Outline  Charm and Beauty at the LHC  Heavy-flavour program in ALICE  Measurements in preparation  Examples of expected performance  Conclusions Heavy Flavours in ALICE Giuseppe E Bruno Università di Bari and INFN – Italy for the ALICE collaboration

E. Bruno2 LHC  Running conditions:  + other ions (Sn, Kr, O) & energies (e.g.: 5.5 TeV) *L max (ALICE) = ** L int (ALICE) ~ 0.5 nb -1 /year Collision system √s NN (TeV)L 0 (cm -2 s - 1 ) Run time (s/year)  geom (b) pp * PbPb **7.7 pPb ArAr

E. Bruno3 Heavy LHC  cc and bb rates NLO predictions (ALICE baseline) * M.Mangano beauty charm 115 / / / 0.2 Pb-Pb 5.5 TeV (5% cent) 0.16 / / / 0.5 pp 14 TeV shadowing system NN x-sect (mb) total multiplicity factor ~2 uncertainty

E. Bruno4  Probe unexplored small-x region with HQs at low p t and/or forward y  Charm measurements at low-p t or forward y  Window on high-density PDFs phenomenology: gluon saturation / recombination effects / CGC The charm of small-x gluons Cartoon charm beauty D mesons p t  0, y=0 J/  p t  0, y  4 x~10 -4 x~10 -6  s=14 TeV

E. Bruno5 Charm & beauty as probes  calculable in pQCD; calibration measurement from pp rather solid ground  caveat: modification of initial state from pp to AA shadowing ~ 30 % saturation?  pA reference fundamental!  produced essentially in initial impact probes of high density phase  no extra production at hadronization probes of fragmentation  e.g.: independent string fragmentation vs recombination

E. Bruno6 Probing the medium  quenching vs colour charge heavy flavour from quark (C R = 4/3) jets light flavour from (p T -dep) mix of quark and gluon (C R = 3) jets  quenching vs mass heavy flavour predicted to suffer less energy loss  gluonstrahlung  collisional loss beauty vs charm

E. Bruno7 Quarkonia at LHC: (cc) & (bb)  J/ suppression & regeneration?   c,  ’ suppression (J/ T D ~ T c )? SPS RHIC LHC 30 enhanced suppression enhanced regeneration T LHC >> J/  T D   melts only at LHC  ’ T D ~ J/ T D  Small  regeneration  ’ can unravel J/  suppression VS regeneration

E. Bruno8 Physics at LHC - Philippe Pillot MUON Spectrometer Acceptance: η<|0.9| (di)electrons: J/ ,  ’, ,  ’,  ’’ open charm & beauty hadrons: D ±, D 0, … Acceptance: -4<η<-2.5 (di)muons: J/ ,  ’, ,  ’,  ’’ open charm & beauty electron-muon coincidences: open charm & beauty 8 TOF PID TOF PID TRD Electron ID TRD Electron ID ITS Vertexing, Low p t tracking ITS Vertexing, Low p t tracking TPC Tracking, dE/dx TPC Tracking, dE/dx The ALICE detector

9 9 ALICE Status Complete: ITS, TPC, TOF, HMPID, FMD, T0, V0, ZDC, Muon arm, Acorde Partial installation: 1/5 PHOS 4/18 TRD 9/48 PMD 0/6 EMCAL ~ 40% DAQ/HLT ALICE Detector Installation mid 2008 Installation targets met by mid 2008

E. Bruno10 Hadronic charm TPC (tracking) TOF (K/  id) ITS (vertexing) K  D 0  K  D +  K  D s  KK  D*  D 0  D 0  K   c   Kp under study D0D0

E. Bruno11 Impact parameter resolution  d 0 = distance of closest approach between track and primary vertex  d 0 resolution mainly provided by the two innermost layers of the ITS (pixels) R=4 and 7 cm, ~10 7 channels pixel size 50425 m BEAM (Z) PIXEL CELL z: 425  m r  : 50  m Two layers: r = 4 cm r = 7 cm Silicon Pixel Detector Impact parameter 1.5 GeV d 0 resolution

E. Bruno12 pair of opposite-charge tracks with large impact parameters good pointing of reconstructed D momentum to the primary vertex D0D0 Charm reconstruction: D 0  K -  + Invariant mass analysis  Two vertexing algorithms with full error-matrix treatment  Large combinatorial background (dN ch /dy=6000 in Pb-Pb simul.)  Main selection: displaced-vertex selection systempppPbPbPb  s (TeV) trigMB CC N evt time (months)811 p t min (GeV/c)0.5 1 E stat (%)327 E syst (%)141617

E. Bruno13 Beauty from single electrons ITS (vertexing) TPC (tracking + e/  id) TRD (e/  id) e Primary Vertex B e X d0d0 rec. track B  e+X

E. Bruno14  Expected ALICE performance (1 month Pb-Pb) e ± identification from TRD and dE/dx in TPC impact parameter from ITS S/(S+B) S per 10 7 central Pb-Pb events Beauty in the barrel: displaced e’s Error composition stat error stat  syst error 11% from overall normalization not included

E. Bruno15 Beauty from displaced J/ TPC (tracking + e/  id) TRD (e/  id) ITS (vertexing) e + e  y x B e+e+ e-e- J X B  J/+X e-e+e-e+

E. Bruno16 Beauty in the barrel: Events/10 MeV 10 9 pp events m(e +,e-) [GeV] Events/10 MeV tot J/ bkg displaced J/e - e +  Analysis based on a simultaneous fit of 1.the invariant mass spectrum

E. Bruno17 Beauty in the barrel: displaced J/e - e +  Analysis based on a simultaneous fit of 1.the invariant mass spectrum 2.an “impact parameter” to separate prompt from detached J/e.g. pseudo- proper decay time (à la CDF) D.Acosta et al Phys. Rev. D 71 (2005)  This measurements can allow a determination of the d bb /dp t cross-section down to p t ≈0 p T > x [m] Entries/100m <p T <3 Gev x [m] Entries/100m p T >5 Gev x [m] Entries/100m CDF tot J/ J/ from B bkg sum ALICE 10 9 pp events

E. Bruno18 Expected performance on D, B R AA m b = 4.8 GeV D 0  K    B  e + X 1 year at nominal luminosity (10 7 central Pb-Pb events, 10 9 pp events)  should clarify the heavy flavour quenching mechanism mass dependence colour charge dependence

E. Bruno19 ITS (vertexing) TPC (tracking) TRD (e/  id) MUON (tracking,id)  e e  Quarkonia  Measured both in the di-electron (midrapidity, TRD) and di-muon (forward rapidity, MUON) channel

20 Particle Charmonia  +  - Charmonia e + e - Bottonia  +  - Bottonia e + e - Bkg- subtracted mass plot acc.  -4 <  < -2.5|  | < <  < -2.5|  | < 0.9 M res.65 MeV35 MeV90 MeV J/  150,  ’ 7 J/  245  30,  ’ 12,  ’’ 8  21,  ’ 8 perf. , ?  ’ , ??  ’ ,  ’, ?  ’’ , ?  ’, no  ’’ ptpt J/  0-20 GeV J/  0-10 GeV  0-8 GeV-- Quarkonia Performance Bkg input: dN ch /dy=4000 in central Pb-Pb. for 1 month

E. Bruno21 Many other channels charm: exclusive hadronic channels D 0  K  (tested in pp & PbPb) D +  K  (tested in pp & PbPb) D ± s  KK  (under study) D*  D 0  (under study) D 0  K  (under study)  c  pK  (under study) charm & bottom: semi-inclusive leptonic channels c  l + X (à la CDF & D0) b  l + X (à la CDF & D0) b  J/  + X (à la CDF & D0) bbbar  J/  + l (under study) bbbar  3  (should work in pp) bbbar  l + l -,l - l + (Bchain & BBdiff) bbbar  l - l -,l + l + (Bchain & B osc.)

E. Bruno22 Summary  LHC: heavy quarks and quarkonia factory  Heavy quarks as probes of QCD in extreme conditions low p t : probe small-x structure of p and nucleus intermediate p t : probe medium thermalisation (reco/flow) high p t : probe medium density via energy loss  Charmonia & bottomonia as probes of QCD phase transition  ALICE in excellent position: dedicated detectors promising performance for all key measurements

E. Bruno23 Thank you First interaction in ALICE: (beam – pixel collisions)