Strange and Charm Probes of Hadronization of Bulk Matter at RHIC

1. Strange and Charm Probes of Hadronization of Bulk Matter at RHIC International Symposium on Multi-Particle Dynamics Aug 9-15, 2005 Huan Zhong Huang University of California at Los Angeles

2. Volcanic high pT -- Strombolian eruption Volcanic mediate pT – Spatter (clumps) Volcanic low pT – Bulk matter flows Probes of Dense Matter in Nature

3. Outline 1) Features of RCP and v2 for Particle Production at Intermediate pT 2) Charm RAA and v2 3) Hadronization of Defined Partonic Matter 4) Implications for QCD Matter at Hadronization and LQCD Expectation

4. Nuclear Modification Factors Use number of binary nucleon-nucleon collisions to gauge the colliding parton flux: N-binary Scaling  RAA or RCP = 1 simple superposition of independent nucleon-nucleon collisions !

5. Fragmentation sets in at pT > 5.5 GeV/c or so !! Fragmentation Meson-Baryon Scaling at Intermediate pT !!

6. There is something special at intermediate pT even in neutral pion and eta too !!

7. Particle Dependence of RCP(RAA) Particle production at the intermediate pT (2-5 GeV/c) 1) meson-baryon yields depend on collision centrality (parton density) 2) Meson-baryon scaling – the dependence is only on particle-type (meson versus baryon), not explicitly on particle mass.

8. coordinate-space-anisotropy  momentum-space-anisotropy y py px x Initial/final conditions, dof, EOS Elliptic Flow Parameter v2

9. y Small expansion velocity Collective Pressure High pressure gradient Large expansion velocity pT dependent ! Low particle density Surface Geometrical Phase Space Surface Emission Pattern High particle density pT independent ! or pT dependence may come from surface thickness (pT) Dynamical Origin of Elliptic Flow x V2 in the high pT region: Due to parton energy loss? Particle dependence of v2 ?

10. STAR PHENIX Particle Dependence of v2 Run II Baryon Meson Unique baryon and meson difference !!

11. Very Much Improved Data !! Meson-Baryon Scaling in v2 at Intermediate pT !! PHENIX (open symbols): Phys. Rev. Lett. 91, 182301 (2003)

12. solid: STAR open: PHENIX PRL91(03) Constituent Quark Degree of Freedom Why does the meson-baryon scaling work so well ?

13. Volcanic mediate pT – Spatter (clumps) Quark Cluster Formation from Strongly Interacting Partonic Matter L X W Mesons – effective DOF  2 Baryons – effective DOF  3 when formed from the bulk partonic matter ! Particle v2 may be related to quark matter azimuthal anisotropy !!

14. Multi-Parton Dynamics for Bulk Matter Hadronization Essential difference: Traditional fragmentation  particle properties mostly determined by the leading quark ! Emerging picture from RHIC data (RAA/RCP and v2)  all constituent quarks are almost equally important in determining particle properties ! v2 of hadron comes from v2 of all constituent quarks ! The fact that in order to explain the v2 of hadrons individual constituent quarks (n=2-meson,3-baryon) must have a collective elliptic flow v2 and the hadron v2 is the sum of quark v2  Clear Evidence for Deconfiement !

15. Total Charm Production Binary Scaling ! STAR Preliminary 1.13  0.09(stat.)  0.42(sys.) mb in 200GeV minbias Au+Au collsions Total charm  Binary Scaling suppression at high pT J/psi not significantly enhanced Contrary to ReC- models

16. Does Charm Quark Flow Too ? Reduce Experimental Uncertainties !! Suppression in RAA Non-zero azimuthal anisotropy v2 !

17. Non-photonic Electrons Strongly Suppressed Too ! STAR and PHENIX agree Beauty and Charm Contributions ? Energy Loss of Heavy Quarks?

18. J/psi is suppressed in central Au+Au Collisions ! Factor ~ 3 the same as that at SPS Satz: Only c states are screened both at RHIC and SPS. Alternative: Larger suppression in J/psi at RHIC due to higher gluon density, but recombination boosts the yield up !

19. V2 of J/psi V2 of J/psi can differentiate scenarios ! pQCD direct J/psi should have no v2 ! Recombination J/psi can lead to non-zero v2 !

20. The case for partonic DOF/Deconfinement can be made with strange vector meson f cannot be made from KK coalescence !

21. Summary Effective partonic DOF has been observed to be important for Hadronization of Bulk Partonic Matter Empirically the Parton Degrees of Freedom Scale as the Number of Constituent Quarks (n=2 for M, 3 for B) If So, the Dense Matter Must Be Deconfined

22. The Missing Links • The Initial State from the Collision must be dominated • by gluons (Temperature?) Parton Evolutions (?) • At the Hadronization Stage the dominate degrees of freedom are constituent quarks (or quasi-hadrons) (Empirical) What is the parton evolution dynamics?? Is this what spectral function result from LQCD implies? Empirically the dense matter with collective motions of constituent quark degrees of freedom must be preceded with a deconfined partonic matter, BUT we do not have any experimental indication that this is a phase transition !

24. The End

25. Strange quark dynamics are not significantly different from light quarks Partonic Collectivity at RHIC!

26. {Yield/Ncoll}Central Rcp= {Yield/Ncoll}Peri Particle Dependence of RCP Run II Data suppression

27. pT Scales and Physical Processes RCP Three PT Regions: -- Fragmentation -- multi-parton dynamics (recombination or coalescence or …) -- Hydrodynamics (constituent quarks ? parton dynamics from gluons to constituent quarks? )

28. Two Particle Jet-like Correlations Jet-like two particle correlations (e.g., trigger particle 4-6 GeV/c, associated particle 2-4 GeV/c) : These correlations cannot be easily explained in terms of recombination/coalescence scenario ! But 1) the effect of resonances on the two particle correlations has not be adequately addressed 2) trigger biases – with two high pT particles the initial parton is considerably harder than if only one high pT particle is produced. Fragmentation region pT > 5.5 GeV/c 3) low level two particle correlations in the soft region can be accommodated in recombination/coalescence (wave induced correlation?)