1. Loïc Grandchamp Lawrence Berkeley National Laboratory “Probing QCD with High Energy Nuclear Collisions” Hirschegg, Jan. 16-22 ’05 with H. van Hees, S. Lumpkins, R. Rapp, D. Sun Quark(onium) Production in URHICs

2. Motivations / Introduction Charm & bottom in HI collisions produced early, small HG int. ) probe the medium energy loss coalescence thermalization two mass scales: m c ' 1.5 GeV, m b ' 5 GeV in-medium modifications heavy-light systems,  –symmetry restoration resonances in QGP, quarkonia above T c Quark(onium) evolution & timescales Nuclear absorption N cc frozen Thermal QGP Mixed phase Suppression/Regeneration Hadron gas Thermal Freezeout Free streaming

3. Outline This talk Heavy quarks and quarkonia in matter Lattice QCD Charmonia in QGP, HG C-quark thermal equilibration Charmonium equilibrium numbers Rate equations Quarkonium in A-A collisions Charmonium at SPS & RHIC  ’/  ratio Lighter systems Bottomonium Not in this talk Open-charm production in pp (expts. + N coll scaling) Nuclear suppression (  nuc from expts.)

4. Lattice QCD heavy quark Free energy [Karsch et al. ’00] Reduction of the open charm threshold Even below T c Smooth transition across T c ) medium effects: m c ¤, m D ¤,  ’/  ratio Heavy quarks & lattice QCD Spectral functions from Lattice [Umeda et al. ’02] Low-lying charmonia survive in the QGP Mass  constant Large width increase across T c Charmonium lifetimes

5. Quarkonium above T c gluodissociation [Bhanot, Peskin ‘79]  0 >>  QCD “quasifree” [LG + R. Rapp ’01]  0 »  QCD Reduced in-medium  0 ) quasifree more efficient ) applicable for  ’, 

6. Quarkonium below T c Hadronic interactions (vacuum) Inefficient (small densities) Even for excited states In-medium effects % inel. collisions & DD threshold  ’  fragile J/  robust [Navarra et al.] M.Ex CQM QCD-SR pQCD [LG + R. Rapp ’03]

7. P ? -spectra: insensitive, null effect [Batsouli etal. ‘02] Similarly for D-meson from coalescence [Greco etal. ‘03] PHENIX 130AGeV e±e± D Pythia Thermal + flow PHENIX 200AGeV D-meson coalescence C-quark interactions: Thermalization ? B bottom charm Elliptic flow: v 2 (e § ) needs confirmation N f =4 QGP !? [PHENIX Prelim] [STAR Prelim] Possible mechanism : [van Hees + Rapp ’04] resonant open-charm rescattering c + q ! “D” ! c + q isotropic ! more efficient than pQCD

8. Quarkonium equilibrium numbers [LG + R. Rapp ’03]

9. Statistical hadronization at T c Quarkonia above T c ) regeneration in QGP Detailed balance: Quarkonium evolution in URHICs Thermal c-quark:  , N  eq : medium effects Link to Lattice QCD Convolute over fireball expansion Include feeddown Chemical off-equilibrium  c Thermal off-equilibrium R [Braun-Munzinger +Stachel ’01 Gorenstein etal. ’02] [Thews etal. ’01 Ko etal. ’02 LG + R. Rapp ‘02]

10. [LG + R. Rapp ’03] Centrality dependence SPS Pb(158 AGeV)-PbRHIC 200 Au-Au SuppressionRegeneration Charmonium in A-A Excitation function  Transition “direct suppressed”  “statistical” SPS RHIC

11. Charmonium in A-A Medium effects:  ’/  ratio

12. Lighter systems SPS In(158 AGeV)-InRHIC 200 Cu-Cu QGP Suppression regime Upcoming NA60 results 50% direct 50% regenerated Onset of regeneration Centrality dependence Medium effects:  ’/  ratio NA60: In(158 AGeV)-In Still sensitive to in-medium effects Fireball thermalization in peripheral collisions ?

13. Model approaches at RHIC Suppression only [Kostyuk etal. ’02] Statistical Hadronization [Andronic etal. ’02] Suppression+Regeneration [Thews etal. ’03] equilibrium & off-equilibrium scenarios ) strong sensitivity to N cc

14. Bottomonium in A-A RHIC LHC Suppression prevails even at LHC ) “Control experiment” for charm regeneration [S. Lumpkins etal. ’05]

15. Model of charmonium production in A-A Survival of charmonia above T c Reduction of the open charm threshold + Rate equations SPS: charmonium suppression RHIC: charmonium regeneration Bottomonium suppression at RHIC & LHC Various observables, systems, energies Outlook C-quark thermalization ?! V 2 (e § ) needs confirmation V 2 (J/  ) P ? -distributions Conclusions QGP

16. Quark(onium) production in URHICs Extra Slides

17. Open Charm Production NN collisions LO pQCD: K ~ 4-7 NLO: K ~ 2-3 pA collisions Scaling AA collisions SPS central Pb-Pb RHIC central Au-Au

18. Primordial J/  : Pre-Eq Effects Nuclear absorption AA collisions L: nuclear path length  nuc : 4.4 mb 50% effect in Pb-Pb at SPS RHIC Nuclear absorption ? NN collisions: ~ 1% of cc pairs form a quarkonium state pA collisions:

19. Thermal Fireball evolution Expanding thermal fireball Trajectory in (  B, T) plane at constant S and N B Quasiparticle-QGP / resonance HG equation of state Cylindrical expansion Parameters fitted to Final flow velocities Hadro-chemistry Consistency with Chemistry Hydrodynamics Dilepton yields

20. In-Medium Effects - II

21. High E T Effects in NA50 Transverse energy fluctuations at b=0 [Capella, Ferreiro & Kaidalov ’00] [Blaizot, Dinh & Ollitrault ’00] ET > 100 GeV Extra suppression Minimum Bias analysis [Capella, Kaidalov & Sousa ’01] Trigger energy loss ?

22. Other QGP Suppression Mechanisms

23. Minimum Bias Analysis

24. Dilepton Spectra