kavli ipmu, tokyo, nov. 14, 2019 lepton dipole moments and...

Leptondipolemomentsandlight(scalar)darkmatter

aswindowstogobeyondtheStandardModel

AntonioMasieroINFNandUniv.ofPadova

Kavli IPMU,Tokyo,Nov.14,2019

-- hintsofviolationoftheleptonflavoruniversalityinsemileptonicBdecays(??)

• ValueoftheHubbleconstantmeasuredtodayorinferredfromthePlanckresultsontheCMB

5numbers,5indicationsofphysicsbeyondtheStandardModelsofParticlePhysicsandCosmology:NEUTRINOMASSES,DARKMATTER,DARKENERGY,ANTIMATTER andVACUUMENERGY

>0.1%

~68%

~27%

0%

1062 % ??thankstoH.Murayama

Thequestioncanberephrasedinto:IsDMagoodhonestweakly(butnottooweakly)interacting (withtheSMparticles)massive(typicallyO(100GeV))particle,i.e.a“traditional”WIMPpartofanextensionoftheSMaccountingfora(possiblynatural)explanationofthe(incrediblysmall)electroweaksymmetrybreakingscaleMW (ascomparedtothePlanckscaleMPl) andconstitutinganSMUVcut-offattheTeV scale?

OrIsDMunrelatedtotheexistenceofanaturalsolutionofthegaugehierarchyproblem.i)Inthiscase DMcanbepartofanSMextensionatE>>MW (forinstanceE~mutiTeV)andthen,presumably,MDM >O(1TeV)(heavyDM)orii)DMcouldbea(very)lightparticlecouplingveryweaklytotheSMparticlesbeingpartofanewdarksectorofthetheorycommunicatingwiththeSMparticlesonlythroughaspecific“portal”,i.e.oneormoreparticlesbridgingthe“darkworld”with”our”SMworld(inthiscasetheDMsectorisnotpartofalargertheoryextendingtheSM,butitcouldbeaseparatesectorofthetheory)

TheDMdilemma:tobeor nottoberelatedtotheelectroweaksymmetrybreaking?

ProsandconstobeaWIMPDM(I)Pros:• i)theWIMPcoincidenceoremphaticallydubbed“WIMPmiracle”(namely:takeaweaklyinteractingO(100GeV)particleonceinthermalequilibriumandcomputeitsnumberdensitytoday– result:typicallyoneendsupwithnWIMP ~10-8 cm-3 leadingtothecorrectDMamount!;

• ii)suchWIMPDMtypicallyconstitutesaformofCOLDDM(hencecorrectlyaccountingforthemainbulkofobservationsonlargescalestructuresdistribution)

• iii)remarkablyenough,themainSMextensionsenvisagedtocopewith”natural”explanation ofthegaugehierarchypuzzleMW <<MPlentailthepresenceofastableparticle,typicallythelightestofthenewparticles characterizingsuchSMextension,whichisapotentiallygoodWIMPDMcandidate.

ProsandconstobeaWIMPDM(II)Thecons:i) Inspiteofconstitutingthemost“wanted”particlecandidateforDM,no

WIMPsignal(oratleasthint)haseveremergedwithsearchesreachingsensitivitiestoWIMP-nucleicrosssectionsdownto10-10 pb;

ii) Thenegativeresultscomingfromhigh-energyandflavourphysics(inparticularLHC)searchesofnewphysicsparticlesaroundthecorner,i.e.intheO(1TeV)massrange,have(largely)reducedourenthusiasmforaTeV newphysicsdirectlylinkedtoanaturalsolutionoftheMW <<MPlgaugehierarchyproblem.And,asaconsequence,thelightestTeV newphysicsparticlehaslostitsappealas“natural”candidateforDM

iii) Themain“victim”ofthislostconnectionDM– TeV newphysicsisundoubtedlytheLightestSUSYParticle,LSP,typicallythelightestneutralino inSUSYmodelswithRparity

SummarytalkbyAsai andCatenaoftheDMWGattheEUStrategyGranadaSymposium

SummarytalkbyAsai andCatenaoftheDMWGattheEUStrategyGranadaSymposium

MaximPospelov,PhysicsBeyondCollidersatCern:BeyondtheStandardModelWorkingGroupReport

MaximPospelov

New physics Λ energy scale and (g-2)μIf New Physics (NP) at a scale Λ gives the contribution δmμto the muon mass, then such NP leads to a loop contribution to the muon magnetic moment aμ :

Czarnecky and Marciano, 2001; Stockinger 2010

~ O(α/4π) if perturbative contributions to the muon mass

~ O (1) if the muon mass is radiatively induced

If the g-2 discrepancy between exp. and SM expectation is a real fact and if we invoke NP to account for it, then

Λ NP has to be at or below the TeV scale !

Minimal extensionsoftheSMtoaccountforthe(g-2)μ anomaly

AdditionofaSINGLENEWFIELD:i) Theadditionofasinglefermioncannotexplainthisanomaly;(C.Biggio 2008;Freitas,Lykken,Kell,Westhoff 2014;Biggio,Bordone 2014)

ii) Theadditionofasinglescalarcanaccountforthediscrepancyifthenewscalaris:anewHiggsdoublet;(Freitas,Lykken,Kell,Westhoff 2014;Broggio,Chun,Passera,Patel,Vempati 2014;Biggio,Bordone 2014;Cherchiglia,Kneschke,Stockinger,Stockinger-Kim2017)

oneofthetwoleptoquarks:S1/3(3,1,-1/3;Q=-1/3);D7/6(3,2,7/6;Q=5/3,2/3) Chakraverty,D.Choudhuri,Datta 2001;Biggio,Bordone 2014;Queiroz,Shepherd2014;Coluccio Leskow,D’Ambrosio,Crivellin,Muller2017

• iii) onemassivevectorboson:onlypossibilityà abeliangaugeextensions– Z’,darkphoton(Biggio,Bordone,DiLuzio,Ridolfi2016;Davoudiasl,H.-S.Lee,Marciano2014;Altmannshofer,C.-Y.Chen,Dev,Soni 2016;)

• iv)ALPs(ALP-photonphoton+ALPYukawainteractionswithleptons)

One-loopcontribution

Two-loopcontributions

Chen,Davoudiasl,Marciano,Zhang2016

Marciano,Masiero,Paradisi,Passera 2016

Pseudoscalar 1σsolutionbandstotheg-2muonanomalytakingΛ =1TeV

Scalar1σsolutionbandstotheg-2muonanomalytakingΛ =1TeV

Marciano,Masiero,Paradisi,Passera 2016

yaμ

Marciano,Masiero,Paradisi,Passera

DMandg-2aswindowstoNewPhysics

• MinimalextensionsoftheSMtoaccountfortheDM:oneadditionalfieldthatbeingneutralandstablemighthavebeeninthermalequilibriuminteractingwithordinarymatterandtodayhavethecorrectdensitytoaccountfortheDM

• MinimalextensionsoftheSMtoaccountfortheg-2anomaly:onesingleadditionalfield(leptoquark oradditionalHiggsdoubletorALPs)couplingsizeablytoleptonsand/orphotons

• IsitpossibletohavejustonesingleadditionalfieldtoaccountforboththeDMand theg-2anomaly?No,theDMfieldsintheseminimalSMextensionsdecaytooquicklytoordinarymatterparticles.Oneneedsatleasttwonewfields (forinstanceoneadditionalfermionandoneadditionalscalar) Calibbi,Ziegler,Zupan 2018

Calibbi,Ziegler,Zupan 2018

F-Sone-loopcontributiontog-2DMannihilationsintoordinarymatter

ModelswithoutandwithHiggsinsertion

Dark(light)greenregionà totalcontributiontog-2compatibleat1(2)σwiththeexperimentalresult

Calibbi,Ziegler,Zupan 2018

ModelswithoutHiggsinsertion

ModelswithHiggsinsertion

Calibbi,Ziegler,Zupan 2018

Twoleptonic g-2anomalies?Recent(Parkeretal.2018)moreprecisedeterminationofthefinestructureconstant

2.4σ discrepancy(oppositeinsignw.r.t.tothemuoncase)

Asinglescalarsolutiontobothanomalies?Yes,ifthetwo-loopBarr-Zeediagrams

dominateovertheoneloopscalarcontributionstothe(g-2)e

withrelativelylargecouplingstotheelectronandthetwophotonsDavoudiasl andMarciano2018

Combinedexplanationof(g-2)e AND(g-2)μwithalargemuonEDM

• EFTanalysis(Crivellin andHoferichter,May2019)

SimultaneousexplanationpossibleinmodelswithchiralenhancementBut,

veryimportant,oneneedsaDECOUPLINGoftheelectronandmuon

BSMsectorstoavoidtheverystringentlimitonBR(μà e+Ɣ)

SuchdecouplingentailsthatthereisnocorrelationbetweentheEDMsoftheelectronandmuon,i.e.theverystringentboundonde doesnotnecessarilyimplyaverysmalldμ

?

Post– LHCphysics

Lepton(g-2),EDMsandDMaspossibleLIGHTHOUSE

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