Performance Evaluation for Open Charm and Beauty
Measurement at LHC ALICE
PID capability from λ and Ks0 meas
urement at LHC ALICE
筑波大学数理物質科学研究科Kengo Watanabe for the ALICE Collaboration
ALICE Detector Over View
TRDTOFHMPID
PMD
PHOS TPC
Muon Spectrometer
ITS
• To provide constrains on parton energy loss
at the very early stage of the collisions
(time-scale ~ 1/mQ < τQGP ~ 10 fm at LHC)
• c,b have long lifetime (> τQGP) and can probe the bulk,
strongly interacting phase
study of final state effects• Elliptic flow
Open Charm and Open Beauty Measurement
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ǙDZÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB
( )( )RPv Ψ−= ϕ2cos2
V2 provides information on the opacity of the medium
Heavy flavour measurements in ALICE
Weak decaying charm and beauty
D+ m ~ 1869 MeV, cτ ~ 312 μmD0 m ~ 1865 MeV, cτ ~ 123 μmDs
+ m ~ 1968 MeV, cτ ~ 147 μm
B+ m ~ 5279 MeV, cτ ~ 501 μmB0 m ~ 5279 MeV, cτ ~ 460 μmBs
0 m ~ 5370 MeV, cτ ~ 438 μmBc
+ m ~ 6400 MeV, cτ ~ 100~200 μm
Primary vertex
Decay vertex
Heavy flavour weak decay track is displaced from primary vertex by ~ few 100 μm
Decay vertex will be observed with help of the ITS
Inner Tracking System contain 6 silicon layerssilicon pixel detector reconstruct secondary vertex
Secondary tracks will be reconstructedwith help of the ITS,TPC,TRD and TOF
Outline• Simulation Data
0.9GeV minimum bias event
PYTHIA, ALICE GEANT• Reconstruction
all simulation data were reconstructed
-> track, vertex ,signal in each detector
• PID (ITS,TPC,TOF)
• λ and Ks0 measurements
invaliant mass, S/N,S*S/N
PID cut, Pt dependence ALICE detector performance
Particle Identification in ALICE 1
ITS
TPC
All signal cut (track length = 0) cut (combined bands)
π
π
K
p
e
Kp
Particle Identification in ALICE 2
Before cut After cut
π
K
p
• Input data
0.9 TeV pp minimum bias.
1 M events reconstructed data (ALICE official data)
• Electron data
3000 events (NO TRD PID)
TRD show other particle contamination
in TPC electron band
PID Summary
Open charm and Open Beauty production are difficult for my data
ALICE performance using Ks0 and λ
λ & Ks0 invaliant mass
(ITS && TPC) or TOF ITS or TPC or TOF ITS or TPC or TOFmix
λ->p+π (unlike pair)
Ks0->π+π (unlike pair)
S/N
(ITS && TPC) or TOF ITS or TPC or TOF ITS or TPC or TOFmix
S/N=1.74 1.60 1.59
1.19 1.15 1.15
background
signal
λ
Ks0
S*S/N = 260364
S=226385S/N=
S*S/N=15235.9
S/N=S=9533
S*S/N=260288
S/N=S=226329
S*S/N=15232.5
S/N=S=9515
S*S/N=149771
S/N=S=126290
S*S/N=11665.7
S=6714
Pt cut
0<Pt<0.25 0.25<Pt<0.5 0.5<Pt<0.75 0.75<Pt<1.0
1.0<Pt<1.5 1.5<Pt<2.0 2.0<Pt<2.5 2.5<Pt<3.0
λ
Pt dependence of S/N
(ITS && TPC) or TOF
Pt (GeV/c)Pt (GeV/c)
ITS or TPC or TOF
ITS or TPC or TOFmix
S/N S/N
TOF
ITS,TPC
Ks0λ
TOFITS,TPC
S/Nits ≒ S/Ntpc
PID capability of ITS and TPCis certain
• Particle identification of ALICE central detector (ITS,TPC,TOF) using simulation data
• S/N, S*S/N from λ and Ks0 mass spectrum
• S/N show good PID capability of ITS and TPC• S*S/N show miss ID particle can be ignored
Summary
ALICE will be able to Identified rare particle, D,B,J/Ψ,Υwith help of vertex detector and PID detector
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