forward experiments at lhc: how lhc can contribute to cosmic ray physics alessia tricomi university...
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Forward Experiments at LHC:how LHC can contribute to Cosmic Ray
PhysicsAlessia Tricomi
University and INFN Catania
EDS’09: 13th International Conference on Elastic & Diffractive
ScatteringCERN, 29 June – 3 July 2009
Physics Motivations
Forward Experiments
Physics performances
Ultra High Energy Cosmic Rays
Experimental observations: at E>100 TeV only EAS(shower of secondary particles)• lateral distribution• longitudinal distribution• particle type• arrival direction
Extensive Air Showers
Astrophysical parameters:(primary particles)• spectrum• composition• source distribution• origin and propagation
Air shower development (particle
interaction in the atmosphere)
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
GZK cutoff: 1020 eV
GZK cutoff would limit energy to 1020eV (for
protons, due to Cosmic Microwave Background
pg(2.7K)DNp
The Cosmic Ray Spectra
Based on data presented at the 30th ICRCMerida (Mexico)Figure prepared by Y. Tokanatsu
super GZK events?!?
Different results between different
experiments
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
The Cosmic Ray SpectraDifference in the energy scale between different
experiments???
Berezinsky 2007
AGASA SystematicsTotal ±18%Hadron interaction (QGSJET, SIBYLL) ~10% (Takeda et al., 2003)
AGASAx 0.9HiRes x 1.2Yakutsk
x 0.75Auger x 1.2
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
HECR composition
Xm
ax(g
/cm
2)
IRON
The depth of the maximum of the
shower Xmax in the
atmosphere depends on energy
and type of the primary particle.
Different hadronic
interaction models give
different answers about
the composition of HECR.
IRON
PROTON
Unger, ECRS 2008LHC
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
HECR composition
Auger Xmax measurements
favors heavier composition as the energy increases
Anisotropy would favor proton
primaries (AGN correlation)
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Modelling Cosmic Rays at LHC
Astrophysical parameters - source type - source distribution - source spectrum - source composition - propagation
LHC
Forward Physics - cross section - particle spectra (E, PT, q, h, XF)
Nuclear Interaction - calibration with data of Monte Carlo used in Cosmic Ray Physics
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Development of atmospheric showers
LHC
Tevatron
A 100 PeV fixed-target interaction with air has the cm energy of a pp collision at the LHC
AUGER
Cosmic ray spectrum
Determination of E and mass of cosmic rays depends on description of primary UHE QCD (p+N,O Fe+N,O) interactionHadronic MC’s need tuning with dataThe dominant contribution to the energy flux is in the very forward region ( 0)In this forward region the highest energy available measurements of p0 cross section done by UA7 (E=1014 eV, y= 5÷7)
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Use LHC (firstly proposed by LHCf) √s = 14 TeV Elab=1017 eV to calibrate MCs
But…
Charged particles
Neutral particles
Beam pipe
General purpose detectors (ATLAS, CMS,…) cover only the central region
Special detectors to access forward particles are necessaryAlessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
How to access Very Forward Physics at LHC?
Charged particles
Neutral particles
Beam pipe
Surrounding the beam pipe with detectorsSimple way, but still miss very very forward particlesAlessia Tricomi
University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Neutral particles
Beam pipe
Charged particles
Install detectors inside the beam pipeChallenging but ideal for charged particle(TOTEM)
How to access Very Forward Physics at LHC?
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Y shape chamber enables us whole neutral measurementsZero Degree Calorimeters
Charged particles
Neutral particles Beam pipe
How to access Very Forward Physics at LHC?
LHCf
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
E leading hadron
E0
Elasticity / inelasticity Forward spectra Cross section
EM shower
Key Measurements at LHC
Neutrals in ZDCs / LHCf: neutrons, mesons (p0,K0
s g )
TOTEMATLAS Fwd (ALFA)
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Pseudo rapidity coverage at LHC
pseudorapidity: h = - ln (tanq/2)
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Particle production at LHC over ≅±Dh 10All phase space covered thanks to dedicated forward detectors!
LHC experiments
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
IP1: ATLAS forward detector
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
LUCID (Cerenkov Tubes, 17m): Cerenkov hits over 5.4 < |η| < 6.1
ZDC (W/Q-fiber calo, 140m): Neutral calorimetry over |η| > 8.3
ALPHA (Sci-Fi RPs): Proton taggers at ± 240 m
FP220,FP420 (Si trackers, timing): Proton tracking at ±220, 420 m
IP1: LHCf detector
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
UHECR-oriented experiment (~30 Japan-European Collaborators)Installed at ±140 m on both side of IP1 in TAN region
Double ARM detector:ARM1: Sci/W + 4 XY Sci Fiber LayersARM2: Sci/W + 4 XY Si m-strip Layers
IP2-IP8: ALICE/LHCb forward detectors
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
ZDCs also at ±7m, ±100 m
Good capabilities for heavy Q, QQ, gauge
boson measurements(low x-PDFs)
IP5: CMS forward+TOTEM detectors
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
IP5: CMS forward+TOTEM detectors
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
TOTEM-T1,T2 (CSC/GEM telescopes):Tracking over 3.1 < |η| < 4.7, 5.3 < |η| < 6.7
CASTOR (W/Q-fiber calo): Calorimetry over 5.1 < |η| < 6.6
ZDC (W/Q-fiber calo): Neutral calorimetry for |η| > 8.3
TOTEM (Si Roman Pots): Proton taggers at ±147, ±220 m
FP420 (Si trackers, timing):Proton tracking at ±420 m
TOTEM: p-p total cross section
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
(E710/811–CDF 2.6σ disagreement)
~ l n 2 s
Extrapolations vary by σ(LHC) = 90-130 mb
€
−20+10%
TOTEM goal: ≅1% precisionspecial run/optics: various β*, low lumi
ZDC: Zero Degree Calorimeters
ALICE, ATLAS & CMS ZDC (complemented by CASTOR)– Total energy flow, wide aperture, high energy
resolution for hadrons, (proton measurement only by ALICE ZDC)
» enhance acceptance of central detectors for diffractive Physics
» kinematics and production spectra of forward particles
Characterize Event:» Count spectator neutrons» Measure centrality (magnitude and direction of impact parameter)
pp Physics
ATLAS ZDC ATLAS ZDC
HI
Physics
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Zero Degree Calorimeters: LHCfLHCf: same h coverage as other ZDCs but
fully dedicated experiment to HECR Physics– Double ARM calorimeters with imaging and PID
capabilities– Excellent energy resolution(<5%) for g and p0, p0 mass
resolution (< 5%) and Spatial resolution (40-200 mm)– Good neutron energy resolution (<30%)Energy Resolution:
SPS electron data
Dm/m < 4%1.04 107 events≅20 min @L=1029cm-2s-1
Spatial Resolution:SPS-200 GeV electrons
Very important toolto calibrate energy scale
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Nu
mb
er
of
even
t
σx=40 mm
x-pos[mm]
Spatial Resolution:SPS-200 GeV electrons
LHCf : Monte Carlo discrimination
106 generated LHC interactions 1 Minute exposure@1029 cm-2s-1 luminosity Discrimination between various models is feasible
Quantitative discrimination with the help of a properly defined c2 discriminating variable based on the spectrum shape (see TDR for details)
5% Energy resolution
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
LHCf: model dependence of neutron energy distribution
Original n energy 30% energy resolution
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
New Models
Drescher, Physical Review D77, 056003 (2008)
PICCOEPOS
Neutron p0
Proton29
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
MC model tuning: pp @ √s=14 TeV
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Dominated by Soft QCD: underlying events, multiparton interactions, fragmentations
MC Model tuning: p+A @ √s= 8.8 TeV
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
MC Model tuning: A+A @ √s=5.5 TeV
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Conclusions and plansCompilation of EAS data is affected by the uncertanties of hadron interaction models.LHC fwd experiments will provide crucial data of hadron interaction for CR study covering the whole phase space
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Several detectors already installedLHCf ready for data taking already during LHC commissioningWe need only to wait LHC restart!
Hoping to answer all our questions and to help EAS experiments to interpret their data
Aknowledgement
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Thanks to ALICE, ATLAS, CMS, LHCb, LHCf, TOTEM Collaborations for useful materialIn particular, I wish to thankO. Adriani, K. Eggert, D. D’Enterria, P. Grafstrom, M. Grothe, S. White
Back-up slides
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Cosmic Ray Composition
QGSJET01
SIBYLL 2.1
Kascade Results
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
CMS CASTOR & ZDC calorimeters
• extends calorimetric coverage of CMS to 5.2 < η < 6.6
• signal collection through Čerenkov photons transmitted to PMTs through aircore lightguides
• W absorber & quartz plates sandwich,
• electromagnetic and hadronic sections
• 16 seg. in φ, 14 seg in z, none in η
• 140 m from interaction point in TAN absorber
• Tungsten/quartz Čerenkov calorimeter with separate e.m. and had. Sections
• Acceptance for neutrals (γ, π0, n) from η > 8.1, 100% for η > 8.4
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
TOTEM T1 & T2 tracking detectors
3m
Test Beam
Cathode Strip Chambers (CSC) Mounted in front of HadronForward calorimeter of CMS 3.1 < | < 4.7 5 planes with 3 coordinates/plane 6 trapezoidal CSC detectors/plane Resolution ~ 0.8mm
Gas Electron Multiplier (GEM) Mounted in front of CASTOR 5.3 < | < 6.5 10 planes formed by 20 GEM semi-circular modules Radial position from strips, h, from pads Resolution strip~70mm
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Detector #1
16 scintillator layers (3 mm
thick)
Trigger and energy profile measurements
Absorber22 tungsten layers 7mm – 14 mm thick
(W: X0 = 3.5mm, RM = 9mm)
4 pairs of scintillating fiber layers for tracking purpose (6, 10, 32, 38 r.l.)
Energy
Impact point (h)
2 towers 24 cm long stacked vertically with 5 mm gap
Lower: 2 cm x 2 cm area
Upper: 4 cm x 4 cm area
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Detector # 2
4 pairs of silicon microstrip layers (6, 12, 30, 42 r.l.) for tracking purpose (X and Y directions)
16 scintillator layers (3 mm
thick)
Trigger and energy profile measurements
Absorber22 tungsten layers 7mm – 14 mm thick (2-4 r.l.)(W: X0 = 3.5mm, RM = 9mm)
2 towers 24 cm long stacked on their edges and offset from one another
Lower: 2.5 cm x 2.5 cm
Upper: 3.2 cm x 3.2 cm
Energy
Impact point (h)
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Detec
table
eve
nts
140
Beam crossing angle
LHCf: acceptance on PTg-Eg plane
A vertical beam crossing angle > 0 increases the acceptance of LHCf
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Position Resolution X Side
0
20
40
60
80
100
120
0 50 100 150 200 250
Energy (GeV)
Re
so
luti
on
(m
icro
ns
)
Data
ARM2 Position ResolutionN
um
ber
of
even
tN
um
ber
of
even
t
σx=40 mm
x-pos[mm]
y-pos[mm]
200 GeV electrons
σy=64 mm
Position Resolution Y Side
0
20
40
60
80
100
120
140
160
0 50 100 150 200 250
Energy (GeV)
Re
so
luti
on
(m
icro
ns
)Data
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
ARM1 Position resolution
σx[m
m]
σy
[mm
]
Nu
mb
er
of
even
tN
um
ber
of
even
t
x-pos[mm]
y-pos[mm] E[GeV]
E[GeV]
200 GeV electrons
σx=172 mm
σy=159 mm
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
ARM2-Silicon Energy Resolution
DE/E ~ 12%
No correction/calibration applied
ADC
E nergy L inearity with S ilicon S ensors
y = 24,927x - 596,44
R2 = 0,994
0,00E+00
5,00E+02
1,00E+03
1,50E+03
2,00E+03
2,50E+03
3,00E+03
3,50E+03
4,00E+03
4,50E+03
5,00E+03
0 50 100 150 200 250
Energy (GeV)
En
erg
y M
ea
su
red
(a
.u.)
Data
Lineare (Data)
200 GeV electronsSPS beam test data
Only silicon energy resolution ~ 10%!!!!!We can use it as a check for the radiation damage of the scintillators
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Energy Resolution
Monte Carlo
SPS beam test
Energy distribution is corrected for leakagecorrection
Distance from Edge
N P
art
icle
s
MC predicts that the leakage is energy independent!
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
QGSJETII: used modelQGSJET: c2/DOF=107/125DPMJET3: c2/DOF=224/125SYBILL: c2/DOF=816/125
g ray energy spectrum for different positions
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
p0 spectra
QGSJETII ⇔ DPMJET3χ2= 106 (C.L. <10-6) ⇔ SIBYLL χ2= 83 (C.L. <10-6)DPMJET3 ⇔ SIBYLL χ2= 28 (C.L.= 0.024) 107events DOF = 17-2=15
p0 produced at collision can be extracted by using gamma pair eventsPowerful tool to calibrate the energy scale and also to eliminate beam-gas BG
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
p0 reconstruction
9.15 m
g
g350 GeV Proton beam
Carbon target (6 cm)in the slot used for beam monitor Arm1
Not in scale!
>107 proton on target (special setting from the SPS people)Dedicated trigger on both towers of the calorimeter has been used
(MeV)
Prelim
inary!!!! 250 p0 events
triggered (in a quite huge background) and on diskMain problems: low photon energy (≥
20 GeV) Direct protons in the
towers Multi hits in the same
tower
Ex:Dm ~ 8 MeVDm/m ~ 6%Sim:Dm/m ~ 5%
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
p0 rate
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
The LPM effect
Transition curve of a1 TeV photon w/ and w/o LPM to be measured by LHCf
○ w/o LPM■ w/ LPM
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
g rate
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Estimate of the background beam-beam pipe E γ(signal) > 200 GeV, OK background < 1%
beam-gas It depends on the beam condition
background < 1% (under 10-10 Torr) beam halo-beam pipe It has been newly estimated from the beam loss rate
background < 10% (conservative value)
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
‘Analysis’ of Beam Gas events
We got 116 FC triggers in 8.275.034 BPTX: Nt=1162.109 protons/bunch Total # of protons: Np=1.7 x 1016
We try to estimate the gas density r from this rate:Nt=Np* L * s * r
L=effective lenght ~ 100 ms=Cross section ~ 80 mbarn = 80 x 10-31 m2
We find: r = 8.5 x 1012 H/m3 = 4.2 x 1012 H2/m3
From the LHC Project Report #783: r = 1012 H2/m3
From the pressure measurement in April 2008: r ~ 1012 H2/m3
~ CONSISTENT!!!!!!!!!!!!!Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Low-x Physycs and UHECR
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
Reduced dN/dη :Less penetration: lower X (~ -30 g/cm2)
Reduced charm cross sections: Less muons !
Forward QQ in ALICE
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
D. D’Enterria (Trieste May 09)
g*, Z, W in LHCb (2<h<5
Alessia Tricomi University & INFN Catania
Forward Experiments at LHC EDS'09, CERN 29 Jun - 3 July
2009
D. D’Enterria (Trieste May 09)