Heavy flavours & quarkonia @ LHC motivations selected physics channels quarkonia, B-hadron x-section, « hadronic » charm, heavy flavour quenching Philippe.Crochet@clermont.in2p3.fr

Heavy-flavour x-sections @ LHC c(LHC) = c(RHIC) × 10 b(LHC) = b(RHIC) × 100 W(LHC) = (RHIC) × 10 Z(LHC) = (RHIC) K. Safarik

Dileptons @ LHC world data on total x-section of e+e-  hadrons (PDG06)  (pb) s (GeV) a similar plot is accessible in Pb-Pb @ LHC within a few weeks typical number of reconstructed resonances in min-bias PbPb @ 5.5 TeV (1 month)    J/ (1S) Z0 350·103 700·103 300·103 500·103 25·103 11·103

expected number of measured muons in min-bias PbPb @ 5.5 TeV (1 month) Single leptons @ LHC pp @ 14 TeV charm bottom W± expected number of measured muons in min-bias PbPb @ 5.5 TeV (1 month) charm bottom W± 4·108 4·105 11·103 simulation by Z. Conesa del Valle

A closer look at heavy-quark cross-section charm pp @ 14 TeV bottom (14 TeV) / (5.5 TeV) PbPb @ 5.5 TeV charm thermal production ~ 25% (assumes large medium temperature) NLO predictions for pp @ LHC: a factor ~ 2 uncertainty (14 TeV) / (5.5 TeV) ~ 10%  measuring (c,b) in pp @ 14TeV is top priority hep-ph/0601164, J. Phys. G 32 (2006) 1295, J. Phys. G 35 (2008) 054001

Quarkonia suppression @ LHC quarkonium dissociation temperatures A. Mocsy & P. Petreczky, Phys. Rev. Lett. 99 (2007) 211602 RHIC LHC hard gluon induced quarkonium breakup hep-ph/0311048 whether J/ melts or not @ RHIC it will be strongly either suppressed or regenerated @ LHC use (2S) to unravel J/ sup. vs. reco.  reco. is small: L. Grandchamp et al., PRC 73 (2006) 064906 (1S) melts significantly only at LHC additional suppression by hard gluons relevance of quarkonium ratios vs. pt R. Vogt in J. Phys. G 35 (2008) 054001 PbPb @ 5.5 TeV

Charmonium regeneration @ LHC 1. 2. 3. peculiar centrality dependence predictions strongly depend on cc (re-)dissociation by comovers regeneration  smaller <p2t> note: N(B  J/) / N(direct J/) ~ 20% in 4 4. A. Andronic et al., Phys. Lett. B 652 (2007) 259, J. Phys. G 35 (2008) 054001, A. Capella et al., arXiv:0712.4331 [hep-ph], R. Thews et al., J. Phys. G 35 (2008) 054001

Heavy quark quenching @ LHC: new ratios available isolate mass dep. of E sensitivity disappears at large pt lower sensitivity to qhat RD/h probes color charge dep. of E RB/h probes mass dep. of E N. Armesto et al., Phys. Rev. D 71 (2005) 054027, J. Phys. G 35 (2008) 054001

Heavy quark quenching @ LHC: new reference available heavy quark energy loss: shifts down the (c,b)/W crossing point by ~ 5-7 GeV/c suppresses muon yield by a factor 2-5 for 2 < pt < 20 GeV/c W affected by shadowing only Z. Conesa del Valle et al., Phys. Lett. B 663 (2008) 202, J. Phys. G 35 (2008) 054001

Heavy flavour flow @ LHC resonance interactions increase v2 v2 quantitatively similar at RHIC & LHC H. van Hess et al., Phys. Rev. C 73 (2006) 034913, J. Phys. G 35 (2008) 054001 more details in “Heavy Ion Collisions at the LHC, Last Call for Predictions”, May-June 2007, CERN proceedings: J. Phys. G 35 (2008) 054001

Heavy ions @ LHC CMS ATLAS ALICE

Heavy flavours with ALICE electron-muon coincidences: open charm & bottom ITS, TPC, TRD, ToF (||<0.9) (di-)electrons: J/, ’, , ’,’’, open charm, open bottom, W±,Z0 muon spectrometer (-2.5<<-4) (di-)muons: J/, ’, , ’,’’, open charm, open bottom, W±, Z0 hadrons: D0, D±,…

Heavy flavours with CMS & ATLAS muon spectrometer & silicon tracker in central barrel & end-caps (||<2.5) studies limited to J/, ’, , ’,’’ reconstruction & b-jet tagging J/, ’, , ’,’’, open bottom, Z0

Acceptance for heavy flavour measurements complementarity between the 3 experiments ATLAS & CMS acceptance is large in  & limited to high pt ALICE combines hadrons, electrons, muons & covers low pt & high  ATLAS, CMS & ALICE-electrons/hadrons have inner tracking ATLAS & CMS electron/hadron channels not yet investigated

Selected physics channels Quarkonia B from secondary J/ B from dileptons B from single leptons D0  K Heavy flavour quenching only “published” results

Quarkonia

Expected performances for quarkonia WARNING: different simulation frameworks & different assumptions bkg assumes dN/d = 2500-5000, S & S/S+B: one month min-bias PbPb (CC for ALICE e+e-) ALICE +- ALICE e+e- CMS +- ATLAS +- acceptance -4<<-2.5 ||<0.9 ||<2.4 ||<2.5 charmonia (J/) (MeV) 74 30 35 (w/o bkg) 68 S (×103) 677 120 146 8-216 (pt) S/S+B 413 245 234 52-164 (pt) bottomonia () (MeV) 109 90 68-90 (bkg level) 145 (||<2) S , ’, ’’ 6800,1800,100 900,350,- 20300,5900,3500 10000-15000 S/S+B , ’, ’’ 67,30,21 21,8 36,-,- 45-46 J/, : first detailed studies within one month ’: difficult (small S/B), ’, ’’: need 2-3 runs From A. Dainese @ HP2006, updated according to ALICE: J. Phys. G 32 (2006) 1295, W. Sommer et al. @ QM2006, CMS: J. Phys. G 34 (2007) 2307, CMS/note-2006/089, ATLAS: L. Rosselet @ HEP2007

Normalization for suppression studies normalisation pros. cons. open heavy flavours most natural quenching, thermal (charm) production excited states sensitivity to medium size & temperature hard partons, exp. reach (e.g. ’) Z0, W± statistics, no hot medium effects  prod. mechanisms (gg vs. qqbar),  Q2 RAA, Rcp “easy” mix cold & hot nuclear effects (i.e. need pA) there is no golden normalization

Observables with bottomonia suppression 1: TC = 270 MeV, TD/TC = 4.0 (1.4) for ϒ(ϒ’) suppression 2: TC = 190 MeV, TD/TC = 2.9 (1.1) for ϒ(ϒ’) statistics: one month PbPb @ 5.5 TeV large sensitivity to dissociation temperatures and medium size ALICE: J. Phys. G 32 (2006) 1295, CMS: J. Phys. G 34 (2007) 2307

(gen - rec) vs. pt pp @ 14 TeV More with quarkonia polarization dN/dy in pp pp: test production mechanisms AA: probe QGP formation probe gluon distribution at low x (gen - rec) vs. pt pp @ 14 TeV pp @ 14 TeV: J/ &  pol. vs. pt PbPb @ 5.5TeV: J/  pol. vs. centrality,  pol. needs 2-3 runs R. Analdi, E. Scomparin, D. Stocco

Open charm & bottom: accessible channels charm: exclusive hadronic channels D0  K (tested in pp & PbPb) D+  K (tested in pp & PbPb) D±s  KK (under study) D*  D0 (under study) D0  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) b  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.) more exotic (and more challenging): QQbar  e, b  > 5 prongs, b  J/ + X, etc

Selected physics channels Quarkonia B from secondary J/ B from dileptons B from single leptons D0  K Heavy flavour quenching only “published” results

Secondary J/ from B hadron decay N(B  J/) / N(direct J/) ~ 20% in 4 @ LHC (d0) < 50 µm for pt > 1.5/2/3 GeV/c in ALICE/CMS/ATLAS disentangle primary & secondary J/ measure inclusive b cross-section probe b quark in-medium energy loss ALICE: CERN/LHC 2005-030, CERN/LHCC 99-13, ATLAS: EPJC 33 (2004) s1023, CMS: CMS NOTE 2006/031, 2001/008

Using secondary J/ from B decay to probe b quark energy loss secondary J/ from B decay in CMS, pt > 5 GeV/c energy loss is included in 2 scenarios: collisional energy loss collisional + radiative energy loss with energy loss: yield reduced by a factor ~ 4  distribution gets significantly narrower I.P. Lokhtin & A.M. Snigirev, Eur. Phys. J. C 21(2001)155

B signal from high-mass dimuons with vertexing  from BBbar  from Drell-Yan min-bias PbPb one month r > 50 m suppresses Drell-Yan rate by 2 orders of magnitude with ~ 30% loss of signal J. Phys. G 34 (2007) 2307

B signal from dimuons w/o vertexing unlike-sign total unlike-sign from bottom unlike-sign from charm like-sign from bottom unfold mass continuum large statistics is expected systematics to be estimated central PbPb (5%), one month Mass (GeV/c2) 0-5 5-20 N from bb 41461793 6983130 R. Guernane et al., ALICE-INT-2005-018, J. Phys. G 32 (2006) 1295

B hadron cross-section from single leptons pp @ 14 TeV B  +X First step: extract Nl  B w/o 2nd vertex: unfold lepton dN/dpt via combined fit large statistics constrains fit 107 PbPb (5%) evts (1 month) pt > 2 GeV/c, 200 < d0 < 600 m 80000 e from B, S/(S+B) = 80% 2.1·1012 pp evts (1 year) pt > 2 GeV/c 1.7·108  from B with 2nd vertex: cut on dca & subtract remaining background large purity of lepton sample PbPb @ 5.5 TeV B  e+X J. Phys. G 32 (2006) 1295, DIMUONnet

B hadron cross-section from single leptons Second step: correct for efficiency, acceptance & decay kinematics total number of lB integrated luminosity lepton global detection efficiency J. Phys. G 32 (2006) 1295, DIMUONnet

B hadron cross-section from single leptons Third step: the B-hadron inclusive differential cross-section w/o 2nd vertex with 2nd vertex B semi-muonic decays pp, s = 14 TeV method widely used (UA1, CDF, D0) large pt reach, (very) small statistical errors, systematics ~ 10-15% allows to get B RAA(pt), should work for charm as well similar performances to be expected in ATLAS & CMS J. Phys. G 32 (2006) 1295, DIMUONnet

background assumes dN/d = 6000 @  = 0 Hadronic charm cos(pointing) > 0.98 d0K  d0 < - 40 000 m2 increase S/B by 103 D0  K  (3.8%) c = 123 m 107 central PbPb (5%) S ~ 13000 S/B ~ 10 % S/(S+B) ~ 40 background assumes dN/d = 6000 @  = 0 J. Phys. G 32 (2006) 1295

Hadronic charm differential x-section system pp pPb PbPb s (TeV) 14 8.8 5.5 trig MB CC Nevt 109 108 107 time (months) 8 1 pt min (GeV/c) 0.5 Estat (%) 3 2 7 Esyst (%) 16 17 the most precise measurement of the total charm x-section in pp collisions @ LHC J. Phys. G 32 (2006) 1295

Testing QCD with hadronic charm in pp collisions @ 14 TeV mc, F/0, R/0, PDF bars: quadratic sum of statistical & systematic errors expected experimental errors are much smaller than theoretical uncertainties J. Phys. G 32 (2006) 1295

Heavy quark quenching: traditional ratios 1 nominal year: 107 central Pb-Pb events, 109 pp events statistics: bars, systematics: bands sensitivity to shadowing for pt <~ 7 GeV/c & to energy loss for pt >~ 7GeV/c J. Phys. G 32 (2006) 1295

Heavy quark quenching: more ratios 1 nominal year: 107 central Pb-Pb events, 109 pp events statistics: bars, systematics: bands sensitivity to color charge dependence sensitivity to mass dependence J. Phys. G 32 (2006) 1295

Heavy flavours at the LHC provide a rich physics program more analyses (not discussed here) are under study: heavy flavour flow, charm baryons, e- coincidences, b-tagged jets, Z0, W±,… first collisions in one month! Philippe.Crochet@clermont.in2p3.fr