1. ISMD’05, Kromeriz, Aug 09  15, 2005 1 Heavy  Flavor (c,b) Collectivity – Light  Flavor (u,d,s) Thermalization at RHIC Kai Schweda, University of Heidelberg People:S. Blyth, X. Dong, Y. Lu, M. Oldenburg, H.G. Ritter, A. Rose, A. Shabetai, P. Sorensen, N. Xu, H. Zhang, Y. Zhang.

2. ISMD’05, Kromeriz, Aug 09  15, 2005 2 Outline 1)Introduction 2)Multi-strange baryons elliptic flow 3)Charm-quark flow 4)Summary

3. ISMD’05, Kromeriz, Aug 09  15, 2005 3 Quark Gluon Plasma Source: Michael Turner, National Geographic (1996) Quark Gluon Plasma: (a)Deconfined and (b)thermalized state of quarks and gluons  Study partonic EOS at RHIC (?) Probe thermalization using heavy-quarks

4. ISMD’05, Kromeriz, Aug 09  15, 2005 4 Time Scale 1)Coalescence processes occur during (phase) transition and hadronization; 2)u-,d-quarks and ‘bound-states’ gain mass accompanied by expansion; 3)Early thermalization with partons and its duration need to be checked. deconfinement Phase and Chiral transitions u-, d-quarks and ‘bound- states’ gain mass

5. ISMD’05, Kromeriz, Aug 09  15, 2005 5 1) Compared to , K, and p, multi-strange particles , multi-strange particles ,  are found at lower  are found at lower but higher T ~ T ch  Collectivity prior to hadronization  Collectivity prior to hadronization 2) Sudden single freeze-out*: Resonance decays lower T fo for ( , K, p)  Collectivity prior to hadronization Partonic Collectivity ? Partonic Collectivity ? Kinetic Freeze-out Data: Data: STAR preliminary Au+Au@200GeV: Nucl. Phys. A715, 129c(2003). *A. Baran, W. Broniowski and W. Florkowski; nucl-th/0305075 STAR Preliminary

6. ISMD’05, Kromeriz, Aug 09  15, 2005 6 Anisotropy Parameter v 2 y x pypy pxpx coordinate-space-anisotropy  momentum-space-anisotropy Initial/final conditions, EoS, degrees of freedom

7. ISMD’05, Kromeriz, Aug 09  15, 2005 7 v 2 in the Low-p T Region - Minimum bias data! At low p T, model result fits mass hierarchy well! - Details does not work, need more flow in the model! P. Huovinen, private communications, 2004

8. ISMD’05, Kromeriz, Aug 09  15, 2005 8 Collectivity, Deconfinement at RHIC - v 2, spectra of light hadrons and multi-strange hadrons - scaling with the number of constituent quarks At RHIC, it seems we have:  Partonic Collectivity êDeconfinement  Thermalization ? PHENIX: PRL91, 182301(03) STAR: PRL92, 052302(04) S. Voloshin, NPA715, 379(03) Models: Greco et al, PRC68, 034904(03) X. Dong, et al., Phys. Lett. B597, 328(04). ….

9. ISMD’05, Kromeriz, Aug 09  15, 2005 9 Partonic Collectivity at RHIC 1) Copiously produced hadrons freeze-out: T fo = 100 MeV,  T = 0.6 (c) >  T (SPS) 2) Multi-strange hadrons freeze-out: T fo = 160-170 MeV (~ T ch ),  T = 0.4 (c) 3) Multi-strange v 2 : Multi-strange hadrons  and  do flow! 4) Constituent Quark scaling: Seems to work for v 2 and R AA (R CP ) Deconfinement & Partonic (u,d,s) Collectivity !

10. ISMD’05, Kromeriz, Aug 09  15, 2005 10 Heavy-Flavor Quarks Plot: B. Mueller, nucl-th/0404015.  Symmetry is broken:  QCD dynamical mass  EW Higgs mass  Even in a QGP, charm and beauty quark-mass heavy !  Charm(Beauty) good probe for medium created at RHIC  If heavy quarks flow:  frequent interactions among all quarks  light quarks (u,d,s) likely to be thermalized Plot: B. Mueller, nucl-th/0404015. Mass (MeV/c 2 ) 10 6 10 5 10 4 10 3 10 2 10 1

11. ISMD’05, Kromeriz, Aug 09  15, 2005 11 Charm-quark Elliptic Flow V. Greco et al., PLB 595(2004)202 Coalescence approach Large X-sec needed to reach large v 2 → Charm quark flows → Indication of light flavor thermal equilibrium! Theoretical justification of the large cross section? AMPT transport model B. Zhang et al., nucl-th/0502056

12. ISMD’05, Kromeriz, Aug 09  15, 2005 12 V. Greco et al. PLB 595(2004)202 Non-photonic electron v 2  Experimental data do not agree at 2<p T (e)<5 GeV/c!  v 2 (e) favors non-zero v 2 (c) at p T (e)<2 GeV/c. B. Zhang et al. nucl-th/0502056 c (b)  e + X

13. ISMD’05, Kromeriz, Aug 09  15, 2005 13 Two extreme scenarios: (a) No charm quark flow (PYTHIA) (b) Charm quark flow (Hydro)  Differences in D-meson spectra ~30% at p T < 2.0 GeV/c D  e + X: electron spectra undistinguishable !  Information on charm-dynamics washed out  Need direct open charm reconstruction to low p T ! Open Charm Flow S. Batsouli et al., Phys. Lett. B 557 (2003) 26.

14. ISMD’05, Kromeriz, Aug 09  15, 2005 14 AuAu 200 GeV min.bias S/B = 1 : 1000 Counts D 0 - Spectra D 0  K +  d+Au : no flow Au+Au: charm-quark flow,  = 0.4c ?  Differences in spectra: 50%  Need precise (direct) measurement  TPC (+TOF): - large combinatorial backgrd. - large syst. uncertainties (30%)  Use decay topology Data: STAR, Phys. Rev. Lett. 94, 062301. Also: H. van Hees and R. Rapp, Phys. Rev C71, 034907.

15. ISMD’05, Kromeriz, Aug 09  15, 2005 15 STAR Detector Upgrade D 0  K +  c  = 123  m Measure decay vertex,   50  m enhance S/B by factor 100  precise heavy-flavor measurements ! Full Barrel MRPC - TOF Heavy Flavor Tracker

16. ISMD’05, Kromeriz, Aug 09  15, 2005 16 Summary  Multi-strange hadrons  and  flow  Partonic collectivity  Measure spectra, elliptic flow and yields of D 0, D , D + s,   C  Probe (u,d,s)-quark thermalization  STAR upgrade TOF +  Vertex