Quarkonia in heavy ion collisions @ LHC heavy flavors & (di)leptons @ LHC detector performances selected physics channels Philippe.Crochet@clermont.in2p3.fr

Heavy flavors: what is different @ the LHC central AA large primary production melting of (1S) by color screening none of the primary J/ survives the (PbPb)QGP a lot of charmonia from b hadron decay large secondary production of charmonia statistical hadronization, kinetic recombination, DD annhililation RHIC LHC hard gluon induced quarkonium breakup hep-ph/0311048 Philippe.Crochet@clermont.in2p3.fr

(di)leptons: what is different @ the LHC dimuons in ALICE, pt > 2 GeV/c unlike-sign total unlike-sign from bottom unlike-sign from charm like-sign from bottom charm pure NLO Z. Conesa del Valle (2005)  in ALICE pp @ 14TeV S. Grigoryan (2004) large & complex combinatorial background dileptons from b decay dominate the spectrum below  & J/ large yield of secondary J/ from b decay dileptons from b decay have different origin at low & high mass sizeable yield of like-sign correlated dileptons from b decay W stick out from single lepton spectra with large statistics Philippe.Crochet@clermont.in2p3.fr

J/ from b decay in central PbPb @ 5.5 TeV b  J/ (1S) anything : 1.16  0.10% (PDG) N(direct J/) in central (5%) PbPb @ 5.5 TeV : 0.49* N(bb pairs) in central (5%) PbPb @ 5.5 TeV : 4.56#  N(b  J/) / N(direct J/) ~ 20% in 4 (22% in pp @ 14 TeV) (with shadowing & feed-down, w/o nuclear absorption, suppression, regeneration…) this is a lot! no obvious way to disentangle prompt & secondary J/ from pt dist. (only 2nd vertexing or b measurement can help) *from CERN-2004-009, hep-ph/0311048, CEM, underpredicts CDF data by a factor 2 #from ALICE PPR VII, CERN/LHCC 2005-030, uncertainty: a factor 2-3 (mQ, F, R, PDF) Philippe.Crochet@clermont.in2p3.fr

using (2s) to unravel J/ suppression vs. regeneration One physics case: on the relevance of measuring  in heavy ion collisions at the LHC using (2s) to unravel J/ suppression vs. regeneration J/ suppression & regeneration? c suppression (J/ TD > 1.5 Tc)? H. Satz, CERN Heavy Ion Forum, 09/06/05 enhanced suppression enhanced regeneration TLHC >> J/ TD ~ (2s) TD C.-Y. Wong, PRC 72 034906 W.M. Alberico et al., PRD 72 114011  regeneration is small L. Grandchamp et al., hep-ph/0507314 SPS RHIC LHC 30

M.Rosati Tuesday parallel II Heavy ions @ the LHC CMS: strong heavy ion program D.d’Enterria Tuesday parallel II ATLAS: heavy ion LOI (2004) M.Rosati Tuesday parallel II ALICE: the dedicated heavy ion experiment

ALICE (A Large Ion Collider Experiment) TOF DIPOLE MAGNET HMPID TRD ACORDE L3 MAGNET PMD FMD ITS MUON TRIGGER CHAMBERS TPC PHOS MUON FILTER ABSORBER MUON TRACKING CHAMBERS

How LHC detectors measure quarkonia nice complementarity between the 3 experiments ATLAS & CMS acceptance is large in  & limited to high pt ALICE acceptance covers low pt & high  ATLAS, CMS & ALICE-electron have inner tracking

LHC inner trackers expected performances (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

Transverse momentum acceptance for quarkonia measurements CMS J/ ALICE J/  e+e- acceptance || < 2.4 barrel ALICE can measure J/ down to 0 pt (unique @ LHC) ATLAS acceptance similar to CMS acceptance for J/ in central barrel ALICE, ATLAS & CMS can measure  down to 0 pt note: ≠ trigger & reconstruction efficiencies (expected statistics doesn’t scale with geo. acc.!) w/o trigger with trigger ALICE J/  µ+µ- ALICE: PPRVII, CERN/LHCC 2005-030, CMS: NOTE 2006/089

background level 1 = 2 HIJING evts with dN/d = 6000 @  = 0 each  mass resolution (  100 MeV @ M ~ 10 GeV is needed to separate the  sub-states) CMS dN/d = 2500 || < 2.4  ~ 90 MeV CMS no bkg || < 0.8  ~ 54 MeV ALICE electron dN/d = 6000 ATLAS dN/d = 3000 || < 2  ~ 145 MeV background level 1 = 2 HIJING evts with dN/d = 6000 @  = 0 each ALICE muon warning: ≠ simulation frameworks & inputs ongoing analyses ALICE: PPRVII, CERN/LHCC 2005-030, ATLAS: CERN/LHCC/2004-009, CMS: NOTE 2006/089

Expected statistics in ALICE-muon 1 LHC year = 7 months pp (107s, 3·1030cm-2s-1) + 1 month AA (106s, 5·1026cm-2s-1) J/ ’  ’ ’’ PbPb MB 5.5 TeV S (103) 681.4 18.92 6.33 1.8 1.02 S/B 0.33 0.02 2.46 1.03 0.74 S/S+B 413 19.53 67.14 30.19 20.85 pp 14 TeV 4670 122 44.7 11.4 6.9 12.6 0.55 5.8 1.9 1.3 2081 209 195 86 62 full simulation including realistic geometry trigger efficiency reconstruction efficiency tracking efficiency resolutions from PbPb MB to pp, a factor ~ 10 more stat. J/: large stat., good significance ’: small S/B : good stat., S/B > 1, good significance ’: good stat., S/B > 1, good significance ’’: low statistics ALICE PPR VII, CERN/LHCC 2005-030, x-sections from CERN-2004-009, hep-ph/0311048, with shadowing & feed-down, w/o nuclear absorption/suppression/regeneration…

From NA50’s (J/)/DY to ALICE’s /bbbar EPJC 39 (2005) 335 NA50 PbPb @ 17GeV ALICE PbPb @ 5.5TeV statistics : one month PbPb (b) extracted à la UA1, CDF, D0 statistics of the reference is in 5<M<20GeV ~5 times larger than that of the probe systematic errors underway ALICE PPRVII, CERN/LHCC 2005-030 dissociation temperatures: C.-Y. Wong, PRC 72 034906 & W.M. Alberico et al., PRD 72 114011

’/ ratio versus pt melting depends on J.P. Blaizot & J.Y. Ollitrault, Phys. Lett. B 199(1987)499; F. Karsch & H. Satz, Z. Phys. C 51(1991)209; J.F. Gunion & R. Vogt, Nucl. Phys. B 492(1997)301 melting depends on resonance formation time, dissociation temp. & pt QGP temp., lifetime & size ratio is flat in ppbar (CDF) any deviation from the pp (pA) value is a clear evidence for the QGP (nuclear effects cancel-out) the pt dependence of the ratio is sensitive to the characteristics of the QGP full & realistic simulation error bars = 1 month of central PbPb (10%) E. Dumonteil, PhD Thesis (2004), ALICE-INT-2005-002

Using b decays to probe the QGP a measurement of (J/)/(b) = (2)1% or ’/(J/) = 0.0625 is an evidence for full J/ suppression (& no regeneration!) no need to disentangle prompt & secondary J/! ALICE PPRVII, CERN/LHCC 2005-030

Instead of a summary, what will happen next year 2008 Jan. Aug. Sept. Oct. Nov. Dec. Feb. Mar. Apr. May Jun. July 2007 10 weeks pp machine closure set-up, injection shut-down pp high L, 1st PbPb… first physics run! Philippe.Crochet@clermont.in2p3.fr

BACKUP

Heavy ion (ALICE) data taking scenario one LHC year = 7 months pp (107s) + 1 month AA (106s), starts in 2007 5 first years: regular pp runs at 14 TeV: commissioning, reference, dedicated pp physics first PbPb run at low luminosity: global observables, large x-sections 2 PbPb runs at high luminosity (Lint = 0.5nb-1/year): small x-sections 1 pA run: structure functions, hadronic reference 1 light ion run: energy density dependence later (different options depending on the first results): pp (or pp-like) at 5.5 TeV other light or intermediate-mass systems other systems p-likeA & Ap-like PbPb at low energy PbPb at 5.5 TeV & high luminosity ALICE collaboration, J. Phys. G 30 (2004) 1517

Combined momentum resolution at low momentum dominated by - ionization-loss fluctuations - multiple scattering at high momentum determined by - point measurement precision - alignment & calibration (assumed ideal here) resolution ~ 7% at 100 GeV/c excellent performance in hard region! F. Antinori, 06/20/05