (FIT)

The Fast Interaction Trigger (FIT) [75] will be a new sub-detector of ALICE expectedto match and even exceed the functionality and performance (fast event triggering min-imum bias luminosity and charged-particle multiplicity measurements) currently secured

44 Chapter 2 ALICE at the CERN LHC

by three ALICE sub-detectors the T0 the V0 and the FMD detectors The location ofFIT will be similar to that of the current V0 and T0 modules with sensors on both sidesof the Interaction Point (IP) The restrictions imposed by the desired functionality tightspace requirements and the need to minimize the material in the vicinity of the inter-action point have narrowed the choice of detector technologies for FIT to either plasticscintillator- andor Cherenkov radiator

ALICE O2 (ALICE Online-Offline)

After the LHC LS2 the Pb-Pb collision interaction rate will be approximately 50 kHzSince the ALICE physics program will focus on untriggerable signals a continuous read-out will be required in order for all events to be recorded The resulting data throughputfrom the detector has been estimated to be larger than 1 TBs for PbminusPb events roughlytwo orders of magnitude more than in Run 1 and Run 2 To minimize the costs and therequirements of the computing system needed for data processing and storage ALICE isdeveloping a new Computing Framework for Runs 3 and 4 called ALICE Online-Offline(ALICE O2) [76] This framework is designed for a maximal reduction of the data volumeread out from the detector as early as possible during the data-flow

Chapter 3

Data Sample Selection andIntegrated Luminosity Evaluation

Summary31 Data Sample Event and Track Selection 45

32 Integrated Luminosity Evaluation 46

321 F inorm Calculation 47

322 The MB Trigger Cross Section 50

323 Lint Evaluation 51

31 Data Sample Event and Track SelectionThe analysis presented in this thesis is based on a data sample collected by ALICE in2016 in pp collisions at

radics = 13 TeV amounting to asymp 26 times 108 events recorded with

a dimuon trigger This is the largest data sample recorded with the low-pT threshold atsim 05 GeVc as of today (September 2017)

The ALICE data taking is organized into two levels at the first level data are orga-nized into periods each one characterized by the same detector and beam configurationsat the second level data within a given period are further organized into runs each onespanning the interval of two consecutive stops in the data acquisition1 Runs retained forthe analysis are selected on the basis of the quality assurance conditions defined for themuon spectrometer These conditions imply the good operation of all detectors involvedin the analysis of the muon data (muon tracking chambers muon trigger chambers SPDlayers of the ITS V0 and T0) The full list of runs used for the present analysis is reportedin appendix A

The Minimum-Bias (MB) trigger condition for the considered data sample is givenby the logical AND of the signals given by the two V0 detectors (V0AND) [48] Eventscontaining a muon pair are selected by means of a specific dimuon trigger based on thedetection of two muon candidate tracks in the trigger system of the muon spectrometerin coincidence with the MB condition Due to the intrinsic momentum cut imposed bythe detector only muons with pTmicro amp 05 GeVc manage to leave a signal in the triggerchambers Both unlike-sign and like-sign dimuon triggers were collected the like-sign

1 The data acquisition can be stopped either because of beam-related or detector-related issues

46 Chapter 3 Data Sample Selection and Integrated Luminosity Evaluation

trigger sample was downscaled by a factor that varied from run to run according to theinstantaneous luminosity

Background events not coming from beam-beam interactions are rejected by perform-ing an offline selection based on the timing information from the V0 detectors Moreoverit is requested that at least one SPD tracklet contributes to the vertex reconstructed bythe ITS

Track reconstruction in the muon spectrometer is based on a Kalman filter algo-rithm [43 77 78] Muon identification is performed by requiring the candidate track tomatch a track segment in the trigger chambers (trigger tracklet) This request selectsmuons with pTmicro amp 05 GeVc and as a consequence significantly affects the collectedstatistics for dimuons with invariant mass 1 GeVc2 and pT 1 GeVc A harder pro-grammable pT threshold can be imposed on single muons when defining the trigger condi-tions according to the specific physics target it was not the case for the data consideredin the present analysis for which the trigger condition was based on any trigger-matchedmuon Due to the geometrical acceptance of the muon spectrometer the pseudo-rapidityselection minus400 lt ηmicro lt minus250 on the muon tracks is imposed where ηmicro is defined in thelaboratory frame in order to remove the tracks close to the acceptance borders of thespectrometer where the acceptance drops abruptly Muon pairs are built combining twomuon tracks that satisfy the cuts mentioned above

The invariant mass spectrum was obtained both for Opposite-Sign (OS) and Like-Sign (LS) muon pairs the latter being considered for background subtraction relatedpurpose It should be noted that the OS component coming from the LS triggers wassafely neglected in the analysis so that only LS pairs were extracted from the LS-triggeredevents they were upscaled run by run by the inverse of the downscaling factor appliedin the data taking

32 Integrated Luminosity EvaluationThe integrated luminosity for the considered data sample was evaluated as Lint =NMBσMB where NMB is the equivalent number of MB events for the analyzed eventsample and σMB the MB trigger cross section The value of NMB was obtained by usingthe following formula

NMB =sumi=run

F inorm timesN i

MUL (31)

where the N iMUL is the number of events fulfilling the unlike-sign dimuon trigger condi-

tion (MUL given by the presence of at least two tracklets in the muon trigger systemof opposite sign both satisfying the single-muon pT-trigger condition) and F i

norm is thenormalization factor to convert the number of MUL events in the analyzed sample to theequivalent number of MB events In the present analysis two conditions are consideredto estimate the number of MB events

bull The first condition (in the following referred to as ldquoV0rdquo) is theCINT7-B-NOPF-MUFAST one This condition is defined by the coincidence oftwo signals in the V0-A and -C sub-detectors with the requirement that the

32 Integrated Luminosity Evaluation 47

coincidence actually comes from a valid beam-beam interaction (B-NOPF) It is alsorequired that the detectors implied in the definition of the MUL trigger conditionare also included in the readout for the considered M B events this is guaranteedby the composition of the specific MUFAST trigger cluster containing the SPDMUON_TRK MUON_TRG T0 V0 and AD detectors

bull The second condition (in the following referred to as ldquoT0rdquo) is based on the coinci-dence of the above condition CINT7-B-NOPF-MUFAST and the level-0 trigger condition0TVX defined by the coincidence of two signals in the T0-A and -C sub-detectors

321 F inorm Calculation

Three methods are usually considered to compute the Fnorm factor run by run one basedon the counting scaler information (online method) and two based on the reconstructeddata (offline methods)

Pile-Up correction

Regardless of the method one needs to estimate the pile-up contribution in order toproperly correct the estimation of NMB The pile-up correction factor (PU) is defined fora given run i as

PU i = microi

1minus eminusmicroi

microi = minus ln1minus FMBi

purity times L0biMB

Di timesN icolliding times fLHC

where

bull fLHC is the frequency of one bunch in the LHC (11245 Hz)

bull N icolliding is the number of colliding bunches

bull Di is the run duration as given by the Central Trigger Processor (CTP)

bull L0biMB is the scaler input of the level-0 trigger for the considered MB condition

bull FMBipurity is the purity factor associated to the considered MB condition

The purity factor for a generic trigger condition X is computed offline as the fractionof physics-selected (PS) X-trigged events [79] divided by the total number of X-triggedevents

FXipurity = N i

X(PS)N iX(ALL) (32)

In the case of the ldquoT0rdquo MB condition the purity factor is considered equal to 1Figure 31 shows the evolution of the purity factor for all the periods involved in thisanalysis and for the MUL and the ldquoV0rdquo MB trigger conditions

Figure 32 shows the evolution of the pile-up correction factor for the periods involvedin this analysis and for the two conditions considered for the estimate of the number ofMB events

48 Chapter 3 Data Sample Selection and Integrated Luminosity Evaluation

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

0

02

04

06

08

1

Purity factor for MUL

Purity factor for V0 MB condition

B TeyssierWork Thesis

Figure 31 Purity factor for the periods f to p in chronological order

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Pile

-Up

corr

ectio

n fa

ctor

1

105

11

115T0 evaluation

V0 evaluation

B TeyssierWork Thesis

Figure 32 Pile-Up correction for the periods f to p in chronological order

Fnorm Evaluation with Online Method

The online method for the evaluation of the Fnorm factor is based on the information ofthe L0b scaler inputs for the MUL and MB triggers conditions In this case F i

norm iscomputed for a given run i as

F inorm = PU i times FMBi

purity times L0biMB

FMULipurity times L0biMUL

(33)

where FXipurity is the purity factor associated to the events selected by the trigger condition

X This method does exploit the full event sample in the analyzed data The run-by-run

32 Integrated Luminosity Evaluation 49

evolution of the F inorm factor evaluated with this method is given in figure 33 both for

the ldquoV0rdquo and ldquoT0rdquo MB conditions

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Nor

mF

0

2

4

6

310times

method Online V0NormF

method Online T0NormF

B TeyssierWork Thesis

Figure 33 Normalization factor for the periods f to p in chronological order evaluated with theonline method both for the ldquoV0rdquo and ldquoT0rdquo MB conditions

Offline Methods

The offline methods are based on the comparison between the number of minimum biasevents in a given data sample and the number of minimum bias events in the same datasample satisfying at the same time the trigger condition of the analyzed events at thelevel-0 For the first offline method the following formula is used for a given run i

F inorm = PU i times MBi

(MBamp0MUL)i (34)

where

bull MBi is the number of physics-selected MB events

bull (MBamp0MUL)i is the number of physics-selected MB events also fulfilling the MULtrigger condition at the level-0

The run-by-run evolution of the F inorm factor evaluated with this method is given in

figure 34 both for the ldquoV0rdquo and ldquoT0rdquo MB conditionsThe second offline method is based on the formula

F inorm = PU i times MBi

(MBamp0MSL)i timesMSLi

(MSLamp0MUL)i (35)

where

50 Chapter 3 Data Sample Selection and Integrated Luminosity Evaluation

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Nor

mF

0

2

4

6

8

10

12310times

method Offline 1 V0NormF

method Oflline 1 T0NormF

B TeyssierWork Thesis

Figure 34 Normalization factor for the periods f to p in chronological order evaluated with the firstoffline method both for the ldquoV0rdquo and ldquoT0rdquo MB conditions

bull MSLi is the number of physics-selected events satisfying the single-muon triggercondition (MSL given by the presence of at least one tracklet in the muon triggersystem passing the all-pT single-muon threshold) in coincidence with the ldquoV0rdquo MBcondition

bull (MSLamp0MUL)i is the number of physics-selected MSL events (see above) also satis-fying the MUL trigger condition at the level-0

bull (MBamp0MSL)i is the number of physics-selected MB events also satisfying the MSLtrigger condition at the level-0

The run-by-run evolution of the F inorm factor evaluated with this method is given in

figure 35 both for the ldquoV0rdquo and ldquoT0rdquo MB conditionsThe relative rate of the MSL trigger condition relative to the MB and the MUL ones is

larger than the relative rate of the MUL trigger condition to the MB one this guaranteesthis second offline method to profit from a larger event sample resulting in a smallerstatistical uncertainty As expected the results from the two offline methods agree withinthe error bars

322 The MB Trigger Cross SectionThe ldquoMBrdquo cross section σMB was measured with a van der Meer scan for both theldquoV0rdquo and ldquoT0rdquo MB condition and found to be 578plusmn 12 mb for the ldquoV0rdquo conditionand 301plusmn 06 mb for the ldquoT0rdquo condition [80] As reported in [80] ldquowhen the LHC isoperated with isolated-bunch-based filling schemes the two detectors provide indepen-dent measurements of the luminosity with a total uncertainty of 23 When the LHC isoperated with bunch trains the V0-based luminosity is affected by non-trivial systematiceffects in this case the total uncertainty on the luminosity measured with T0 is 34rdquo

32 Integrated Luminosity Evaluation 51

2536

59

2541

2825

4378

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

Nor

mF

0

2

4

6

8

10

12310times

method Offline 2 V0NormF

method Offline 2 T0NormF

B TeyssierWork Thesis

Figure 35 Normalization factor for the periods f to p in chronological order evaluated with thesecond offline method both for the ldquoV0rdquo and ldquoT0rdquo MB conditions

It should be noted that these values refer to the pp data taking of 2015 since thecorresponding results from the van der Meer scan of 2016 (when the data considered inthe present analysis were taken) is not available yet We thus currently assume a 5additional systematic uncertainty on σMB accounting for any possible difference betweenthe efficiency of the detectors involved in the MB trigger conditions between 2015 and2016

323 Lint EvaluationTo obtain the value of Lint for the data taking periods considered in this present analysisone has to assume a reference MB condition and a reference method for the evaluationof Fnorm From equation (31) one can expect that for a given MB condition the valuesof Fnorm coming from the online and offline methods discussed above agree between eachother to give the same estimation of NMB Moreover the definition of the integratedluminosity Lint = NMBσMB implies that the ratio between the NMB(V0) and NMB(T0)and then the ratio between Fnorm(V0) and Fnorm(T0) should be consistent with the ratiobetween σMB(V0) and σMB(T0) As one can see by comparing figures 33 to 35 thethree evaluation methods give compatible estimations for Fnorm However the expectedratio between the ldquoV0rdquo and ldquoT0rdquo estimations of Fnorm is only observed with the onlinemethod For this reason the online method (which also profits from the smaller statisticaluncertainties) is retained for the evaluation of the Lint value to be used for the presentanalysis

The resulting values of Lint are 844plusmn 000(stat)plusmn 042(syst) pbminus1 and904plusmn 000(stat)plusmn 452(syst) pbminus1 respectively when the ldquoT0rdquo and ldquoV0rdquo MBconditions are considered The ldquoT0rdquo MB condition assuring the most stable referenceis finally retained and considered in the present analysis

Chapter 4

Monte Carlo Simulations

Summary41 Light-Meson Decays 53

411 Kinematical Distributions 54412 Dalitz Decays 54413 Two-Body Decays 57

42 Dimuons from Open Heavy-Flavor Decays 60421 PYTHIAndash FONLL Comparison 61422 Decay Chain Length in the Open Heavy-Flavor Processes 62

This thesis work is devoted to the study of light-meson production decaying in two-muon (dimuon) channel The dimuon mass range of interest for this study goes fromthe production threshold (Mmicromicro = 2mmicro) to 15 GeVc2 and is named Low-Mass Region(LMR) This region gives access to the dimuon decays of the light vector (ρ ω and φ)and pseudo-scalar (η and ηprime) mesons discussed in section 41 In addition to these decaysa correlated dimuon continuum is also present in the LMR this contribution is treated insection 42 in terms of open charm and beauty processes

For each process discussed in the following the underlying physics is reviewed andthe main details of the corresponding MC simulations are given All the MC simulationsperformed in this thesis used GEANT3 as transport code

41 Light-Meson DecaysThe properties of the light mesons contributing to the LMR through their dimuon de-cays are reported in table 41 These mesons contribute to the LMR with two types ofdecays the two-body decays and the three-body (Dalitz) decays which will be discussedseparately in the following section All the light-meson decays involved in the LMR aresimulated with the AliGenMUONLMR parametric generator

As can be seen from the quark composition reported in table 41 the ρ and ω mesonscan be used as reference for particle production in the (ud) quark sector while strangenessproduction can be accessed via φ meson (and to a lesser extent η and ηprime mesons)measurement The physical width of the ρ meson significantly larger than one of theother particles contributing to the LMR corresponds to the life time of sim 13 fmc thismakes the ρ an ideal probe of in-medium modifications in the case of QGP productiongiven that a large fraction of the observed ρ mesons would decay inside the hot medium

54 Chapter 4 Monte Carlo Simulations

Particle Pole Mass [MeVc2] Width [MeVc2] Quark Compositionη 547862plusmn 0018 (131plusmn 005) middot 10minus3 1radic

6

(uu + ddminus 2ss

)ρ 77526plusmn 025 1491plusmn 08 1

2

(uuminus dd

)ω 78265plusmn 012 849plusmn 008 1

2

(uu + dd

)ηprime 95778plusmn 006 0198plusmn 0009 1radic

3

(uu + dd + ss

)φ 1019461plusmn 0019 4266plusmn 0031 ss

Table 41 Property of light-mesons involved in the dimuon mass spectrum values taken from [4]

411 Kinematical DistributionsThe kinematics parametrization of the light mesons in the AliGenMUONLMR generator areprovided by a pT-y distribution estimated by PHOJET [81 82] (based on a Dual PartonModel combined with perturbative QCD)

412 Dalitz DecaysAmong the light mesons reported in table 41 the η ω and ηprime mesons give a sizableDalitz decay contribution to the LMR The involved decay channels are summarized intable 42

Process Branching Ratio (BR)ηrarr micro+microminusγ (31plusmn 04) middot 10minus4

ωrarr micro+microminusπ0 (13plusmn 06) middot 10minus4

ηprime rarr micro+microminusγ (108plusmn 027) middot 10minus4

Table 42 Dalitz decay processes in the LMR and the branching ratios used in the analysis

The Feynman diagram corresponding to the Dalitz decay under discussion are shownin figure 41 In the considered processes the parent mesons decay electromagnetically intoone virtual photon with mass M and a third body (real photon or π0) with the virtualphoton converting into a muon pair

η

γlowast

microminus

micro+

γ

1(a) ηrarr micro+microminusγ

ω

γlowast

microminus

micro+

π0

1(b) ωrarr micro+microminusπ0

ηprime

γlowast

microminus

micro+

γ

1(c) ηprime rarr micro+microminusγ

Figure 41 Feynman diagrams of the Dalitz decays of interest for the dimuon LMR

The ALICE muon spectrometer is not equipped for detecting neither the real photonnor the π0 emitted within the Dalitz decays discussed here these decays are identified by

41 Light-Meson Decays 55

]2c [GeV-micro+microM0 01 02 03 04 05 06 07 08

- micro+ micro

MdN

d

0

5

10

15

20

610times (gen)γ-micro+micro rarr η

(a) η

]2c [GeV-micro+microM0 02 04 06 08 1

- micro+ micro

MdN

d

0

2

4

6

610times (gen)0π-micro+micro rarr ω

(b) ω

]2c [GeV-micro+microM0 02 04 06 08 1 12

- micro+ micro

MdN

d

0

1

2

3

4

5610times (gen)γ-micro+micro rarr η

(c) ηprime

Figure 42 Generated dimuon mass distribution of Dalitz decay integrated in full phase space

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

γmicromicrorarrη for -micro+micro)ε times(A

(a) η

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

0πmicromicrorarrω for -micro+micro)ε times(A

(b) ω

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

γmicromicrorarrη for -micro+micro)ε times(A

(c) ηprime

Figure 43 Acceptance times efficiency of Dalitz decay

]2c [GeV-micro+microM0 01 02 03 04 05 06 07 08

- micro+ micro

MdN

d

0

005

01

015

02

610times (rec)γ-micro+micro rarr η

(a) η

]2c [GeV-micro+microM0 02 04 06 08 1

- micro+ micro

MdN

d

0

20

40

60

80

100

310times (rec)0π-micro+micro rarr ω

(b) ω

]2c [GeV-micro+microM0 02 04 06 08 1 12

- micro+ micro

MdN

d

0

20

40

60

80

310times (rec)γ-micro+micro rarr η

(c) ηprime

Figure 44 Reconstructed dimuon mass distribution of Dalitz decay integrated in full phase space

56 Chapter 4 Monte Carlo Simulations

looking at the mass distribution of the dimuons coming from the virtual photon conversionFor this reason it is important to have a theoretical description of the shape of suchmass distributions they can be computed in pure QED under the hypothesis of a point-like electromagnetic transition vertex with the deviation from the real transition vertexquantified by a form factor |F (M2)|2 see Equations (41) to (43)

dΓ (ηrarr micromicroγ)dM = 2M 2

3α

π

Γ (ηrarr γγ)M2

(1minus M2

m2η

)3 (1 +

2m2micro

M2

)

timesradicradicradicradic(1minus 4m2

micro

M2

) ∣∣∣Fη (M2)∣∣∣2

(41)

dΓ (ωrarr micromicroπ0)dM = 2M α

3πΓ (ωrarr γπ0)

M2

(1 +

2m2micro

M2

)radicradicradicradic(1minus 4m2micro

M2

)

times(1 + M2

m2ω minusm2

π0

)2

minus 4m2ωM

2

(m2ω minusm2

π0)2

32 ∣∣∣Fω (M2)∣∣∣2

(42)

dΓ (ηprime rarr micromicroγ)dM = 2M 2

3α

π

Γ (ηprime rarr γγ)M2

(1minus M2

m2ηprime

)3 (1 +

2m2micro

M2

)

timesradicradicradicradic(1minus 4m2

micro

M2

) ∣∣∣Fηprime (M2)∣∣∣2

(43)

where the π0 η ω and ηprime pole masses are taken from the PDG tables [4] and the formfactors are expressed by the pole-parametrization for the η and ω mesons and from aBreit-Wigner form for the ηprime meson∣∣∣Fη (M2

)∣∣∣2 = 1(1minus M2

Λ2η

)2 (44)

∣∣∣Fω (M2)∣∣∣2 = 1(

1minus M2

Λ2ω

)2 (45)

∣∣∣Fηprime (M2)∣∣∣2 = m4

0

(m20 minusM2)2 +m2

0Γ20 (46)

For the η andω form factors the corresponding Λ parameter is taken from a recent analysison p-A NA60 data [83] while for the ηprime form factor the parameters m0 = 0764 GeVc2

and Γ0 = 0102 GeVc2 are extracted from a fit on the Lepton-G data [84] The invariantmass distributions Equations (41) to (43) are implemented in the description of theDalitz decays in the AliGenMUONLMR generator together with the definition of the formfactors Equations (44) to (46) This allows one to extract a properly distributed value ofthe virtual photon invariant mass to be used to simulate the decays ηrarr γlowastγ ωrarr γlowastγ

and ηprime rarr γlowastγ from here the full kinematics of the virtual photon can be extractedallowing in turn the kinematics of the muon pair to be evaluated

41 Light-Meson Decays 57

Figure 42 shows the generated dimuon mass distribution for the three Dalitz decaysof interest here The ηprime mass distribution (figure 42c) shows a characteristic enhancementcorresponding to the ρω peak given by the transition form factor which can be easilyinterpreted in terms of the Vector Meson Dominance model [84] For each decay the pTand y dependence of the product of geometrical acceptance and reconstruction efficiency(A times ε) is shown in figure 43 As expected the phase space coverage at low-pT is moreimportant for the Dalitz decays allowing for larger values of the dimuon invariant massFor the ηrarr micro+microminusγ decay which is the reference process for the extraction of the η-mesonsignal (Atimes ε)micro+microminus is negligible for pT

micromicro 05 GeVc putting a strong constraint in theavailable phase space for the η-meson measurement

Figure 44 shows the reconstructed dimuon mass distribution for each Dalitz decayintegrated over minus400 lt y lt minus250 and 00 lt pT lt 100 GeVc These shapes enter asingredients in the hadronic cocktail fit (discussed in section 52) imposing their profiles tobe sufficiently smooth for each phase space interval considered in the analysis since theseshapes extend over a large mass range and are not easily parameterizable a significantlylarge MC statistics is needed especially when (Atimes ε)micro+microminus is particularly low

413 Two-Body DecaysThe two-body decays of interest for the present thesis work are listed in table 43 withthe corresponding branching ratios For the ω rarr micro+microminus and φ rarr micro+microminus decays thebranching ratios are taken as the average (weighted by the corresponding uncertainty) ofthe available measurements of BR(micro+microminus) and BR(e+eminus) assuming lepton universality inorder to reduce the final uncertainty

Process Branching Ratio (BR)ηrarr micro+microminus (58plusmn 08) middot 10minus6

ρrarr micro+microminus (455plusmn 028) middot 10minus5

aωrarr micro+microminus (728plusmn 014) middot 10minus5

bφrarr micro+microminus (2954plusmn 0030)middot 10minus4

a The value reported in this table for the ω is the weighted average measurement of BR(ωrarr l+lminus)The BR(micro+microminus) is (90plusmn 31) middot 10minus5

b The value reported in this table for the φ is the weighted average measurement of BR(φ rarr l+lminus)The BR(micro+microminus) is (287plusmn 019) middot 10minus4

Table 43 Two-body decay processes in the LMR and the branching ratios used in the analysis

The decay of the vector mesons ρ ω and φ into two muons is mediated by a virtualphoton V rarr γlowast rarr micro+microminus (see figures 45b to 45d) The decay of the pseudo-scalar ηmeson into two muons is a 4th order electromagnetic process (see figure 45a) mediatedby two virtual photons where the micro+ coming from one γlowast and the microminus coming from theother γlowast are contracted

The two-body decays are implemented in the AliGenMUONLMR generator approximatingthe narrow mass line shapes of the η ω and φ mesons with a Dirac delta distributiondefined at the resonance pole mass since their physical widths are negligible with respect

58 Chapter 4 Monte Carlo Simulations

η

γlowast

microminus

γlowast

micro+

1(a) ηrarr micro+microminus

ργlowast

microminus

micro+

1(b) ρrarr micro+microminus

ωγlowast

microminus

micro+

1(c) ωrarr micro+microminus

φγlowast

microminus

micro+

1(d) φrarr micro+microminus

Figure 45 Feynman diagrams of two-body decays of the light neutral meson η ρ ω and φ

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

1

2

3

4

5

610times (gen)-micro+micro rarr ρ

Figure 46 Generated mass distribution for the ρrarr micro+microminus process see equation (47)

to the detector mass resolution On the contrary for the ρ meson due to its natural largemass distribution the following parametrization is used [8385]

dNdM =

α2m4ρ

3 (2π)4

radic1minus 4m2

micro

M2

(1 + 2m2

micro

M2

) (1minus 4m2

π

M2

)32

(m2ρ minusM2

)2+m2

ρΓ2ρ(M)

(2πMT )32 eminusMTρ (47)

with a mass-dependent width

Γρ(M) = Γ0ρmρ

M

M2

4 minusm2micro

m2ρ

4 minusm2micro

32

= Γ0ρmρ

M

(q

q0

)3

(48)

where the Γ0ρ is the full resonance width and mρ the resonance mass pole taken from [4]This distribution is shown in figure 46 one can appreciate the peculiar profile of this lineshape covering practically the whole LMR

For each decay the pT and y dependence of Atimes ε is shown in figure 47 As expectedthe phase space coverage at low-pT becomes larger as the mass of the meson increases

41 Light-Meson Decays 59

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrη for -micro+micro)ε times(A

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrρ for -micro+micro)ε times(A

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrω for -micro+micro)ε times(A

]c [GeVT

p0 2 4 6 8 10

y4minus

35minus

3minus

25minus

3minus10

2minus10

1minus10

micromicrorarrφ for -micro+micro)ε times(A

Figure 47 Acceptance times efficiency of two body decay

(a) ηrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1

- micro+ micro

MdN

d

0

005

01

015610times (rec)-micro+micro rarr η

(b) ωrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

01

02

03

04

610times (rec)-micro+micro rarr ω

(c) ρrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

002

004

006

008

01

012

610times (rec)-micro+micro rarr ρ

(d) φrarr micro+microminus

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

- micro+ micro

MdN

d

0

01

02

03

04

610times (rec)-micro+micro rarr φ

Figure 48 Reconstructed dimuon mass distribution of two body decays integrated in full phasespace

60 Chapter 4 Monte Carlo Simulations

For the ω rarr micro+microminus decay which is the reference process for the extraction of the ω-meson signal (Atimes ε)micro+microminus is significant down to pT = 00 GeVc in the rapidity rangeminus400 lt y lt minus325 and down to pT asymp 20 GeVc towards the y = minus250 limitFor the φ rarr micro+microminus decay from which φ-meson signal can be extracted (Atimes ε)micro+microminus issignificant down to pT = 00 GeVc in the rapidity range minus400 lt y lt minus300 and downto pT asymp 20 GeVc towards the y = minus250 limit

Figure 48 shows the reconstructed dimuon mass distribution for each two-body decayintegrated over minus400 lt y lt minus250 and 00 lt pT lt 100 GeVc These shapes enter to-gether with the Dalitz one discussed in the previous section as ingredients in the hadroniccocktail fit From the mass distributions in figure 48 the detector mass resolution for thenarrow η ω and φ mesons can be estimated performing a Gaussian fit on the centralpart of the peaks the value are found to be ση asymp 458 MeVc2 σω asymp 489 MeVc2 andσφ asymp 520 MeVc2

42 Dimuons from Open Heavy-Flavor DecaysIn the low mass region in addition to the Dalitz and two-body decays of light neutralmesons two other processes may contribute namely the so-called open charm and openbeauty processes In these processes a correlated muon pair comes from the simultaneoussemi-muonic decay of two correlated heavy-flavor hadrons coming from the hadronizationof a heavy qq pair These processes are illustrated in figure 49 for the open charm andbeauty

c

DX

micro

c

D

micro

X

b

BX

micro

b

B

micro

X

Figure 49 Illustration of open heavy-flavor decays

The open charm and beauty processes are generated with the PYTHIA6 MC gener-ator PYTHIA generates the primary cc (or bb) quark pairs performs the correspondinghadronization as well as the decay of the heavy flavor hadrons The decays of the long-livedparticles possibly appearing in the decay chains of the heavy-flavor hadrons are performedby the transport code GEANT3 To save CPU time the PYTHIA6-based parametric gener-ator (AliGenCorrHF) is used developed within the AliRoot framework generating oneheavy-flavor pair per event to further optimize the simulation the first heavy hadronpair is produced in the rapidity hemisphere of the muon spectrometer

The simulation of the open charm and beauty processes depends of the knowledgeof the kinematic distributions of the primary cc (or bb) quark pairs determining the

42 Dimuons from Open Heavy-Flavor Decays 61

kinematics of the first hadron pair and thus the shape of the mass distribution of finalmuon pairs The cc and bb kinematic distributions are known with large uncertainties atforward rapidity at the LHC energies due to the lack of measurements of heavy flavorhadrons in this kinematic range For this reason we also considered a second modelFONLL [86] (for Fixed-Order plus Next-to-Leading Log) giving an alternative descriptionof the cc and bb kinematic distributions based on some perturbative calculation madepossible by the large mass of the charm and beauty quarks To optimize the CPU timefor the simulations based on the FONLL predictions a reweighting is applied on the ex-isting simulations based on the ratio between the (pT minus y) parton distributions given byPYTHIA and FONLL The reweighting has been performed considering three FONLL kinemat-ics distributions the central prediction the prediction corresponding to the upper limitassociated to the uncertainty range and the prediction corresponding to the lower limitassociated to the uncertainty range in this way we can compare up to four hypothesesfor the input of the open charm and beauty processes

The discussion presented in the following section applies to the open charm processas well as to the open beauty one similarly each figure will include two panels the ldquoardquoone dedicated for the open charm case the ldquobrdquo for the beauty case

421 PYTHIAndash FONLL ComparisonTo estimate the difference between the available hypotheses on the input parton kinemat-ics the ratio of the FONLL partonic pT distributions (corresponding to the central valueand the upper-lower limits of the uncertainty range) to the PYTHIA one is shown in Fig-ure 410 In this figure the ratio corresponding to FONLL central value is represented insolid curve and the ratios corresponding to the upper and lower limits of FONLL uncertaintyrange are represented as an uncertainty band As can one see the ratio of the centralFONLL value to PYTHIA deviates significantly from unity the deviation becomes strongerwhen the upper-lower limits of the FONLL prediction are considered The PYTHIA-FONLLdisagreement is stronger for the charm than for the beauty

It is now interesting to investigate how the difference between the PYTHIA and FONLLpredictions for the input kinematic distributions of the cc and bb quark pairs affects theshape of the reconstructed dimuon mass spectra which will be used as ingredients ofthe fit of the data To do so the reconstructed mass spectra corresponding to the fouravailable MC inputs are compared in figure 411 PYTHIA FONLL central value FONLLupper value and FONLL lower value For the sake of comparison the four distributionsare normalized to the same integral In the case of the open charm process figure 411athe differences between the models are clearly visible accross the considered mass rangewhile for the open beauty process figure 411b there is a remarkable agreement betweenthe curves A possible way to quantify the uncertainty on reconstructed dimuon massdistributions of open charm and beauty due to the model assumed for the input partonicdistribution is to evaluate the FONLL over PYTHIA ratios as a function of the dimuon massas shown in figure 412

As expected the ratios for the open beauty process stay significantly closer to unitythan the open charm process By inspecting the graphs one can estimate the uncertaintyon the open charm shape to be of the order of 15 in the LMR significantly increasing

62 Chapter 4 Monte Carlo Simulations

]c [GeVT

p0 2 4 6 8 10

ratio

FO

NLL

Pyh

tia fr

om C

harm

0

1

2

3

(a) charm

]c [GeVT

p0 2 4 6 8 10

ratio

FO

NLL

Pyh

tia fr

om B

eaut

y

0

1

2

3

(b) beauty

Figure 410 Partonic pT distribution ratio FONLL [87] over PYTHIA the black curve represents thereference value of the ratio and the red hatching represents the error according to FONLL model

]2c [GeV-micro+microM0 1 2 3 4 5

au

0

10

20

30

40

50

3minus10times

FONLL

PYTHIA

FONLL - max

FONLL - min

(a) open charm

]2c [GeV-micro+microM0 1 2 3 4 5

au

0

10

20

30

40

3minus10timesFONLL

PYTHIA

FONLL - max

FONLL - min

(b) open beauty

Figure 411 Reconstructed dimuon mass coming from open heavy flavor semi-leptonic decays

towards large masses while from the open beauty shape the uncertainty in the LMR stayswithin 5 We will come back to these uncertainties in section 52 where the fit routineallowing the signal extraction will be discussed

422 Decay Chain Length in the Open Heavy-Flavor Processes

In the open heavy-flavor processes considered in this section the number of decay stepsbetween the initial parton and the final muon (noted decay chain afterwards) can bepotentially large resulting in a weakening of the kinematic correlation between the initialand the final states If the decay chains associated to the two final muons are sufficiently

42 Dimuons from Open Heavy-Flavor Decays 63

]2c [GeV-micro+microM0 1 2 3 4 5

0

02

04

06

08

1

12

14

FONLL over Pythia

FONLL - Min over Pythia

FONLL - Max over Pythia

(a) open charm

]2c [GeV-micro+microM0 1 2 3 4 5

09

095

1

105

FONLL over Pythia

FONLL - Min over Pythia

FONLL - Max over Pythia

(b) open beauty

Figure 412 Dimuon mass spectrum ratio from FONLL (reference min and max value) over PYTHIA

long the initial qq correlation could be substantially washed out in the final muon pairFor this reason it is interesting to study the distribution of the decay chain length (λmicro)in simulated open charm and beauty processes defined as the number of decay stepsbetween the initial parton and the final muon

-microlength 0 2 4 6 8 10

+ microle

ngth

0

2

4

6

8

10

1

10

210

310

410

510

(a) open charm

-microlength 0 2 4 6 8 10

+ microle

ngth

0

2

4

6

8

10

1

10

210

310

410

510

(b) open beauty

Figure 413 micro-chain for open heavy flavor at generated level

In figure 413 the correlation between the λmicro of the positive and negative muons isshown for the dimuons coming from the open charm and beauty simulations In thisfigure on can clearly see that λmicro can get as large as 10 As expected the average λmicrovalues are larger for the open beauty process than the open charm one due to the largerphase space available

Since the λmicro distributions extend over relatively large ranges one can wonder which isthe impact of having short or long muon decay chains on the shape of the dimuon invariant

64 Chapter 4 Monte Carlo Simulations

]2c [GeV-micro+microM0 1 2 3 4 5

au

4minus10

3minus10

2minus10

1minus10

4le plusmnmicroλ = 4 amp plusmnmicroλ 3le plusmnmicroλ = 3 amp plusmnmicroλ 2le plusmnmicroλ = 2 amp plusmnmicroλ 1le plusmnmicroλ = 1 amp plusmnmicroλ

(a) open charm

]2 [GeVc-micro+microM0 1 2 3 4 5

au

4minus10

3minus10

2minus10

1minus10

4le plusmnmicroλ = 4 amp plusmnmicroλ 3le plusmnmicroλ = 3 amp plusmnmicroλ 2le plusmnmicroλ = 2 amp plusmnmicroλ 1le plusmnmicroλ = 1 amp plusmnmicroλ

(b) open beauty

Figure 414 Generated dimuon mass coming from open heavy flavor semi-leptonic decays withparticular λmicro

mass distributions To do so in figure 414 the dimuon mass distributions are shown forfour particular λmicro+λmicrominus combinations As expected shorter decay chains correspond toharder mass distributions

We thus verified that the shape of the invariant mass profile of the open charm andbeauty dimuons depends of the length of the decay chains of the two muons This meansthat to properly reproduce the dimuon mass profile of the open charm and beauty com-ponents in the data we have to correctly reproduce the distribution of the decay lengthchains for the simulated dimuons Now this is not a problem as long as any dimuon froman open charm or beauty process is retained both in the data and in the MC Howeverthe data considered for the signal extraction are obtained by subtracting the combinato-rial background from the raw dimuon spectrum implying that we should retain in theMC the correlated dimuons only But the correlation of a muon pair coming from anopen charm or beauty process is progressively lost as the length of the decay chains of thetwo muons increases and it is extremely hard mdash in terms of analysis strategy and CPUtime mdash to estimate and take such an effect into account in the MC simulations Thisintroduces a source of uncertainty when describing the correlated continuum in the datawith the superposition of the open charm and beauty simulations

Chapter 5

Signal Extraction

Summary51 Combinatorial Background Evaluation and Subtraction 65

511 The Event Mixing Technique 66

512 Monte Carlo Validation of the Event Mixing Technique 67

513 The Combinatorial Background Estimation 68

52 Invariant Mass Fit Procedure 70

521 Specific Constraints on the Hadronic Cocktail Components 71

522 Correlated Continuum Treatment 72

523 A Few Examples of Hadronic Cocktail Fits 76

In this chapter the main source of background for the dimuon decay channel will bediscussed as well as the strategy considered for the extraction of the signals of interestFrom now on following a convention widely used within the ALICE muon communityrapidity values are given in the positive axis justified by the symmetry of the pp collisionsystem with respect to y = 0

51 Combinatorial Background Evaluation and Sub-traction

The present analysis is based on the study of the OS dimuon invariant mass spectrumDimuons are built by combining muon pairs coming from the same event (see section 31)Since dimuons coming from the light-neutral meson decays of interest for this work cannotbe disentangled from the other dimuon sources any pair of muons must be consideredwhen building the dimuon invariant mass spectrum This implies that a fraction of theconsidered dimuons actually comes from randomly paired uncorrelated muons this frac-tion of dimuons is conventionally named ldquocombinatorial backgroundrdquo The ratio betweenthe correlated and uncorrelated dimuon components varies significantly according to thecollision system the considered mass region and the apparatus performance In the low-mass region the ALICE muon spectrometer gives correlated over uncorrelated dimuonratios as large as few units (in pp collisions) and as low as few percents (in the mostcentral Pb-Pb collisions)

66 Chapter 5 Signal Extraction

511 The Event Mixing TechniqueThe combinatorial background for the OS dimuons has been evaluated using an eventmixing technique based on the reasonable assumption that the LS dimuon sample doesnot contain correlated muon pairs The mixing event technique implies the creation of asample of uncorrelated dimuon formed by pairing two muons coming from two differentevents In the following we will identify dimuons built from a same event with the labelldquodirrdquo and dimuons built from different events with the label ldquomixrdquo The event mixingtechnique is illustrated in figure 51

Event A

micro+A1

microminusA2

Event B

microminusB1

microminusB2

micro+B3

Opposite Signmicro+A1micro

minusB1

micro+A1micro

minusB2

microminusA2micro+B3

Like Sign ++micro+A1micro

+B3

Like Sign minusminusmicrominusA2micro

minusB1

microminusA2microminusB2

Figure 51 Illustration of mixing events with two events one with two muons and one with threemuons

The mixed OS dimuon sample is used in the event mixing technique to estimatethe OS combinatorial background in the direct OS dimuon sample for this reason onlyevents sharing same global properties are considered in the event mixing Among theseglobal properties one can cite the z-position of the primary vertex the charged-particlemultiplicity or in nucleus-nucleus collisions the orientation of the event plane In the ppcollisions considered in the present analysis the impact of classifying the events accordingto the z-position of the primary vertex and the charged-particle multiplicity was testedresulting in no difference with respect to the case in which the events are mixed regardlessof their global properties1

The shape of the invariant mass distribution expected for the OS uncorrelated dimuonsis taken for each kinematic range considered in the analysis directly from the outputdistribution Nmix

+minus (M) given by the event mixing technique The normalization is fixed tothe integral of the distribution 2R(M)

radicNdir

++(M) middotNdirminusminus(M) extracted from the data

Nmix+minus (M) minusrarr Nmix

+minus (M)

int2R(M)

radicNdir

++(M) middotNdirminusminus(M) dMint

Nmix+minus (M) dM

(51)

The integral of the 2R(M)radicNdir

++(M) middotNdirminusminus(M) distribution is indeed a good estimation

of the total number of the OS dimuons in the data as long as the LS dimuon samples1 This is valid as long as the analysis is integrated over the mentioned global properties in particular

the charged-particle multiplicity

51 Combinatorial Background Evaluation and Subtraction 67

Ndir++ and Ndir

minusminus do not contain any correlated muon pair The R factor accounts for thepossible differences between the acceptances of ++ minusminus and +minus muon pairs

R(M) = A+minus(M)2radicA++(M) middotAminusminus(M)

(52)

The R factor was estimated as

R(M) = Nmix+minus (M)

2radicNmix

++ (M) middotNmixminusminus (M)

(53)

where Nmix++ and Nmix

minusminus is the number of dimuons for the given sign combination theacceptances are evaluated with the mixing

512 Monte Carlo Validation of the Event Mixing TechniqueA Monte Carlo approach was considered to check the quality of the combinatorial back-ground estimation as follows Events containing two muons were simulated with thekinematics extracted randomly and independently for the two muons from some pT andy distributions taken from the data The azimuthal angle of each muon was randomlydrawn within flat distribution and the charges also randomly attributed In this waythe OS sample of the direct dimuons from this MC event sample could be assumed to bepurely combinatorial by construction We could thus check if the procedure describedabove was able to reproduce its mass shape and normalisation To do this we appliedto this same MC sample the event mixing technique to obtain the mass shape with thecorrect normalization

The ratio RMCdirmix between the true and estimated mass shapes of the combinatorial

OS dimuons was thus extracted for each kinematics interval considered in the analysisSeveral options are possible for the trigger class of the events considered in the eventmixing procedure The considered trigger classes are based on the ldquoV0rdquo trigger conditionsee section 31 to which a specific condition is added based on the response of the muontrigger

bull ldquoMULrdquo based on the presence of at least two tracklets in the muon trigger systemof opposite sign both passing the low-pT single-muon threshold

bull ldquoMLLrdquo based on the presence of at least two tracklets in the muon trigger systemof like sign both passing the low-pT single-muon threshold

bull ldquoMSLrdquo based on the presence of at least one tracklet in the muon trigger systempassing the low-pT single-muon threshold

bull ldquoMSL-onlyrdquo it is defined by this logical combination of trigger conditionsMSL ampMUL ampMLL so it is the condition which minimizes the impact of the dimuontrigger condition on the retained events

The trigger condition of the events considered for the event mixing technique waschosen as the one maximizing the flatness of RMC

dirmix Figures 52 and 53 show that the

68 Chapter 5 Signal Extraction

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeVmicromicroM

0 1 2 3 4 5 6

Dir

ect

Mix

ed

06

08

1

12

14

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

lt 40y25 lt

c lt 100 GeVT

p00 lt = 13 TeVsALICE pp

MUL

MLL

MSL

Figure 52 Comparison of background evalua-tion ratio direct over mixed for ldquoMULrdquo ldquoMLLrdquoand ldquoMSLrdquo conditions

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeVmicromicroM

0 05 1 15 2 25 3

Dir

ect

Mix

ed

09

095

1

105

11

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

MSL

MSL amp MUL amp MLL

Figure 53 Comparison of background evalu-ation ratio direct over mixed for ldquoMSLrdquo andldquoMSL-onlyrdquo conditions

best results are obtained considering events satisfying the ldquoMSL-onlyrdquo condition withldquoMSLrdquo condition also giving a reasonably small deviation of RMC

dirmix from unity On thecontrary the worst performance is associated to the MLL and MUL trigger conditions

The combinatorial background mass shape evaluated for the real data was correctedfor the RMC

dirmix ratio To get rid of the statistical fluctuations due to the limited availableMC sample this ratio is parametrized by the following function before being used tocorrect the data

f(M) = A eminusaM minusB eminusbM +C (54)

where all the parameters are imposed to be positive except C This correction is performedindependently in each (pT y) phase space interval considered in the analysis

513 The Combinatorial Background Estimation

Having validated the method for the evaluation of the combinatorial background it is nowpossible to use it for isolating the dimuon correlated signal in the data Following the resultof the MC validated presented in the previous section the ldquoMSL-onlyrdquo events are used asinput for the event mixing technique The typical mass dependence of the R-factor (ratiobetween the acceptance of LS and OS muon pairs) defined in equation (52) and estimatedas equation (53) is shown in figure 54 for the phase space interval 10 lt pT lt 100 GeVcand minus400 lt y lt minus250 In this same kinematics interval the comparison between theraw dimuon and the combinatorial background is shown in figure 55 The correspondingisolated dimuon correlated signal is shown in figure 56 forMmicromicro lt 100 GeVc2 where thepeaks of the Υ(1S) ψ(2S) and Jψ resonances can be observed and in figure 57 for thelow-mass region where the peaks of the φ and ρω two-body decays are visible togetherwith the structure of the η Dalitz decay

51 Combinatorial Background Evaluation and Subtraction 69

]2c [GeVmicromicroM0 2 4 6 8 10

R

0

02

04

06

08

1

12

lt 1000T

p100 lt

lt - 250y- 400 lt

B TeyssierWork Thesis

Figure 54 The R factor for the data integratedin 10 lt pT lt 100 GeVcand minus400 lt y lt minus250

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 2 4 6 8 10

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

dNd

M

210

310

410

510

610

raw mass spectrum

mass spectrummixOS

B TeyssierWork Thesis

Figure 55 Raw data between 250 lt y lt 400and 10 lt pT lt 100 GeVc

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

]2c [GeVmicromicroM0 2 4 6 8 10

]2 c [d

imuo

ns p

er 2

5 M

eV

micromicrodN

dM

210

310

410

510

610 B TeyssierWork Thesis

Jψ

ψ (2S)

Υ (1S)

Figure 56 Signal after subtraction of combina-torial background in mass range between 02 to100 GeVc2

0 02 04 06 08 1 12 140

01

02

03

04

05

610timesB Teyssier

Work Thesis

ρω

φ

Figure 57 Signal after subtraction of combina-torial background in mass range between 02 to15 GeVc2

70 Chapter 5 Signal Extraction

The combinatorial background estimation and subtraction is particularly challengingat very low pT where the signal-over-background ratio is smaller (as small as asymp 1 at theφ peak) In order to appreciate how the signal can nevertheless be extracted down tovery low pT in figure 58 (top panels) the raw data with the associated combinatorialbackground are shown for 00 lt pT lt 02 GeVc in the rapidity intervals where theacceptance is non-negligible (the most forward region see figures 43 and 47) Thecorresponding isolated signal is shown in the same figure (bottom panels)

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

25310times

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 375 lt y lt 400

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15310times

B TeyssierWork Thesis

(e) 350 lt y lt 375

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310timesB Teyssier

Work Thesis

(f) 375 lt y lt 400

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310timesB Teyssier

Work Thesis

Figure 58 Rapidity evolution of signal and combinatorial background shapes for 00 lt pT lt

02 GeVc

52 Invariant Mass Fit ProcedureAfter subtraction of the uncorrelated background the next step in the analysis is theextraction of the signals of interest from the dimuon correlated invariant mass spectrumin this specific case this means counting how many dimuons from the η rarr micro+microminusγω rarr micro+microminus and φ rarr micro+microminus decays can be extracted from the data for each of the pT-yintervals considered in the analysis For this step the dimuon correlated invariant massspectrum is decomposed into the expected sources composing the hadronic cocktail (two-body and Dalitz decays of light neutral mesons see section 41) via a fit procedure also

52 Invariant Mass Fit Procedure 71

including a description of the correlated continuum component

521 Specific Constraints on the Hadronic Cocktail Compo-nents

In the fit procedure considered in this analysis for the extraction of the signals of interestspecific constraints have been imposed to the components of the hadronic cocktail inorder to reduce the number of degrees of freedom fixing the minor processes (in terms ofreconstructed dimuons) to the major ones Each considered constraint has been also takenas a contribution in the evaluation of the systematics on the signal extraction discussedin section 61

Fixing the relative branching ratios of two-body and Dalitz decays for the ηand ω meson mdash The η and ω mesons contribute to the hadronic cocktail with twodecay channels ηrarr micro+microminusγ and ηrarr micro+microminus for the η and ωrarr micro+microminusπ0 and ωrarr micro+microminus

for the ω Since the branching ratios of each channel is known from the literature thenormalizations of the two-body and Dalitz decay modes can be fixed to each other (as longas the quality of the data does not allow for an independent measurement of the relativebranching ratios) This constraint has been technically implemented for the η meson byconsidering the normalization of the ηrarr micro+microminusγ process has a free parameter and fixingthe ηrarr micro+microminus contribution to it for the ω meson the normalization of the ωrarr micro+microminus

process has been left as a free parameter the contribution of the ω rarr micro+microminusπ0 decaybeing fixed to it For each particle the process associated to the free parameter is the onemore clearly identifiable in the invariant mass profile of the data The relevant branchingratios are listed in tables 42 and 43

Fixing the σηprimeσφ cross-section ratio mdash The contribution of the ηprime Dalitz decayaccounts for a very small fraction of the total reconstructed dimuon mass spectrum forthis reason and because of its continuum shape having no dominant structure apart fromthe broad peak at ρ mass (due to the contribution of the ρ meson to the ηprime form factorsee section 412) the fit procedure is not sensitive to this contribution Consequently thenormalization of the ηprime rarr micro+microminusγ process has been set by fixing the ηprime cross-section tothe cross-section of one of the particles giving a major contribution to the invariant massspectrum namely the φ meson The reference value for the σηprimeσφ cross-section ratio hasbeen evaluated with PHOJET to be 3151 in the rapidity window 25 lt y lt 40 integratedover pT This ratio has been rescaled in each pT-y interval considered in the analysisaccording to the kinematic distributions of the two particles also given by PHOJET

Fixing the σρσω cross-section ratio mdash Due to the broad line shape of the ρ mesonand the limited mass resolution of the detector for the superimposed ω rarr micro+microminus peakthe ρ rarr micro+microminus contribution cannot be easily disentangled in the fit procedure For thisreason the normalization of the ρrarr micro+microminus contribution has been set to the ωrarr micro+microminus

one by fixing the σρσω cross-section ratio The reference value for this ratio has beentaken as 10 from previous measurements [88ndash90]

72 Chapter 5 Signal Extraction

Due to the mass resolution of the ω peak the distinction of the ω and ρ two-bodycontribution is not obvious So it is better to enslave the ρ two-body component to theω to increase the stability of the fit The ratio of the production cross-section of ρω ismeasured to 10 in several previous experiments [88ndash90]

522 Correlated Continuum TreatmentSeveral choices can be considered for the description of the correlated continuum as dis-cussed below As discussed in section 42 the main sources in the correlated dimuoncontinuum are the open charm and beauty processes However as also discussed in sec-tion 42 the evaluation of the MC template of the invariant mass shape of the open charmand beauty dimuons is affected by potentially non-negligible uncertainties according tothe considered input for the cc and bb kinematics and the real degree of correlation of thefinal state muons Moreover one as to consider the possibility of having some residualuncertainty from the combinatorial background subtraction and a possible dimuon com-ponent from correlated light-flavor hadron decays On the basis of these considerationstwo approaches have been tested for the description of the correlated continuum

In the fit process for treating the underlying physics continuum we assume that themain source of this continuum is based on the open heavy-flavor where the way to obtainthe shapes of open charm and beauty are described in section 42 Two possible ways forusing these shapes in the fit process one based on the full description of all processes theother based on a phenomenological approach for the correlated continuum and realisticdescription of processes are considered

The ldquocharm+beautyrdquo approach mdash This approach is based on three assumptions

1 The correlated continuum has only two components open charm and beauty

2 The shapes of the dimuon invariant mass templates for the open charm and beautyprocesses are known with negligible uncertainties (with the same precision as thetemplates for the hadronic cocktail processes)

3 The ratio between the open beauty and the open charm dimuon components isknown (together with its pT and y dependence at the specific energy considered inthe analysis) either from measurements or from tuned models like FONLL or PYTHIA

In this approach the correlated continuum description is associated to one free parameterThe only available measurements for the cc and bb cross-section at forward rapidity comefrom LHCb [3891ndash93] the ratio σbbσcc is (594plusmn 055) middot 10minus2 in good agreement withthe central value of the FONLL prediction (645 middot 10minus2) [86 87]

When considering this approach in the description of the correlated continuum non-negligible tensions between data and MC can be found according to the specific phasespace interval considered These tensions increase towards mid-rapidity while are almostnegligible for the most forward rapidity intervals An example is given in the left-columnplots of figures 59 and 510 where the data-MC comparison is shown for the six y intervals

52 Invariant Mass Fit Procedure 73

considered for the analysis in the pT interval 20 lt pT lt 22 GeVc The same trend isobserved in almost all the considered pT intervals

As a matter of fact these tensions induce an indirect bias on the extraction ofthe signals of interest for the analysis particularly important for the extraction of theω rarr micro+microminus signal For this reason this approach is probably not well-fitted for thisspecific analysis aiming to simultaneously extract the η rarr micro+microminusγ ω rarr micro+microminus andφrarr micro+microminus signals

The semi-empirical approach mdash This new approach has been developed after con-sidering the major limitations of the ldquocharm+beautyrdquo approach in describing the dataover the full rapidity interval available The main difference with respect to the previousapproach is the fact that we abandon any strict physical interpretation of the correlatedcontinuum describing it with an empirical profile flexible enough to saturate the tensionbetween data and MC ensuring a robust extraction of the signals of interest for the anal-ysis This is achieved by describing the correlated continuum by means of two (or more)free parameters each controlling the normalization of an independent empirical shapeThe specific shape of these independent components is not really important still one hasto use sufficiently different mass shapes to ensure enough freedom on the total profile ofthe continuum

Two variants of this semi-empirical approach have been tested in this analysis

bull A 2-component description of the correlated continuum In this case an obviouschoice is to take the two components as the invariant mass distributions of OSdimuons from open charm and open beauty simulations2 This choice allows one tocombine the required smoothness of the continuum invariant mass shape with thekinematical constraints typical of a reconstructed dimuon mass distribution closeto the low-mass threshold this would not have been (easily) achievable with anytrivial combination of analytical parametric functions

bull A 3-component description of the correlated continuum In this variant we add athird component to the two components already considered in the previous case areasonable choice is to take this third component to have the profile of the combi-natorial background evaluated in each pT and y interval considered in the analysis

The results of the data description with these two variants of the semi-empirical ap-proach are shown in figures 59 and 510 in the center and right panels respectively forthe 2- and the 3-component description of the correlated continuum As one can see the2-component description already fixes the tension between data and MC found with theldquocharm+beautyrdquo approach in the full y range Nevertheless the addition of the third de-gree of freedom allowed by the 3-component description of the correlated continuum stillimproves the extraction of the signal in some specific cases see for instance the extractionof the φrarr micro+microminus signal in figures 59b and 59c For this reason the 3-component variantof the semi-empirical approach has been retained as the reference method for the signalextraction for the present analysis

2 It should be clear that in this semi-empirical approach the physical interpretation of any of the twocomponents taken separately is meaningless and must be avoided

74 Chapter 5 Signal Extraction

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 275y250 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 275y250 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 275y250 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 300y275 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 300y275 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 300y275 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(g) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(h) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(i) 300 lt y lt 325

Figure 59 Signal fit for 20 lt pT lt 22 GeVc and various y intervals The first figure of each linecorresponding to the method with the full description of processes the second and third figures ofeach line corresponding to the hybrid method with two or three components respectively

52 Invariant Mass Fit Procedure 75

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6310times

lt 400y375 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(g) 375 lt y lt 400

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6310times

lt 400y375 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(h) 375 lt y lt 400

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6310times

lt 400y375 lt

c lt 22 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 22 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 220 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(i) 375 lt y lt 400

Figure 510 Signal fit for 20 lt pT lt 22 GeVc and various y intervals The first figure of eachline corresponding to the method with the full description of processes the second and third figuresof each line corresponding to the hybrid method with two or three components respectively

76 Chapter 5 Signal Extraction

523 A Few Examples of Hadronic Cocktail FitsThe detailed breakdown of the MC sources involved in the fit procedure is shown infigure 511 where the data sample considered in the present analysis is integrated over250 lt y lt 400 and 10 lt pT lt 100 GeVc The structures of the η rarr micro+microminusγω rarr micro+microminus and φ rarr micro+microminus processes considered for the estimation of the η ω and φyields are observed to shine out over the underlying continuum Here as well as in thefits presented in the rest of the document the red profile is the sum of the MC sourcesThe uncertainty on the total MC profile is evaluated by combining the uncertainties onthe normalization of each considered source For the processes whose normalization isleft free in the fit this uncertainty is the statistical one resulting from the fit procedureitself for the other processes we propagate the systematic uncertainty on the parameters(branching ratios or cross section ratios) which fix their normalizations to those of thefree processes

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

01

02

03

04

05

610times

γmicromicro

rarrη

γmicromicrorarrη

micromicrorarrη

micromicrorarrρ0πmicromicrorarrω

micromicrorarr

ω

micromicrorarrφ

continuumcorrelated

lt 40y25 lt

c lt 100 GeVT

p10 lt = 13 TeVsALICE pp

lt 400y250 lt

c lt 1000 GeVT

p100 lt = 13 TeVsALICE pp

lt 40y25 lt

c lt 100 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y250 lt

c lt 1000 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 40y25 lt

c lt 100 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y250 lt

c lt 1000 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

Figure 511 Example of hadronic fit in 250 lt y lt 400 and 10 lt pT lt 100 GeVc

The shape of the dimuon invariant mass spectrum changes significantly according tothe considered pT-y interval In particular at very low-pT and towards central rapiditythe acceptance constraints imposed by the detector deplete the mass spectrum near thekinematic threshold For this reason some of the processes are not measurable in specificregions of the phase space as it could be expected by inspecting the pT-y profiles of the(Atimes ε) reported in figures 43 and 47 In addition at high-pT one observes a decrease ofthe ratio of the hadronic cocktail over the correlated continuum which could be attributedto the decrease of the ratio of the light flavor sources (composing the hadronic cocktail)over the heavy flavor ones (contributing to the correlated continuum) The full evolutionof the dimuon invariant mass spectrum profile as a function of pT and y can be appreciated

52 Invariant Mass Fit Procedure 77

by considering the plots in appendix C In figure 512 we report a few examples illustratingthe discussed point

(a) 00 lt pT lt 02 GeVcand 375 lt y lt 400

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 04 lt pT lt 05 GeVcand 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 20 lt pT lt 22 GeVcand 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

310times

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 40 lt pT lt 45 GeVcand 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 70 lt pT lt 80 GeVcand 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 80 lt pT lt 100 GeVcand 250 lt y lt 275

Figure 512 A few examples of hadronic fit in several pT and y intervals

Chapter 6

Systematics Evaluation

Summary61 Systematics on the Signal Extraction 80

611 Relative Branching Ratio of two-body and Dalitz Decays for the ηand ω Mesons 80

612 σηprimeσφ Cross-Section Ratio 80

613 σρσω Cross-Section Ratio 81

614 Upper limit of the fit 81

615 The correlated continuum shape 81

616 Systematic Uncertainty Computation 82

62 Systematics from the MC input 82

63 Systematics on Trigger Efficiency 83

631 Evaluation of the Trigger Response Function 83

632 Results 84

64 Systematics on Tracking Efficiency 85

641 Preliminary Check 85

642 Tracking Efficiency Evaluation 86

643 MC parametrization 88

644 Results 89

65 Summary of Systematic Uncertainty 89

In this chapter all the systematics sources of the present analysis are presented Twomain groups of systematics uncertainties have been studied

bull the sources contributing to the systematics uncertainty on the signal extraction

bull the sources contributing to the systematics on the (Atimes ε) evaluation

In the first group we include the uncertainties on the parameters involved in thefit procedure (see section 52) relative branching ratios cross-section ratios correlatedcontinuum shape fit range In the second group we include the uncertainties on thekinematic input of the MC simulations on the tracking efficiency and the trigger response

80 Chapter 6 Systematics Evaluation

61 Systematics on the Signal ExtractionIn order to define the systematics tests on the signal extraction a reference scenario hasbeen defined based on the reference values of the parameters involved in the fit procedureFor each parameter one or more alternative values have been considered each systematictest is defined by the variation of one parameter only while the others are kept fixedto their reference value In total 10 systematic tests have been considered the totalsystematic uncertainty on the number of η rarr micro+microminusγ ω rarr micro+microminus and φ rarr micro+microminus

dimuons was taken as the standard deviation of the values resulting from these tests

Syst test reference value alternative value(s)BR ηrarr micro+microminus PDG PDG minus1σ PDG +1σBR ωrarr micro+microminusπ0 PDG PDG minus1σ PDG +1σRatio σηprimeση 0295 minus50 +50Ratio σρσω 10 minus10 +10Upper fit limits 15 GeVc2 20 GeVc2

Templates for thecorrelated contin-uum components

ccrarr micromicro from PYTHIAbbrarr micromicro from PYTHIA

OS from evt mix (data)

ccrarr micromicro from FONLLbbrarr micromicro from FONLL

OS from combinatorial bkg (MC)

Table 61 Summary of systematics tests

611 Relative Branching Ratio of two-body and Dalitz Decaysfor the η and ω Mesons

This systematics test reflects the uncertainty on the ratio between the branching ratio ofthe two-body and Dalitz decay channel of the η and ω mesons In this analysis this testwas implemented by varying the branching ratio of the η rarr micro+microminus and ω rarr micro+microminusπ0

processes by plusmn1σ where σ is the uncertainty on the measurement reported by the PDG(shown in tables 42 and 43) resulting in four independent alternative fits on the data

The variation of the ηrarr micro+microminus branching ratio was found to have a negligible impacton the extraction of η rarr micro+microminusγ and φ rarr micro+microminus signals and a limited impact on theextraction of the ωrarr micro+microminus signal of the order of 1 On the contrary the variation oftheωrarr micro+microminusπ0 branching ratio by plusmn1σ has an average impact of plusmn3 for the extractionof ηrarr micro+microminusγ and ωrarr micro+microminus signals and negligible for the φrarr micro+microminus signals

612 σηprimeσφ Cross-Section Ratio

The ratio σηprimeσφ was varied by plusmn50 to take into account the general lack of mea-surements for this ratio and the differences between the predictions from the availablephenomenological models PYTHIA6 and PHOJET The impact of the considered plusmn50 vari-ation has been observed to be in average ∓2 for the ωrarr micro+microminus signal and negligiblefor the φrarr micro+microminus and ηrarr micro+microminusγ signal

61 Systematics on the Signal Extraction 81

613 σρσω Cross-Section RatioThe uncertainty on the σρσω ratio has been taken from the existing measurements atlower energy [88ndash90] The absence of any strong theoretical argument in favor of animportant energy dependence of this ratio allowed us to take a plusmn10 for the associateduncertainty As expected the impact of this plusmn10 variation is non-negligible only for theextraction of theωrarr micro+microminus signal which is affected by a corresponding ∓2 uncertainty

614 Upper limit of the fitThe lower limit of the invariant mass fit range has been set to the 2mmicro kinematic thresholdin order to be sensitive to the full structure of the η rarr micro+microminusγ decay For the upperlimit a reference value has been set at 15 GeVc2 this value is a trade-off betweenbeing sensitive to the full width of the φ rarr micro+microminus peak and limiting the impact of thecontinuum region between the φ and Jψ resonance where no signal of interest for thelight-neutral mesons can be extracted To study the systematic uncertainty linked to thechoice of the upper limit of the fit range an alternative value has also been defined at20 GeVc2 The corresponding average impact on the extraction of the signals of interestis -3 -12 and -4 respectively for the η rarr micro+microminusγ ω rarr micro+microminus and φ rarr micro+microminus

signals

615 The correlated continuum shape

]2c [GeVmicromicroM0 02 04 06 08 1 12 14

[au

]micromicro

dNd

M

0

5

10

15

20

25

3minus10times

from OS mixing

(PYTHIA)bfrom b

(PYTHIA)cfrom c

(a) Reference

]2c [GeVmicromicroM0 02 04 06 08 1 12 14

[au

]micromicro

dNd

M

0

5

10

15

20

25

3minus10times

microfrom OS MC uncorr

(FONLL)cfrom c

(FONLL)bfrom b

(b) Alternative

Figure 61 Normalized shape of continuum templates

The shape of the correlated continuum is determined by the fit by optimizing therelative weight of three invariant mass templates as explained in section 522 To eval-uate the systematic uncertainty associated to the choice of this set of templates analternative set of templates have been considered The alternative templates correspond

82 Chapter 6 Systematics Evaluation

to the reconstructed open charmbeauty dimuons generated with the lower limit of theFONLL prediction range (offering the largest deviation from the corresponding referencetemplates see figure 412) and to the OS dimuons from the MC simulations of uncor-related muons already considered for the validation of the event mixing technique (seesection 512) Considering the alternative set of templates has an average impact of minus1for the ηrarr micro+microminusγ 2 for the ωrarr micro+microminus and 9 for the φrarr micro+microminus signals

616 Systematic Uncertainty ComputationAs already mentioned the systematic uncertainty on the signal extraction is computedseparately for the η rarr micro+microminusγ ω rarr micro+microminus and φ rarr micro+microminus processes as the standarddeviation of the distribution of value obtained from the systematic tests described above

σ2 = 1N

testssumi

(xi minus 〈x〉)2 (61)

where xi is the outcome of the i-th systematic test out of the N available tests andthe expectation value 〈x〉 is taken as the outcome of the reference fit This approach isjustified by the assumption that for each source of systematics the associated uncertaintycan be assumed to be Gaussian This evaluation is done for each pT-y interval consideredin this analysis

The global uncertainty on the signal extraction is reported in table 62 for the threesignals extracted with the fit procedure since its value depends on the pT and y intervalthe minimum and maximum values are quoted The average uncertainties correspondingto the considered systematic tests on the signal extraction are also reported in the table

Syst test ηrarr micro+microminusγ ωrarr micro+microminus φrarr micro+microminus

BR ηrarr micro+microminus lt 1 2 2 BR ωrarr micro+microminusπ0 3 3 2 Ratio σηprimeσφ lt 1 3 2 Ratio σρσω 1 2 2 Upper fit limit 5 6 8 Templates for the correlatedcontinuum 6 4 5

Standard deviation from (61) 1 - 22 2 - 12 1 - 16

Table 62 Summary of the systematic tests considered on the signal extraction procedure

62 Systematics from the MC inputThe first source of systematic uncertainty considered for the (Atimes ε) evaluation is thechoice of the input kinematic distributions assumed in MC simulations for the generatedη ρ ω ηprime and φ mesons see section 411 The reference choice being the correlated

63 Systematics on Trigger Efficiency 83

pT-y input from PHOJET the alternative MC input has been based on parametrized non-correlated pT and y distributions form PYTHIA6 The corresponding systematic uncer-tainty has been evaluated for each pT and y interval considered in this analysis by takingthe difference of the (Atimes ε) value estimated with the reference and the alternative MCinputs The corresponding average impact on the extraction of the signals of interest is5 55 and 1 respectively for the ηrarr micro+microminusγ ωrarr micro+microminus and φrarr micro+microminus signals

63 Systematics on Trigger Efficiency

The systematics on the trigger efficiency has been determined by comparing the proba-bility of reconstructing dimuons of a given kinematics with two different trigger responsefunctions one obtained from the data and the other from MC simulations The standardprocedure to estimate the systematic uncertainty from the trigger response function canbe summarized as follows

bull Fit the ratio low-pTA-pT obtained dividing the pT distribution of single muonsmatching the low-pT trigger condition by the pT distribution of single muons match-ing the A-pT condition (see paragraph e on section 223) This ratio is evaluatedboth in data and in realistic MC simulations and the corresponding fits define thetrigger response function

bull Select muons matching the A-pT trigger condition in the MC simulation of a specificdimuon signal and weigh each of them (according to their pT) by either the dataor the MC trigger response function

bull Extract the number of reconstructed dimuons under the two assumptions of thetrigger response function The difference is the systematics uncertainty of the triggerefficiency

631 Evaluation of the Trigger Response Function

The definition of the trigger response function given above cannot be used in the presentanalysis because in the considered data set the low-pT and the A-pT trigger matchingconditions coincide Therefore an alternative definition of the trigger response function isadopted here namely the ratio low-pTAll where the denominator is the pT distributionof All reconstructed muons imposing no trigger matching condition

Unfortunately this new definition of the trigger response function cannot be safelyapplied to the data because the All muon sample is contaminated by a non-negligiblehadronic component In this case one can still estimate the low-pTAll for the datastarting from the ratio of the corresponding MC ratio through a dataMC conversionfactor This conversion factor is defined as the ratio between the trigger response functionslow-pTA-pT of data and MC estimated in a dataset (B) as close as possible to the one(A) considered in the present analysis and characterized by different thresholds for the

84 Chapter 6 Systematics Evaluation

low-pT and A-pT trigger matching conditions

low-pT

All

∣∣∣∣∣data

A

(pT) = low-pT

All

∣∣∣∣∣MC

A

(pT)timeslow-pTA-pT

∣∣∣dataB

(stimes pT)low-pTA-pT

∣∣∣MC

B(stimes pT)

(62)

with the pT dependence of the trigger response functions in the reference dataset B beingldquostretchedrdquo by the s factor

s = pcutT (MC B)pcutT (MC A) (63)

where pTcut(MC x) is defined as the pT value for which the trigger response function

(low-pTAll or low-pTA-pT respectively for the datasets A and B) reaches half the dif-ference between the maximum and minimum This approach is correct as long as twoassumptions are valid

bull the trigger response per local board does not change with time

bull the relative difference dataMC between the low-pTA-pT trigger response func-tions from data and MC does not change when considering the low-pTAll triggerresponse functions

The low-pTA-pT trigger response functions defining the dataMC conversion factorin equation (62) can be replaced by a parametrization given by the function

F (pT pcutT σ) = 1 + p0 times

erfpT minus pcut

Tsradic

2σs

minus 1 (64)

based on the three free parameters p0 pcutT and σIn the present analysis the reference dataset B has been assumed to be the 2015 Pb-Pb

dataset (restricted to the peripheral collisions in the 60-100 centrality class) taken atradics = 502 TeV this choice is also used in other dimuon analyses based on the pp dataset

atradics = 5 TeV and the p-Pb dataset at radicsNN = 5 mdash 816 TeV

632 ResultsThe two versions of the trigger re-weighting described above produced two alternativeestimations of the (Atimes ε) for the three considered processes For each pT-y cell consideredin the analysis we retained the alternative version giving the largest deviation with respectto the reference value this deviation is shown in the form of a ratio in figure 62 Theabsolute deviation of this ratio is taken as the systematic uncertainty on the triggerefficiency the average values of this uncertainty are 2 06 and 1 respectively forthe ηrarr micro+microminusγ ωrarr micro+microminus and φrarr micro+microminus processes In the analysis this uncertaintyhas been evaluated for each specific pT-y cell considered for the extraction of the signalSystematic uncertainty values as large as 30 were tolerated in this analysis this resultedin the exclusion of the (minus350 lt y lt 325 04 lt pT lt 06 GeVc) interval for theηrarr micro+microminusγ signal affected by a systematic on the trigger efficiency larger than 70

64 Systematics on Tracking Efficiency 85

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

06

07

08

09

1

11

12

13

14 RefTrigg-reweight

γmicromicrorarrη ]εtimes[ A

(a) ηrarr micro+microminusγ

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

06

07

08

09

1

11

12

13

14 RefTrigg-reweightmicromicrorarrω ]εtimes[ A

(b) ωrarr micro+microminus

]c [GeVT

p0 2 4 6 8 10

y

4minus

35minus

3minus

25minus

06

07

08

09

1

11

12

13

14 RefTrigg-reweight

micromicrorarrφ ]εtimes[ A

(c) φrarr micro+microminus

Figure 62 Ratio of Atimes ε for original simulation over the re-weighted simulation for estimating thesystematics associated to the trigger efficiency

64 Systematics on Tracking Efficiency

The systematics on tracking efficiency is one of the contributions to the uncertainty on the(Atimes ε) estimation To compute this uncertainty one has to evaluate the ratio betweenthe tracking efficiencies of data and MC

641 Preliminary Check

Before studying the tracking efficiencies in data and MC it must be verified that thestatus of the detector described in the realistic MC simulations is compatible with thestatus of the detector reflected by the data This is done by inspecting the cluster mapsof the tracking chambers in data and MC in this way one can verify whether the deadareas in the data are correctly reproduced in the MC and no additional dead area isintroduced An example of such comparison is shown in figure 63

Another point to be checked is the variation of the high voltage supplied to the track-ing chambers with respect to the value 16 kV corresponding to the nominal operatingconditions During Run 2 indeed some frequent high voltage drops to 14 kV were spot-ted resulting in a degraded efficiency of the chambers Since this intermediate behaviorbetween the full operation and the off status cannot be easily reproduced in MC specificdetector elements being significantly affected by high voltage drops are added to a ldquorejectlistrdquo and excluded from the reconstruction both in data and MC Alternatively when thispathological high voltage behavior only affects a limited fraction of the considered datasample full runs can be excluded it was the case in the present analysis where 4 runsof the LHC16n period were rejected to avoid major discrepancies between data and MC

After checking the agreement between data and MC concerning the detector statusand the behavior of the high voltage it is possible to launch the evaluation of the trackingefficiency both in data and MC

86 Chapter 6 Systematics Evaluation

Figure 63 Comparison between cluster maps of tracking chamber 4 in data (left) and MC (right)

642 Tracking Efficiency EvaluationThe tracking efficiency (εglobal) is computed as the product of the efficiency (εSti) of eachtracking station

εglobal = εSt1 middot εSt2 middot εSt3 middot εSt45 (65)

The fact the efficiencies of stations 4 and 5 are combined together in the efficiency εSt45 isdue to the logic operating mode implemented in the tracking algorithm [7894] requiringone cluster per station for stations 1 2 and 3 and three clusters from the combinedstations 4-5

Ch1 Ch2 Ch3 Ch4 Ch5 Ch6 Ch7 Ch8 Ch9 Ch10

NSt21-1

St1 St2 St3 St4 St5

NSt20-1

NSt21-0

NSt20-0

St45

Figure 64 Sketch showing the arrangement of the chambers into stations and the possible responsesof one station to the passage of a particle

64 Systematics on Tracking Efficiency 87

To evaluate the efficiency of a given station one has to start considering the efficiencyof the chamber composing the station (see section 223 for a more detailed description ofthe muon spectrometer structure) To evaluate the efficiency of each tracking chamberthe assumption is done that its efficiency does not depend on the efficiency of the otherchambers under this assumption the redundancy of the information given by the twochambers of a specific station can be used to determine the efficiency of each chamberseparately Figure 64 shows the possible responses of station 2 to the passage of aparticle Generalizing to the case of an arbitrary station k the reconstructed track canhave a cluster in both chambers (NStk

1-1 ) a cluster either in the first or the second of thetwo stations (NStk

1-0 or NStk0-1 ) or the track does not fulfill the tracking conditions so it is not

reconstructed (NStk0-0 ) Still focusing on station k composed of chamber i and j(= i+ 1)

one can express the number of reconstructed tracks (Ntot each of them crossing stationk due to the conditions imposed by the tracking algorithm) as

Ntot = NStk1-1 +NStk

0-1 +NStk1-0 (66)

Under the assumption that the efficiencies of chambers i and j are independent NStk1-1

NStk1-0 and NStk

0-1 can be expressed as a function of Ntot

NStk1-1 = Ntot middot εChi middot εChj (67)

NStk1-0 = Ntot middot εChi middot (1minus εChj) (68)

NStk0-1 = Ntot middot (1minus εChi) middot εChj (69)

By combining the above equations the efficiencies of chamber i and j are given by

εChi = NStk1-1

NStk1-1 +NStk

0-1εChj = NStk

1-1NStk

1-1 +NStk1-0

(610)

The individual chamber efficiencies can be combined to compute the efficiency of eachstation In the case of the first three stations the efficiency is defined as the probabilityfor a muon to be detected by at least one of the two chambers

εSt1(23) = 1minus(1minus εCh1(35)

) (1minus εCh2(46)

)= εCh1(35) εCh2(46) +

(1minus εCh1(35)

)εCh2(46) + εCh1(35)

(1minus εCh2(46)

) (611)

For the last two stations the efficiency has to be calculated as a whole due to the trackingalgorithm requirements This efficiency is the probability that a muon is detected by atleast three out of the four chambers in the stations the corresponding formula is thegeneralization of equation (611)

εSt45 =10prodi=7

εChi +10sumi=7

(1minus εChi)10prodj=7j 6=i

εChj

(612)

88 Chapter 6 Systematics Evaluation

643 MC parametrization

In order the tracking efficiency estimation in the MC to be reliable the considered para-metric muon generator must be tuned in order to reproduce the reconstructed kinematicsof the single muons measured in pp collisions at

radics = 13 TeV considered in the present

analysis The tuning is performed by means of a recursive procedure illustrated in fig-ure 65 which includes the following steps

1 Run MC simulations of single muons with given input pT and y distributions

2 Compute the (Atimes ε) as a function of pT and y

3 Use the (Atimes ε) to correct the reconstructed muon distributions from data

4 Compute the ratio as a function of both pT and y between the corrected datadistribution and the kinematic distributions considered for the MC input Shouldthis ratio be compatible with one convergence is reached and the procedure isstopped

5 Inject the corrected pT and y data distributions as the new input for MC simulation

until step 4 is equal to one

First Set of MC simulation

MC gen distribMC rec distrib

MC (Atimes ε)Rec

data distrib

Data corr distrib

Datacoor distrib =MC gen distrib

Data corr distrib rarr MC gen distrib

Done

1

2

3 34

No

Yes

51

Figure 65 Illustration of the data driven method used to tune the input distribution of single muon

65 Summary of Systematic Uncertainty 89

644 ResultsTracking efficiency estimations from the data and from the tuned MC simulation areshown in figure 66 as a function of pT y the azimuthal angle ϕ and the run number A2 systematic uncertainty is observed in average for single muon from the comparisonbetween data and MC For the dimuon signals the systematic uncertainty on the trackingefficiency is estimated to be twice the systematics on the single muons in this case thisresults in a 4 systematic uncertainty independent of pT and y

run number

2536

59

2541

28

2543

78

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

effic

ienc

y

0

02

04

06

08

1

Simulation Data

run number2536

59

2541

28

2543

78

2555

15

2561

46

2565

04

2589

19

2602

18

2606

49

2623

99

2640

76

2643

47

EffD

ata

EffS

im

09

1

11

B TeyssierWork Thesis

Figure 66 Tracking efficiency measured in data and in the tuned MC simulation as a function ofrun number

65 Summary of Systematic UncertaintyIn table 63 are summarized the various sources of systematic uncertainties discussed inthis chapter For each of these sources and each signal of interest for this analysis wereport the value of the systematic uncertainty when the uncertainty values depend onthe pT or the y interval their maximum and minimum values are quoted

Syst source η ω φ

Signal extraction 1 - 22 2 - 12 1 - 157 MC input 5 55 1 Trigger efficiency 1 - 31 1 - 24 1 - 25 Branching ratio 13 2 1 Tracking efficiency 4 Luminosity 5

Table 63 Summary of the systematic uncertainty sources contributing to the measurement of theη ρω and φ meson cross-section

Chapter 7

Light Neutral Meson Production

Summary71 Estimation of the Number of Generated Mesons 91

711 The Two-Body Decay Case 91712 The Dalitz Decay Case 92

72 Cross-Section Production for Light Neutral Mesons 93

721 Double-Differential η Meson Production 93722 ρω Meson Production 94723 Double-Differential φ Meson Production 98

This chapter describes the steps followed to convert the reconstructed signal into cross-section for the η ρω and φ mesons The pT dependence of the production cross-sectionis extracted in six y intervals and compared to the predictions of the available modelsIn the case of the φ and ρω mesons the pT dependence of the rapidity-integratedcross-section is also derived allowing for the comparison with the results from existingmeasurements in pp collisions in the same rapidity range

71 Estimation of the Number of Generated MesonsThe very first step after signal extraction consists in correcting the number of recon-structed dimuons for the Atimesε evaluated with the MC simulations discussed in section 41In the case of the two-body decays ρω rarr micro+microminus and φ rarr micro+microminus the information onthe dimuons can be directly converted into the corresponding information on the parentmesons by correcting for the branching ratios of the involved decays In the case of theDalitz decay ηrarr micro+microminusγ an additional step is required to convert the dimuon kinematicsto the η meson one before correcting for the branching ratio

711 The Two-Body Decay CaseAs far as the two-body decays of the ρω and φ mesons are concerned the corrected num-ber of mesons (Nρω and Nφ respectively) corresponding to the reconstructed dimuonsN recmicromicro is given for each pT-y interval considered in this analysis by the following formula

Nρω φ(pT y) =N recmicromicro (pT y)

[Atimes ε]micromicro (pT y) middotBRmiddot ∆pT middot ∆y (71)

92 Chapter 7 Light Neutral Meson Production

where [Atimes ε]micromicro (pT y) is the product of the acceptance and the dimuon reconstructionefficiency evaluated in the specific pT-y cell BR is the branching ratio of the considereddecay channel (see table 43) and ∆pT middot ∆y are the widths of the pT-y cell For theestimation relative to the ρω mesons N rec

micromicro (pT y) [Atimes ε]micromicro (pT y) and the BR arereferred to the ωrarr micro+microminus decay

712 The Dalitz Decay Case

When dealing with the Dalitz decay of the η we start by correcting the number ofreconstructed dimuons for the Atimes ε and the widths of the considered pT-y cell

Ngenmicromicro (pT y) =

N recmicromicro (pT y)

[Atimes ε]micromicro (pT y) middot ∆pT middot ∆y (72)

Contrary to the two-body case the corrected kinematics distribution of the dimuon doesnot coincide with the one of the parent meson due to the Dalitz decay kinematics implyinga third body

)ηyηT

pId(0 50 100 150 200 250 300

)micromicroymicromicro T

pId

(

0

50

100

150

200

250

300

1

10

210

310

410

510

610

710

810

)micromicroy micromicroT

p ηy ηT

pT(

Figure 71 Correlation matrix T(pηT yη pmicromicroT ymicromicro) represented in cell coordinates

72 Cross-Section Production for Light Neutral Mesons 93

So to obtain the correct kinematic distributions of the parent η meson an additionaltransformation is needed

Nηrarrmicromicroγ(pT y) = Tminus1 middot Ngenmicromicro (pT y) (73)

where Tminus1 is the inverse of the matrix encoding the correlation between the kinematics ofthe parent η meson and the one of the dimuon both expressed in terms of pT and y TheT(pηT yηp

micromicroT y

micromicro) is shown in figure 71 each T(pηT yη pmicromicroT y

micromicro) element of the matrix isdefined as the probability of an η meson with a given (pηT yη) kinematics to produce adimuon with a given (pmicromicroT ymicromicro) kinematics so that one can write

Ngenmicromicro (pT y) = Tmiddot Nηrarrmicromicroγ(pT y) (74)

from which equation (73) is derived The row-column indexes of the elements of theTmatrix identify a specific pηT yη and pmicromicroT ymicromicro cell respectively In this specific analysisthe phase space limits considered for both the η and the dimuon are 20 lt y lt 45 and00 lt pT lt 150 GeVc in this way any possible edge effect affecting the numericalproblem will have a limited impact on the phase space covered by the available data

Once the correction expressed by equation (73) is performed the resulting kinematicdistribution is further scaled for the η rarr micro+microminusγ branching ratio in order to obtain thecorrect normalization for the Nη(pT y) distribution

72 Cross-Section Production for Light NeutralMesons

The Nηρωφ(pT y) distributions obtained after correcting for the Atimesε and the branchingratio (and for the meson-dimuon kinematic correlation in the case of the η) must be furthernormalized to the integrated luminosity Lint corresponding to the analyzed data sample(the evaluation of the integrated luminosity is discussed in section 32) This normalizationallows one to obtain the cross-section for the three mesons

d2σ(pT y)dpTdy = Nηρωφ(pT y)times 1

Lint (75)

721 Double-Differential η Meson Production

In figure 72 the pT distributions of the dimuon coming from the η rarr micro+microminusγ decay areshown for the six y interval considered in this analysis These distributions representthe Ngen

micromicro (pT y) input from which the kinematic distribution of the parent meson can beextracted via equation (73) The implementation in the current analysis of the kinematiccorrection based on equation (73) is however still under way for this reason no resulton the η meson cross-section is shown in the rest of the chapter

94 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

ydT

pd η

dN

510

710

910

1110

13100250 lt y lt 275 x 101275 lt y lt 300 x 102300 lt y lt 325 x 103325 lt y lt 350 x 104350 lt y lt 375 x 105375 lt y lt 400 x 10

B TeyssierWork Thesis

Figure 72 Comparison of the pT distribution of η dimuon generated as a function of y

722 ρω Meson ProductionFor the ρω mesons the double-differential pT-y production cross-section has been eval-uated in the available phase space the results are shown in figure 73 as a function ofpT in six y intervals For each y interval the measured cross-section has been comparedto the predictions of PYTHIA8-Monash2013 [95] and PHOJET The comparison is shown inthe panels of figure 74 the two models systematically overestimate by a factor sim 2 thedata in the full accessible pT range for each of the considered y intervals

In figure 75 the y dependence of the production cross-section is shown integratedover the pT range 20 lt pT lt 65 GeVc common to the considered y intervals Thecomparison with the predictions from PYTHIA8-Monash2013 and PHOJET confirms thatthe models overestimate the data by a factor sim 2 Besides the global overestimation thePHOJET prediction seems to provide a better description than PYTHIA8-Monash2013 of they dependence of the data

The ρω production cross-section was also measured in ALICE in pp collisions atradics =

7 TeV integrated over 25 lt y lt 40 as a function of pT in the 10 lt pT lt 50 GeVcrange In order to compare our data to the ones at

radics = 7 TeV the production cross-

section measured in this analysis has been integrated over the full accessible 25 lt y lt 40range As it can be seen from figure 73 the integration over 25 lt y lt 40 was possiblelimited to the 20 lt pT lt 65 GeVc range The comparison between the two energiesshows that the 13 TeV cross-section is larger than the 7 TeV one by a factor sim 2 seefigure 76

72 Cross-Section Production for Light Neutral Mesons 95

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

210

310

410

510

610

0250 lt y lt 275 x 10

1275 lt y lt 300 x 10

2300 lt y lt 325 x 10

3325 lt y lt 350 x 10

4350 lt y lt 375 x 10

5375 lt y lt 400 x 10

B TeyssierWork Thesis

Figure 73 Comparison of the pT distribution of ω meson as a function of y

96 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

375 lt y lt 400

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

3minus10

2minus10

1minus10

1

10350 lt y lt 375

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

325 lt y lt 350

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

300 lt y lt 325

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

275 lt y lt 300

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd

ωσd

2minus10

1minus10

1

10

250 lt y lt 275

Pythia8

PHOJETB Teyssier

Work Thesis

Figure 74 pT distributions of ω meson for various y intervals

72 Cross-Section Production for Light Neutral Mesons 97

y4minus 2minus 0 2 4

[mb]

yωσd

0

05

1

15

2

25

3

(reflected)ω

(measured)ω

Pythia8 - monash2013

Phojet

c lt 65 GeVT

p20 lt

B TeyssierWork Thesis

Figure 75 y distribution of ω meson integrated in 20 lt pT lt 65 GeVc

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσ2 d

3minus10

2minus10

1minus10

1

=7TeVspp at

=13TeVspp at

B TeyssierWork Thesis

Figure 76 pT distribution of ω meson integrated in y and comparison with measurements at7 TeV [43]

98 Chapter 7 Light Neutral Meson Production

723 Double-Differential φ Meson ProductionAs for the ρω mesons the double-differential pT-y production cross-section has beenevaluated for the φ meson too in the available phase space the results are shown infigure 77 as a function of pT in the y intervals considered in the analysis extended at mid-rapidity with the φ rarr K+Kminus measurements [96] The comparison of the data with thepredictions of the PYTHIA8-Monash2013 and PHOJET models is shown for each y intervalconsidered in the analysis in the panels of figure 78 contrary to what observed for theω meson the PYTHIA8-Monash2013 prediction provides a good description of the dataThe PHOJET prediction on the contrary still slightly fails in estimating the normalizationand the shape of the pT dependence of the production cross-section

The y dependence of the production cross-section is shown in figure 79 integratedover the pT range 20 lt pT lt 65 GeVc common to the considered y intervals As one cansee the data points sit between the predictions from PYTHIA8-Monash2013 and PHOJETwhich both slightly fail in describing the shape of the y dependence The results for theφ meson production in the dikaon channel provide an additional point at mid-rapiditywhich could be compared to the forward measurements presented here

Results for the φ meson production cross-section are also available from ALICE mea-surements in pp collisions at

radics = 276 502 7 and 8 TeV integrated over 25 lt y lt 40

as a function of pT in various pT ranges In order to compare our data to the ones atlower energies the φ meson production cross-section measured in this analysis has beenintegrated over the full accessible 25 lt y lt 40 range As it can be seen from figure 77this integration was possible limited to the 20 lt pT lt 65 GeVc range As expected thecross-section at 13 TeV is found to be larger than the measurements at lower energies

The energy dependence of the φ meson production cross-section has been studiedintegrating the present measurement over the y and pT ranges 25 lt y lt 40 and15 lt pT lt 50 GeVc common to the data at the various available energies Theresults are shown in figure 711 compared with the PYTHIA8-Monash2013 and PHOJETprediction the trend as a function of

radics is found to be approximately linear in the con-

sidered energy range with the PHOJET model in good agreement with the data and thePYTHIA8-Monash2013 prediction systematically underestimating the results The analysisstrategy at 13 TeV is being slightly revised in order to reduce the systematic uncertaintyassociated to the integrated cross-section by optimizing the integration procedure namelyintegrating over the rapidity before signal extraction

72 Cross-Section Production for Light Neutral Mesons 99

]c [GeVT

p0 2 4 6 8 10 12

)]c [m

b(G

eV

ydT

pd φσd

4minus10

3minus10

2minus10

1minus10

1

10

210

310

410

510

-1|lt05 x 10y |-

K+ Krarrφ0250 lt y lt 275 x 10

1275 lt y lt 300 x 10

2300 lt y lt 325 x 103325 lt y lt 350 x 10

4350 lt y lt 375 x 10

5375 lt y lt 400 x 10

B TeyssierWork Thesis

Figure 77 Comparison of the pT distribution of φ meson as a function of y extended at mid-rapidityby the φrarr K+Kminus measurements [96]

100 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1375 lt y lt 400

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

350 lt y lt 375

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1325 lt y lt 350

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

300 lt y lt 325

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

275 lt y lt 300

Pythia8

PHOJETB Teyssier

Work Thesis

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσd

3minus10

2minus10

1minus10

1

250 lt y lt 275

Pythia8

PHOJETB Teyssier

Work Thesis

Figure 78 pT distribution of φ meson for various y intervals

72 Cross-Section Production for Light Neutral Mesons 101

y4minus 2minus 0 2 4

[mb]

y φσd

0

01

02

03

04

05

(refkected)φ (dikaon measurement)φ (measured)φ

Pythia8 - monash2013

Phojet

c lt 65 GeVT

p20 lt

B TeyssierWork Thesis

Figure 79 y distribution of φ meson integrated in 20 lt pT lt 65 GeVc extended at mid-rapidityby the φrarr K+Kminus measurements [96]

102 Chapter 7 Light Neutral Meson Production

]c [GeVT

p0 2 4 6 8 10

)]c [m

b(G

eV

ydT

pd φσ2 d

3minus10

2minus10

1minus10

1 =276TeVspp at

=5TeVspp at

=7TeVspp at

=8TeVspp at

=13TeVspp at

lt 40y25 lt

B TeyssierWork Thesis

Figure 710 φ meson pT distribution integrated over 25 lt y lt 40 in pp collisions atradics = 13 TeV

(this analysis) compared to previous measurements at lower energies

72 Cross-Section Production for Light Neutral Mesons 103

B TeyssierWork Thesis

Figure 711 Energy dependence of the φ meson production cross-section in 25 lt y lt 40 and15 lt pT lt 50 GeVc

Conclusions and Perspectives

This work focused on the study of the production cross-section of the η ρω and φmesons This study has been achieved by performing a double-differential pT-y analysisin the phase space available for each meson Results have been compared to the availabletheoretical predictions from the PYTHIA8 and PHOJET models this comparison resultedin a better datamodel agreement for the φ meson than for the ρω meson Moreoverexisting results at several lower collision energies in the same y interval allowed toinvestigate the energy evolution of the production cross-section for the φ meson andlimited to the comparison with the

radics = 7 TeV results for the ρω mesons For the φ

meson the energy evolution of the production cross-section integrated over 25 lt y lt 40and 15 lt pT lt 50 GeVc was found to be approximately linear with the PHOJET modelin good agreement with the data and the PYTHIA8-Monash2013 prediction systematicallyunderestimating the results In a next future the results for the φ meson from thepresent analysis could also be compared to the mid-rapidity measurement performed inALICE in the dikaon channel

The present analysis did not exploit the full potential of the large data sample availablein pp collisions at

radics = 13 TeV which could possibly profit from the combination of the

2016 and 2017 data taking Among the measurements which could still be performedbased on the analysis of the low-mass dimuon region one can cite

bull the study of the multiplicity dependence of the light-neutral meson production

bull the search for strangeness enhancement collective phenomena and azimuthalanisotropies in light-neutral meson production in high-multiplicity pp events

bull the study of the light-neutral meson polarization

Finally beyond the standard dimuon analyses the large pp data sample atradics = 13 TeV

could also be exploited for the search of the first evidence of the η rarr 2micro+2microminus decayfor which only an upper limit is currently available from literature [4] The proximity ofthe η meson mass to the 4mmicro threshold makes the observation of this decay particularlychallenging and sensitive to the description to the combinatorial background

Appendix A

List of Runs

000253659 000253680 000253682 000253748 000253751 000253755 000253756 000253757000253813 000253819 000253825 000253826 000253832 000253834 000253951 000253956000253957 000253958 000253961 000253978

Table A1 Run list for period LHC16f

000254128 000254147 000254148 000254149 000254174 000254175 000254178 000254193000254199 000254204 000254205 000254293 000254302 000254304 000254331 000254332

Table A2 Run list for period LHC16g

000254378 000254381 000254394 000254395 000254396 000254419 000254422 000254476000254479 000254604 000254606 000254608 000254621 000254629 000254630 000254632000254640 000254644 000254646 000254648 000254649 000254651 000254652 000254653000254654 000254983 000254984 000255008 000255009 000255010 000255042 000255068000255071 000255073 000255074 000255075 000255076 000255079 000255082 000255085000255086 000255091 000255111 000255154 000255159 000255162 000255167 000255171000255173 000255176 000255177 000255180 000255182 000255240 000255242 000255247000255248 000255249 000255251 000255252 000255253 000255255 000255256 000255275000255276 000255280 000255283 000255350 000255351 000255352 000255398 000255402000255415 000255440 000255442 000255447 000255463 000255465 000255466 000255467000255469

Table A3 Run list for period LHC16h

000255515 000255533 000255534 000255535 000255537 000255538 000255539 000255540000255542 000255543 000255577 000255583 000255591 000255592 000255614 000255615000255616 000255617 000255618

Table A4 Run list for period LHC16i

108 Appendix A List of Runs

000256146 000256147 000256148 000256149 000256156 000256157 000256158 000256161000256169 000256204 000256207 000256210 000256212 000256213 000256215 000256219000256222 000256223 000256227 000256228 000256231 000256281 000256282 000256283000256284 000256287 000256289 000256290 000256292 000256295 000256297 000256298000256302 000256307 000256311 000256356 000256357 000256361 000256362 000256363000256364 000256365 000256366 000256368 000256372 000256373 000256415 000256417000256418 000256420

Table A5 Run list for period LHC16j

000256504 000256506 000256510 000256512 000256552 000256554 000256556 000256557000256560 000256561 000256564 000256565 000256567 000256589 000256591 000256592000256619 000256620 000256658 000256676 000256677 000256681 000256684 000256691000256694 000256695 000256697 000256941 000256942 000256944 000257011 000257012000257021 000257026 000257028 000257071 000257077 000257080 000257082 000257083000257084 000257086 000257092 000257095 000257224 000257260 000257318 000257320000257322 000257330 000257358 000257364 000257433 000257457 000257468 000257474000257487 000257488 000257490 000257491 000257492 000257530 000257531 000257540000257541 000257560 000257561 000257562 000257563 000257564 000257565 000257566000257587 000257588 000257590 000257592 000257594 000257595 000257601 000257604000257605 000257606 000257630 000257632 000257635 000257636 000257642 000257644000257682 000257684 000257685 000257687 000257688 000257694 000257697 000257724000257725 000257727 000257733 000257734 000257735 000257737 000257892 000257893000257901 000257912 000257932 000257936 000257937 000257939 000257957 000257958000257960 000257963 000257979 000257986 000257989 000258008 000258012 000258014000258017 000258019 000258039 000258041 000258042 000258045 000258048 000258049000258059 000258060 000258062 000258063 000258107 000258108 000258109 000258113000258114 000258117 000258178 000258197 000258202 000258203 000258204 000258256000258257 000258258 000258270 000258271 000258273 000258274 000258278 000258280000258299 000258301 000258302 000258303 000258306 000258307 000258332 000258336000258359 000258387 000258388 000258391 000258393 000258399 000258426 000258452000258454 000258456 000258477 000258498 000258499 000258537

Table A6 Run list for period LHC16k

000258919 000258920 000258921 000258923 000258931 000258962 000258964 000259086000259099 000259117 000259118 000259162 000259164 000259204 000259261 000259263000259264 000259269 000259270 000259271 000259272 000259273 000259274 000259302000259303 000259305 000259307 000259334 000259339 000259340 000259341 000259342000259378 000259379 000259381 000259382 000259394 000259395 000259396 000259469000259471 000259477 000259649 000259650 000259668 000259697 000259700 000259703000259704 000259705 000259711 000259713 000259750 000259751 000259756 000259788000259789 000259822 000259841 000259842 000259860 000259866 000259867 000259868000259888 000259954 000259961 000259979 000260010 000260011 000260014

Table A7 Run list for period LHC16l

109

000260218 000260240 000260310 000260312 000260313 000260338 000260340 000260351000260354 000260357 000260379 000260411 000260432 000260435 000260437 000260440000260441 000260447 000260471 000260472 000260475 000260476 000260481 000260482000260487 000260490 000260495 000260496 000260497 000260537 000260539 000260540000260541 000260542 000260564 000260586 000260611 000260613 000260614 000260615000260616 000260647

Table A8 Run list for period LHC16m

000260649 000260650 000260657 000260667 000260671 000260672 000260689 000260691000260693 000260695 000260700 000260704 000260710 000260713 000260722 000260723000260727 000260728 000260740 000260741 000260749 000260750 000260751 000260752000260763 000260770 000260777 000260782 000260784 000260786 000260788 000260804000260808 000260809 000260810 000260815 000260913 000260914 000260920 000260934000260935 000260936 000260938 000260960 000260963 000260992 000260993 000261020000261022 000261025 000261026 000261027 000261052 000261055 000261065 000261076000261083 000261088 000261093 000261094 000261095 000261099 000261100

Table A9 Run list for period LHC16n

000262399 000262418 000262419 000262422 000262423 000262424 000262428 000262430000262451 000262487 000262492 000262528 000262532 000262533 000262537 000262563000262567 000262568 000262569 000262570 000262571 000262572 000262574 000262578000262583 000262593 000262594 000262628 000262632 000262635 000262705 000262706000262713 000262717 000262719 000262723 000262725 000262727 000262760 000262768000262776 000262777 000262778 000262841 000262842 000262844 000262847 000262849000262853 000262855 000262858 000263332 000263487 000263490 000263496 000263497000263647 000263652 000263653 000263654 000263657 000263662 000263663 000263682000263689 000263690 000263691 000263737 000263738 000263739 000263741 000263743000263744 000263784 000263785 000263786 000263787 000263790 000263792 000263793000263803 000263810 000263813 000263823 000263824 000263829 000263830 000263861000263863 000263866 000263905 000263916 000263917 000263920 000263923 000263977000263978 000263979 000263981 000263984 000263985 000264033 000264035

Table A10 Run list for period LHC16o

000264076 000264078 000264082 000264085 000264086 000264109 000264110 000264129000264137 000264138 000264139 000264164 000264168 000264188 000264190 000264194000264197 000264198 000264232 000264233 000264235 000264238 000264259 000264260000264261 000264262 000264264 000264265 000264266 000264267 000264273 000264277000264279 000264281 000264305 000264306 000264312 000264336 000264341 000264345000264346 000264347

Table A11 Run list for period LHC16p

Appendix B

Raw-Background Comparison mdashfigures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150

lt 275y250 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 300y275 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 325y300 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

25310times

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B1 Evolution of signal and combinatorial background shapes for 000 lt pT lt 020 GeVc

112 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

lt 275y250 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 300y275 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 325y300 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 375y350 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 400y375 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B2 Evolution of signal and combinatorial background shapes for 020 lt pT lt 040 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 275y250 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5

310times

lt 300y275 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20310times

lt 325y300 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12

310times

lt 400y375 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B3 Evolution of signal and combinatorial background shapes for 040 lt pT lt 060 GeVc

113

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 275y250 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 300y275 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 325y300 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

80310times

lt 375y350 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 400y375 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B4 Evolution of signal and combinatorial background shapes for 060 lt pT lt 080 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 275y250 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8310times

lt 300y275 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 325y300 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 350y325 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

80310times

lt 375y350 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

50

310times

lt 400y375 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B5 Evolution of signal and combinatorial background shapes for 080 lt pT lt 100 GeVc

114 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600 lt 275y250 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 300y275 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 325y300 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 350y325 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60310times

lt 375y350 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

310times

lt 400y375 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B6 Evolution of signal and combinatorial background shapes for 100 lt pT lt 120 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 275y250 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 300y275 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

50310times

lt 325y300 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

310times

lt 350y325 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

310times

lt 375y350 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

40

50310times

lt 400y375 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B7 Evolution of signal and combinatorial background shapes for 120 lt pT lt 160 GeVc

115

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4310times

lt 275y250 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 300y275 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 325y300 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 350y325 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

10

20

30

310times

lt 375y350 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 400y375 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B8 Evolution of signal and combinatorial background shapes for 160 lt pT lt 200 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5310times

lt 275y250 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 300y275 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20

310times

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

20310times

lt 350y325 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

5

10

15

310times

lt 375y350 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

310times

lt 400y375 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B9 Evolution of signal and combinatorial background shapes for 200 lt pT lt 240 GeVc

116 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 275y250 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

310times

lt 300y275 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

12310times

lt 325y300 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

8

310times

lt 375y350 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5

310times

lt 400y375 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B10 Evolution of signal and combinatorial background shapes for 240 lt pT lt 280 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 275y250 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 300y275 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

2

4

6

310times

lt 325y300 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

5

310times

lt 350y325 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 375y350 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3310times

lt 400y375 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B11 Evolution of signal and combinatorial background shapes for 280 lt pT lt 320 GeVc

117

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25310times

lt 275y250 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 300y275 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

4

310times

lt 325y300 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 350y325 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 375y350 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 400y375 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B12 Evolution of signal and combinatorial background shapes for 320 lt pT lt 360 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 275y250 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 300y275 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3310times

lt 325y300 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 350y325 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 375y350 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 400y375 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B13 Evolution of signal and combinatorial background shapes for 360 lt pT lt 400 GeVc

118 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 300y275 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

1

2

3

310times

lt 325y300 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 350y325 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 375y350 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800

lt 400y375 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B14 Evolution of signal and combinatorial background shapes for 400 lt pT lt 450 GeVc

119

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800 lt 275y250 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310times

lt 300y275 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

25

310times

lt 325y300 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310times

lt 350y325 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 375y350 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 400y375 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B15 Evolution of signal and combinatorial background shapes for 450 lt pT lt 500 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 275y250 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 300y275 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

2

310times

lt 325y300 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 350y325 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 375y350 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300 lt 400y375 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B16 Evolution of signal and combinatorial background shapes for 500 lt pT lt 550 GeVc

120 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400 lt 275y250 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 300y275 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

05

1

15

310times

lt 325y300 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 350y325 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800

lt 375y350 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150

200

250

lt 400y375 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B17 Evolution of signal and combinatorial background shapes for 550 lt pT lt 600 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

lt 275y250 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 300y275 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12310times

lt 325y300 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1310times

lt 350y325 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 375y350 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150 lt 400y375 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B18 Evolution of signal and combinatorial background shapes for 600 lt pT lt 650 GeVc

121

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

lt 275y250 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800

lt 300y275 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800 lt 325y300 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600 lt 350y325 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 375y350 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

20

40

60

80

100

120

140

lt 400y375 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B19 Evolution of signal and combinatorial background shapes for 650 lt pT lt 700 GeVc

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400 lt 275y250 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 300y275 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 325y300 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

310times

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 375y350 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150 lt 400y375 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B20 Evolution of signal and combinatorial background shapes for 700 lt pT lt 800 GeVc

122 Appendix B Raw-Background Comparison mdash figures

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

100

200

300

400

500

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 300y275 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

02

04

06

08

1

12

310times

lt 325y300 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

800 lt 350y325 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

200

400

600

lt 375y350 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 05 1 15 2 25 3 35

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ micro

MdN

d

0

50

100

150

200

lt 400y375 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

Comb bkg

raw mass spectrum

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure B21 Evolution of signal and combinatorial background shapes for 800 lt pT lt 1000 GeVc

Appendix C

Hadronic-Cocktail fits mdash figures

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 350y325 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 375y350 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 400y375 lt

c lt 02 GeVT

p00 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 02 GeVT

p00 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 020 GeVT

p000 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C1 Hadronic cocktail fits for 000 lt pT lt 020 GeVc

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 350y325 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 040 GeVT

p020 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 375y350 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 040 GeVT

p020 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 400y375 lt

c lt 04 GeVT

p02 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 040 GeVT

p020 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 04 GeVT

p02 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 040 GeVT

p020 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C2 Hadronic cocktail fits for 020 lt pT lt 040 GeVc

124 Appendix C Hadronic-Cocktail fits mdash figures

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 350y325 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 375y350 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 400y375 lt

c lt 06 GeVT

p04 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 060 GeVT

p040 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 06 GeVT

p04 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 060 GeVT

p040 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C3 Hadronic cocktail fits for 040 lt pT lt 060 GeVc

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

Not available fit in300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

12

14

310times

lt 350y325 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 080 GeVT

p060 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 375y350 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 080 GeVT

p060 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

25

310times

lt 400y375 lt

c lt 08 GeVT

p06 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 080 GeVT

p060 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 08 GeVT

p06 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 080 GeVT

p060 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 375 lt y lt 400

Figure C4 Hadronic cocktail fits for 060 lt pT lt 080 GeVc

125

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 325y300 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

25

310times

lt 350y325 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

50

310times

lt 375y350 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 400y375 lt

c lt 10 GeVT

p08 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p080 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 10 GeVT

p08 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 100 GeVT

p080 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 375 lt y lt 400

Figure C5 Hadronic cocktail fits for 080 lt pT lt 100 GeVc

Not available fit in250 lt y lt 275

Not available fit in275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

12

14

310times

lt 325y300 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 350y325 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 375y350 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 400y375 lt

c lt 12 GeVT

p10 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 120 GeVT

p100 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 12 GeVT

p10 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 120 GeVT

p100 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 375 lt y lt 400

Figure C6 Hadronic cocktail fits for 100 lt pT lt 120 GeVc

126 Appendix C Hadronic-Cocktail fits mdash figures

Not available fit in250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

12

310times

lt 300y275 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 325y300 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

50

310times

lt 350y325 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

50

310times

lt 375y350 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

40

310times

lt 400y375 lt

c lt 16 GeVT

p12 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 160 GeVT

p120 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 16 GeVT

p12 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 160 GeVT

p120 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 375 lt y lt 400

Figure C7 Hadronic cocktail fits for 120 lt pT lt 160 GeVc

Not available fit in250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 300y275 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 325y300 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30

310times

lt 350y325 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

10

20

30310times

lt 375y350 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

310times

lt 400y375 lt

c lt 20 GeVT

p16 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 200 GeVT

p160 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 20 GeVT

p16 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 200 GeVT

p160 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 375 lt y lt 400

Figure C8 Hadronic cocktail fits for 160 lt pT lt 200 GeVc

127

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 275y250 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 300y275 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

20

310times

lt 325y300 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 350y325 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

5

10

15

310times

lt 375y350 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 400y375 lt

c lt 24 GeVT

p20 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 240 GeVT

p200 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 24 GeVT

p20 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 240 GeVT

p200 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C9 Hadronic cocktail fits for 200 lt pT lt 240 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 275y250 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 300y275 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 325y300 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

10

310times

lt 350y325 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

8

310times

lt 375y350 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

5

310times

lt 400y375 lt

c lt 28 GeVT

p24 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 280 GeVT

p240 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 28 GeVT

p24 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 280 GeVT

p240 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C10 Hadronic cocktail fits for 240 lt pT lt 280 GeVc

128 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

310times

lt 275y250 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 300y275 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

2

4

6

310times

lt 325y300 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

5

310times

lt 350y325 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 375y350 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

310times

lt 400y375 lt

c lt 32 GeVT

p28 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 320 GeVT

p280 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 32 GeVT

p28 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 320 GeVT

p280 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C11 Hadronic cocktail fits for 280 lt pT lt 320 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 275y250 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 300y275 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

4

310times

lt 325y300 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

1

2

3

310times

lt 350y325 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 375y350 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 400y375 lt

c lt 36 GeVT

p32 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 360 GeVT

p320 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 36 GeVT

p32 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 360 GeVT

p320 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C12 Hadronic cocktail fits for 320 lt pT lt 360 GeVc

129

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 275y250 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 300y275 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

25

310times

lt 325y300 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp lt 325y300 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 350y325 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 375y350 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

310times

lt 400y375 lt

c lt 40 GeVT

p36 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 400 GeVT

p360 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 40 GeVT

p36 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 400 GeVT

p360 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C13 Hadronic cocktail fits for 360 lt pT lt 400 GeVc

130 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times

lt 275y250 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

2

310times

lt 300y275 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp lt 300y275 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times lt 325y300 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

05

1

15

310times lt 350y325 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

12

310times

lt 375y350 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

800

lt 400y375 lt

c lt 45 GeVT

p40 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 450 GeVT

p400 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 45 GeVT

p40 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 450 GeVT

p400 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C14 Hadronic cocktail fits for 400 lt pT lt 450 GeVc

131

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

800

lt 275y250 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

12

14310times lt 300y275 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1

310times

lt 325y300 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

02

04

06

08

1310times

lt 350y325 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 375y350 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

500

lt 400y375 lt

c lt 50 GeVT

p45 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 500 GeVT

p450 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 50 GeVT

p45 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 500 GeVT

p450 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C15 Hadronic cocktail fits for 450 lt pT lt 500 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 275y250 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

800

lt 300y275 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 325y300 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 350y325 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 375y350 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 400y375 lt

c lt 55 GeVT

p50 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 550 GeVT

p500 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 55 GeVT

p50 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 550 GeVT

p500 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C16 Hadronic cocktail fits for 500 lt pT lt 550 GeVc

132 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 275y250 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

200

400

600

lt 300y275 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

500

lt 325y300 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 350y325 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 375y350 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 400y375 lt

c lt 60 GeVT

p55 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 600 GeVT

p550 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 60 GeVT

p55 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 600 GeVT

p550 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C17 Hadronic cocktail fits for 550 lt pT lt 600 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300 lt 275y250 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

400

lt 300y275 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 325y300 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 350y325 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 375y350 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 400y375 lt

c lt 65 GeVT

p60 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 650 GeVT

p600 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 65 GeVT

p60 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 650 GeVT

p600 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C18 Hadronic cocktail fits for 600 lt pT lt 650 GeVc

133

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200 lt 275y250 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 300y275 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 325y300 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 350y325 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 375y350 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

20

40

60

80

100

lt 400y375 lt

c lt 70 GeVT

p65 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 700 GeVT

p650 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 70 GeVT

p65 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 700 GeVT

p650 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C19 Hadronic cocktail fits for 650 lt pT lt 700 GeVc

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 275y250 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 300y275 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 325y300 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 350y325 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 375y350 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 400y375 lt

c lt 80 GeVT

p70 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 800 GeVT

p700 lt = 13 TeVsALICE pp

lt 400y375 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 400y375 lt

c lt 80 GeVT

p70 lt

= 13 TeVsALICE pp

lt 400y375 lt

c lt 800 GeVT

p700 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(f) 375 lt y lt 400

Figure C20 Hadronic cocktail fits for 700 lt pT lt 800 GeVc

134 Appendix C Hadronic-Cocktail fits mdash figures

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

250

lt 275y250 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 275y250 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 275y250 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(a) 250 lt y lt 275

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 300y275 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 300y275 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 300y275 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 300y275 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(b) 275 lt y lt 300

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

100

200

300

lt 325y300 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 325y300 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 325y300 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 325y300 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(c) 300 lt y lt 325

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

200

lt 350y325 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 350y325 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 350y325 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 350y325 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(d) 325 lt y lt 350

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

]2 c [d

imuo

ns p

er 2

5 M

eV

- micro+ microM

dNd

0

50

100

150

lt 375y350 lt

c lt 100 GeVT

p80 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 1000 GeVT

p800 lt = 13 TeVsALICE pp

lt 375y350 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

]2c [GeV-micro+microM0 02 04 06 08 1 12 14

Dat

aM

C

081

12

lt 375y350 lt

c lt 100 GeVT

p80 lt

= 13 TeVsALICE pp

lt 375y350 lt

c lt 1000 GeVT

p800 lt

= 13 TeVsALICE pp

B TeyssierWork Thesis

(e) 350 lt y lt 375Not available fit in

375 lt y lt 400

Figure C21 Hadronic cocktail fits for 800 lt pT lt 1000 GeVc

Bibliography

[1] Michael E Peskin and Daniel V Schroeder An Introduction to Quantum FieldTheory Addison-Wesley 3 edition 1951 (Cited pages 1 et 7)

[2] C A Baker D D Doyle P Geltenbort and others Improved Experimental Limiton the Electric Dipole Moment of the Neutron Phys Rev Lett 97(13)131801September 2006 [link] (Cited page 4)

[3] SM Barr A review of CP violation in atoms International Journal of ModernPhysics A 08(02)209ndash236 January 1993 [link] (Cited page 4)

[4] C Patrignani K Agashe G Aielli and others Review of Particle PhysicsChinPhys C40100001 October 2016 [link] (Cited pages 4 5 7 54 56 58et 105)

[5] E Eichten K Gottfried T Kinoshita and others Charmonium The model PhysRev D 17(11)3090ndash3117 June 1978 [link] (Cited page 6)

[6] Gerardrsquot Hooft Symmetry Breaking Through Bell-Jackiw Anomalies PhysRevLett378ndash11 1976 (Cited page 10)

[7] S P Klevansky The Nambu-Jona-Lasinio model of quantum chromodynamics RevMod Phys 64649ndash708 1992 (Cited pages 10 et 12)

[8] P Costa C A de Sousa M C Ruivo and others The QCD critical end pointin the SU(3) NambundashJona-Lasinio model Physics Letters B 647(5)431ndash435 April2007 [link] (Cited page 10)

[9] J Stachel and G R Young Relativistic Heavy ION Physics at CERN and BNLAnnu Rev Nucl Part Sci 42(1)537ndash597 December 1992 [link] (Cited page 13)

[10] H R Schmidt and J Schukraft The physics of ultra-relativistic heavy-ion collisionsJ Phys G Nucl Part Phys 19(11)1705 1993 [link] (Cited page 13)

[11] RHIC Physics of the Relativistic Heavy Ion Collider 2017 [httpswwwbnlgovrhicphysicsasp] (Cited page 13)

[12] CERN Heavy ions and quark-gluon plasma [httpshomecernaboutphysicsheavy-ions-and-quark-gluon-plasma] (Cited page 13)

[13] ALICE Collaboration φ-meson production at forward rapidity in p-Pb collisionsat radicsNN = 502 TeV and in pp collisions at

radics = 276 TeV Physics Letters B

768203ndash217 May 2017 [link] (Cited pages 14 15 et 26)

[14] Michael L Miller Klaus Reygers Stephen J Sanders and others Glauber Model-ing in High-Energy Nuclear Collisions Annu Rev Nucl Part Sci 57(1)205ndash243October 2007 [link] (Cited page 14)