(di-)leptons & heavy flavors in heavy ion collisions at the LHC (di-)leptons & heavy flavors: what is different at the LHC The LHC heavy ion program Selected physics channels quarkonia open heavy flavors low mass dileptons some more exotic channels

Recent activities in the field ALICE col. J. Phys. G 30 (2004) 1517; CMS col., CMS NOTE ; ATLAS col., CERN/LHCC/ Hard probes in heavy ion collisions at the LHC 4 working groups (PDF, shadowing and pA; Photons; Heavy quarks and quarkonia; Jet physics) 3 workshops 1 CERN Yellow Report: CERN (493 pages, 308 figures) Heavy quarkonium working group 6 working groups (Spectroscopy; Production; Quarkonium in media; Decays; Standard Model measurements; Future opportunities) 3 workshops 1 CERN Yellow Report: hep-ph/ (521 pages, 260 figures) HERA and the LHC 5 working groups (Parton density functions; Multi-jet final states and energy flow; Heavy quarks (charm and beauty); Diffraction; MC tools) 5 workshops written document in preparation

Heavy flavors: what is the LHC large primary production melting of  (1S) by color screening none of the primary J/  survives the (PbPb)QGP large secondary production of charmonia kinetic recombination, statistical hadronization, DD annihilation, b-hadron decay central AA RHIC LHC hard gluon induced quarkonium breakup hep-ph/

dimuons in ALICE, p  t > 2 GeV/c unlike-sign total unlike-sign from bottom unlike-sign from charm like-sign from bottom S.Grigoryan (di-)leptons: what is the LHC 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 charm pure NLO

Charm(onium) production, suppression, regeneration & in-medium modification interplay between different different time scales charm(onium) carries much more physics than anticipated systematic studies are a must time dropping mass, flow hadronic comovers kinetic recombination nuclear absorption color screening momentum fluctuations statistical hadronization quenching parton-(pre)resonance breakup p t broadening increased polarization parton cascade DD annihilation hard scattering, shadowing b decay

How well is the heavy flavor production x-section the LHC ? N. Carrer and A. Dainese, hep-ph/ theoretical uncertainties on absolute values: a factor 2-3 theoretical uncertainties on the  (5.5 TeV)/  (14 TeV) ratio: few %  measuring  (ccbar, bbbar) in pp 14 TeV is top priority

On the relevance of measuring  (b) in pp collisions in the first days  (b) in pp is mandatory for understanding  (b) in pA & AA (shadowing, quenching)  (b) in pp is mandatory for understanding  (  ) in pp, pA & AA (production, absorption, suppression)  (b) in pp is mandatory for understanding  (J/  ) in pp (& pA, AA) (N(b  J/  )/N(direct J/  ) ~ 30% in 4  w/o feed-down) open heavy flavor statistics is much larger than quarkonium statistics   (b) = day-one physics in pp the LHC

Heavy ion (ALICE) data taking scenario one LHC year = 7 months pp (10 7 s) + few weeks AA (10 6 s), starts in 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 (L int = 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 PbPb at low energy PbPb at 5.5 TeV & high luminosity ALICE collaboration, J. Phys. G 30 (2004) 1517

Heavy flavor physics LHC (channels investigated so far) charmonia & bottomonia versus centrality transverse momentum system-size reaction plane open bottom (inclusive) cross-section from 2 nd J/ , single leptons & dileptons b quark energy loss open charm (exclusive D’s) transverse momentum distribution c quark energy loss electron-muon coincidences

ATLAS: heavy ion LOI (2004) Heavy the LHC CMS: strong heavy ion program ALICE: the dedicated heavy ion experiment

ALICE (A Large Ion Collider Experiment) ITS TPC FMD PHOS ABSORBER MUON TRACKING CHAMBERS MUON FILTER DIPOLE MAGNETTOF TRD HMPID L3 MAGNET PMD MUON TRIGGER CHAMBERS 1000 members 80 instituts 30 countries

Heavy flavors with ALICE (di-)muons: J/ ,  ’, ,  ’,  ’’, open charm, open bottom (di-)electrons: J/ ,  ’, ,  ’,  ’’, open charm, open bottom hadrons: exclusive D 0 electron-muon coincidences: open charm & bottom

Heavy flavors with CMS muon spectrometer & silicon tracker in central barrel & end-caps large acceptance, excellent resolution J/ ,  ’, ,  ’,  ’’, open charm, open bottom

Heavy flavors with ATLAS muon spectrometer & silicon tracker in central barrel & end-caps large acceptance studies limited to  reconstruction & b-jet tagging so far

Acceptance for heavy flavor measurements nice complementarity between the 3 experiments ATLAS & CMS acceptance is large in  & limited to high p t ALICE combines hadrons, electrons, muons & covers low p t & high  ATLAS, CMS & ALICE-electrons/hadrons have inner tracking

Quarkonium measurements in ATLAS  &  ’ can be well separated  ’ &  ’’ separation is difficult J/  studies underway barrel (|  |<1) |  |<1|  |<2.5 accep. + efficiency4.9 %14.3% resolution (MeV) CERN/LHCC/ , L.

Quarkonium measurements in CMS  M(dimuon) ~ 60 M = 10 GeV in central barrel background mainly coming from uncorrelated muon-pairs J/  reconstruction limited to high p t G. Baur et al., CMS NOTE

Quarkonium measurements in ALICE background level 1 = 2 HIJING evts with dN ch /d  =  = 0 each  mass resolution acceptance dielectrons dimuons J/  measurement down to p t = 0 the LHC) resolution allows to separate the 3  states note: no need for J/  trigger (at least in central PbPb collisions) p t > 3 GeV/c trigger p t > 1 GeV/c trigger p t > 2 GeV/c trigger

cross-sections from R. Vogt in hep-ph/ , assumes neither suppression nor enhancement J/  : large stat., good sign. (allows much narrower centrality bins)  ’: small S/B  : good stat., S/B > 1, good sign.  ’: good stat., S/B > 1, good sign.  ’’: low statistics similar rates for  in the dielectron channel Centrality dependence of quarkonium yields in ALICE-muon S. Grigoryan (updated Dec.’04)

 ’/  ratio versus p t E. Dumonteil, PhD Thesis (2004) E. Dumonteil & P. Crochet, ALICE-INT Melting depends on resonance formation time, dissociation temp. & p t QGP temp., lifetime & size Ratio is flat in pp (CDF) Any deviation from the pp (pA) value is a clear evidence for the QGP (nuclear effects cancel-out) The p t dependence of the ratio is sensitive to the characteristics of the QGP 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 full & realistic simulation error bars = 1 month of central PbPb (10%)

b-hadron cross-section from single muons & unlike-sign dimuons in PbPb 1) get N b  from fits with fixed shapes (PYTHIA) & b yield as the only free parameter # R. Guernane et al., (2004) *C. Albajar et al., PLB 213 (1988) 405; PLB 256 (1991) 121 p t (GeV/c) N  from b     8 Mass (GeV/c 2 ) N  from bb   130 UA1 MC method* used by CDF & D0, applied here # to central PbPb (5%)

b-hadron cross-section from single muons & unlike-sign dimuons in PbPb 2) for each  sample, correct N b  for eff. & N evt, then convert to hadron cross-section total number of b  from the fit integrated luminosity  global detection efficiency R. Guernane et al., (2004), C. Albajar et al., PLB 213 (1988) 405; PLB 256 (1991) 121

b-hadron cross-section from single muons & unlike-sign dimuons in PbPb 3) the b-hadron inclusive differential cross-section distribution R. Guernane et al., (2004) input distribution well reconstructed agreement between the 3 channels statistics is (very) large systematic uncertainties underway “measured data points” input distribution “a nice illustration that one can use Tevatron- like analyzes in PbPb the LHC”

Bottom from single electrons with displaced vertices PbPb central (5%) B  e  in ITS/TPC/TRD p t > 2 GeV/c, 200 < d0 < 600  m e  from B, S/(S+B) = 90% d0 < d0cut: improve S/B for resonances d0 > d0cut: measure electrons from D & B CERN/LHCC 99-13, R. Turrisi, CERN HIF, 04/13/05

b-hadron inclusive differential cross-section from single electrons R. Turrisi CERN HIF, 04/13/05 E- loss calculations: N. Amesto, A. Dainese, C.A. Salgado, U.A. Wiedemann, Phys. Rev. D 71 (2005) same method as the one used with (di-)muons plus scenario for b-quark energy loss electrons with 2 < p t < 16 GeV/c  b-hadrons with 2 < p t min < 23 GeV/c clear sensitivity to energy loss will be further used to get R AA b-hadrons R AA h, R AA D0 & R AA b-hadrons can be measured simultaneously A. Dainese, nucl-ex/ , nucl-ex/

From NA50’s (J/  )/DY to ALICE’s  /bbbar (assuming no quenching on b quarks) w/o  nuclear absorption with  nuclear absorption statistics: one month PbPb statistics of the reference is in 5<M<20GeV ~5 times larger than that of the probe errors dominated by uncertainties on  nuclear absorption (~20%) systematic errors underway R. Guernane & S. Grigoryan (2004) EPJC 39 (2005) 335

The Z 0 as a normalisation to bottomonium suppression most natural normalization to  is b (assuming quenching is under control!) Z 0 : “clean” signal for normalisation (alternative to Drell-Yan which is out of reach) not an universal normalisation (different shadowing for quarks & gluons) CMS/NOTE 2001/008 Z 0 in CMS: b-hadron decays dominate the dimuon imass 2 weeks L = cm -2 s -1 : Z 0   +  - in |  | < 2.5

Secondary J/  from B decay ALICE: CERN/LHCC 99-13, CMS: CMS/NOTE 2001/008 disentangle primary & secondary J/  measure inclusive b cross-section probe b quark in-medium energy loss B  J/  (1S) anything: 1.16  0.10% (PDG) N(direct J/  ) in central (5%) 5.5 TeV: 0.31 N(bbbar pairs) in central (5%) 5.5 TeV: 4.56  N(b  J/  ) / N(direct J/  ) = 34% in 4 

b-hadron cross-section from secondary J/  in  s = 1960 GeV (CDF results) D. Dacosta et al., Phys. Rev. D 71 (2005)

Using secondary J/  from B decay to probe b quark energy loss energy loss is modeled in 2 extreme cases: collisional energy loss (minimum) collisional + radiative energy loss (maximum) with energy loss: yield reduced by a factor ~ 4  distribution gets significantly narrower secondary J/  from B decay in CMS, p t  > 5 GeV/c I.P. Lokhtin & A.M. Snigirev, Eur. Phys. J. C 21(2001)155 interest to combine this study with dimuons from b-hadrons

Low mass dilepton measurements CERN/LHCC 99-13, B. Rapp, PhD thesis feasible in pp collisions (with p t l > 0.5 GeV/c & with Dalitz rejection in e + e - ) challenging in PbPb collisions (min p t l threshold = 1 GeV/c, trigger & bgd) acceptance limited to high p t excluded in ATLAS & CMS ALICE dielectrons, central PbPb, p t > 1 GeV/c ALICE dimuons, proton-proton, p t > 0.5 GeV/c ALICE dimuons, central PbPb, p t > 1 GeV/c

Some more exotic channels Secondary J/  from tri-muon events in pp w/o 2 nd vertex b measurements from like-sign dileptons electron-muon coincidences Z  measurements

dimuon events: 85% of direct J/  15% of J/  from b decay tri-muon events: 15% of direct J/  85% of J/  from b decay Secondary J/  from tri-muon events in pp w/o 2 nd vertex reconstruction dimuon evts in pp, p  t > 1GeV/c b-chain S/B = 3 S/√S+B = 80 tri-muon evts in pp, p  t > 1GeV/c correlated muons correlated muons from b uncorrelated muons A. Morsch (2004) doable in pp & pA, very difficult in central ArAr

b measurements from like-sign dileptons 2 sources of like-sign correlated dileptons: like-sign correlated b ~ unlike-sign correlated c B 0 oscillations ~ 30% of total like-sign correlated clean signal (D mesons do not oscillate) signal measurable via (like-sign)-(event-mixing) P. Crochet & P. Braun-Munzinger, Nucl. Instrum. Meth. A 484(2002)564

Electron-muon coincidences clean signal covers intermediate rapidities measurement done in ISR (1979!) challenging in heavy ion collisions ALICE-INT

Z  measurements with the ALICE muon spectrometer Z. Conesa del Valle, DIMUONnet’05 14 TeV: accep ~ 14 %    /run 5.5TeV: accep ~ 10.8 %    /run background studies underway asymmetries in production & decay due to valence quarks acceptance PbPb

(di-)leptons & heavy flavors in heavy ion collisions at the LHC new environment, large statistics, new observables, new analyzes  rich physics program further possibilities with dileptons B +  J/  K +, B 0  J/  K 0 s, B 0 s  J/  ,  b  J/   à la CDF & D0 quarkonium & open heavy flavor flow quarkonium polarization dilepton correlations first data in April stay tuned

Recent results from CDF

B measurements à la CDF A.Dainese, nucl-ex/ ,

Low mass resonances: acceptance    w/o p t cut p t  1 GeV/c p t  0.5 GeV/c

ALICE PID

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Tracking & Vertexing D mesons c  ~ 100–300  m, B mesons c  ~ 500  m Secondary vertex capabilities!  Impact param. resolution! acceptance: p t > 1 GeV/c r  2.5 GeV/c  p t /p t < 2% up to 100 GeV/c acceptance: p t > 0.2 GeV/c r  1.5 GeV/c  p t /p t < 2% up to 10 GeV/c < 9% up to 100 GeV/c B = 0.5 T B = 4 T A.Dainese, SQM04