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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