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

3. Outline 1) Features of R CP and v 2 for Particle Production at Intermediate p T 2) Charm R AA and v 2 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  R AA or R CP = 1 simple superposition of independent nucleon-nucleon collisions !

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

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

7. Particle Dependence of R CP (R AA ) Particle production at the intermediate p T (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. Elliptic Flow Parameter v 2 y x pypy pxpx coordinate-space-anisotropy  momentum-space-anisotropy Initial/final conditions, dof, EOS

9. y Dynamical Origin of Elliptic Flow V 2 in the high p T region: Due to parton energy loss? Particle dependence of v 2 ? Collective Pressure High pressure gradient Large expansion velocity Small expansion velocity p T dependent ! Surface Geometrical Phase Space Surface Emission Pattern High particle density Low particle density p T independent ! or p T dependence may come from surface thickness (p T ) x

10. STAR PHENIX Particle Dependence of v 2 Baryon Meson Unique baryon and meson difference !! Run II

11. PHENIX (open symbols): Phys. Rev. Lett. 91, 182301 (2003) Very Much Improved Data !! Meson-Baryon Scaling in v 2 at Intermediate p T !!

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

13. Quark Cluster Formation from Strongly Interacting Partonic Matter Volcanic mediate p T – Spatter (clumps)   Mesons – effective DOF  2 Baryons – effective DOF  3 when formed from the bulk partonic matter ! Particle v 2 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 (R AA /R CP and v 2 )  all constituent quarks are almost equally important in determining particle properties ! v 2 of hadron comes from v 2 of all constituent quarks ! The fact that in order to explain the v 2 of hadrons individual constituent quarks (n=2-meson,3-baryon) must have a collective elliptic flow v 2 and the hadron v 2 is the sum of quark v 2  Clear Evidence for Deconfiement !

15. 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 Total Charm Production Binary Scaling ! STAR Preliminary

16. Does Charm Quark Flow Too ? Reduce Experimental Uncertainties !! Suppression in R AA  Non-zero azimuthal anisotropy v 2 !

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

18. J/psi is suppressed in central Au+Au Collisions ! Factor ~ 3 the same as that at SPS Satz: Only  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. V 2 of J/psi V 2 of J/psi can differentiate scenarios ! pQCD direct J/psi should have no v 2 ! Recombination J/psi can lead to non-zero v 2 !

20. The case for partonic DOF/Deconfinement can be made with strange vector meson  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. Particle Dependence of R CP suppression Run II Data R cp = {Yield/Ncoll} Central {Yield/Ncoll} Peri

27. p T Scales and Physical Processes R CP Three P T 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 p T particles the initial parton is considerably harder than if only one high p T particle is produced. Fragmentation region p T > 5.5 GeV/c 3) low level two particle correlations in the soft region can be accommodated in recombination/coalescence (wave induced correlation?)