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Charm and Beauty in ALICEfor
CERN Yellow Report“Hard Probes in Heavy Ion Collisions at LHC”
Conveners:Philippe Crochet
Andrea Dainese
Ermanno Vercellin
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Section Outline
INTRODUCTION
ALICE DETECTOR
MUONS:Quarkonia
D and B mesons
ELECTRONS:Quarkonia
D and B mesons
ELECTRON-MUON COINCIDENCES
HADRONS
PROTON-NUCLEUS
SUMMARY
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Introduction
Motivations for Quarkonia studies at LHCcharmonium study from SPS to RHIC to LHC
stress on s as uniqueness of ALICE @ LHC
Motivations for open c and bthermal charm? parton energy loss?
present experimental picture
uniqueness of ALICE: detectors dedicated to displaced vertices ID, exclusive reconstruction of D mesons down to pT ~ 1 GeV/c
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ALICE Detector
This you know…
Stress on the request for high level reconstruction and PID performances up to dNch/dy = 8000
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Muons: Quarkonia (I)
Acceptance for J/ () (w/o and w/ 1 (2) GeV/c cut on pT)
J/
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Muons: Quarkonia (II)
Mass resolutions: from MUON TDR
Significances (MUON TDR):
J/ ’ ’ ’’
310 12 39 19 12
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Muons: D and B
Strategy for unlike-sign dimuon invariant mass analysis to extract B mesons yield from:
high inv. mass region (6 – 9 GeV/c): B B low inv. mass region (1 – 3 GeV/c): B D B D
Possibility of like-sign dimuon analysis exploiting B mesons oscillations
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Electrons: Quarkonia
Acceptance for J/ () (w/o and w/ 3 GeV/c cut on e pT = effect of TRD L1 trigger)
J/
expected mass resolution for @ B = 0.4T: 100 MeV
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Electrons: B mesons (I)
Short description and results of full simulation feasibility study for B e + X in Pb-Pb
Electron identification in TRD-TPC (pT > 1 GeV/c)
electron contamination: 1/100 in TRD, 1/100 in TPC (dE/dx)
B electron identification:cut on pT : reject low pT backgrounds (conversions, dalitz of light mesons)
cut on impact parameter: reject background from D mesons
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Electrons: B mesons (II)S/(S+B) S per 107 Pb-Pb events
pT > 2 GeV/c, d0 > 180 m: 80000 electrons with S/(S+B) = 90 %
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Electrons: B from displaced J/B J/ e+e-
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e- coincidences
Strategy for detection of DD, BB pairs from coincidences of e in ITS-TPC-TRD and in MUON
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Hadrons: D0 K-+ (I)
Full simulation feasibility study in Pb-Pb and pp
K inv. mass in Pb-Pbsignificance = 37system
(s)Pb-Pb
(5.5 TeV)
pp
(14 TeV)
S for 107 (109) evts 13000 20000
S/B 11 % 50 %
significance for 107 (109) evts
37 84
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Hadrons: D0 K-+ (II)
Pb-Pb
pp
down to ~ 1 GeV/c
down to ~ 0 GeV/c
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pA
Motivations:measure charmonium “normal nuclear absorption”
measure shadowing to “understand” heavy flavours cross-section in Pb-Pb
study parton energy loss in cold nuclear medium
ALICE strongly committed to pA
Outline of pA runs in LHC “schedule”
Performances:under study
expected performance for exclusive D meson reconstruction: close to what achieved in pp, since dNch/dy will not be “much larger” in p-Pb than in pp [it’ll be much closer to that of pp than to that of Pb-Pb]
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Summary
ALICE’s excellent reconstruction and PID performances
will allow to study:
the complete spectrum of heavy quarkonia
D and B mesons in many inclusive channels
D mesons in the exclusive hadronic channel down to pT ~ 1 GeV/c