2. USTC, Hefei, Nov 22, 2005 1 Heavy  Flavor (c,b) Collectivity at RHIC and LHC Kai Schweda, University of Heidelberg A. Dainese, X. Dong, J. Faivre, Y. Lu, H.G. Ritter, L. Ruan, A. Shabetai, P. Sorensen, N. Xu, H. Zhang, Y. Zhang.

3. USTC, Hefei, Nov 22, 2005 2 Outline 1)Introduction 2)Multi-strange baryons elliptic flow 3)Heavy-quark Collectivity 4)Summary

4. USTC, Hefei, Nov 22, 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

5. USTC, Hefei, Nov 22, 2005 4 Phase Diagram

6. USTC, Hefei, Nov 22, 2005 5 Heavy Ion Collisions 1) Initial condition:2) System evolves:3) Bulk freeze-out: - baryon transfer- parton/hadron expansion- hadronic dof - E T production- interaction cease - Partonic dof T th, Time  Plot: Steffen A. Bass, Duke University Heavy-Flavor     , K, p

7. USTC, Hefei, Nov 22, 2005

8. 7 The STAR Detector Coils Silicon Vertex Tracker E-M Calorimeter Trigger Barrel Time Projection Chamber Forward Time Projection Chamber Electronics Platforms Magnet

9. USTC, Hefei, Nov 22, 2005 8 Peripheral Event STAR Au + Au Collisions at RHIC (real-time Level 3)

10. USTC, Hefei, Nov 22, 2005 9 STAR Mid-Central Event Au + Au Collisions at RHIC (real-time Level 3)

11. USTC, Hefei, Nov 22, 2005 10 Au + Au Collisions at RHIC STAR Central Event (real-time Level 3)

12. USTC, Hefei, Nov 22, 2005 11 Particle Identification Reconstruct multi-strange resonances in 2  acceptance of STAR!

13. USTC, Hefei, Nov 22, 2005 12 Pressure, Flow, … Thermodynamic identity  – entropy p – pressure U – energy V – volume  = k B T, thermal energy per dof In A+A collisions, interactions among constituents and density distribution lead to: pressure gradient  collective flow  number of degrees of freedom (dof)  Equation of State (EOS)  cumulative – partonic + hadronic

14. USTC, Hefei, Nov 22, 2005 13 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 at RHIC Data: Data: STAR preliminary Au+Au@200GeV: Nucl. Phys. A715, 129c(2003). *A. Baran, W. Broniowski and W. Florkowski; nucl-th/0305075 STAR Preliminary  Disentangle collective flow (  T ) and random walk (T)

15. USTC, Hefei, Nov 22, 2005 14 Anisotropy Parameter v 2 y x pypy pxpx coordinate-space-anisotropy  momentum-space-anisotropy Initial/final conditions, EoS, degrees of freedom

16. USTC, Hefei, Nov 22, 2005 15 v 2 in the Low-p T Region P. Huovinen, private communications, 2004 - Minimum bias data! At low p T, model result fits mass hierarchy well! - Details does not work, need more flow in the model!

17. USTC, Hefei, Nov 22, 2005 16 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). ….

18. USTC, Hefei, Nov 22, 2005 17 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 !

19. USTC, Hefei, Nov 22, 2005 18 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 !  Heavy-flavor (c,b) are good probes !  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

20. USTC, Hefei, Nov 22, 2005 19 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

21. USTC, Hefei, Nov 22, 2005 20 The key point is to determine Heavy-Flavor Collectivity

22. USTC, Hefei, Nov 22, 2005 21 V. Greco et al. PLB 595(2004)202 B. Zhang et al. nucl-th/0502056 Non-photonic electron v 2 c (b)  e + X  Large syst. uncertainties due to large background  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.

23. USTC, Hefei, Nov 22, 2005 22 D 0 Reconstruction in STAR D 0   + K, BR = 3.8%, c  = 124  m calculate invariant mass in  + K system Peak around 1.86 GeV/c 2 Large combinatorial background  Large stat. and syst. uncertainties  Need precise track information !  Need precise pointing device ! Central Au + Au collisions in STAR TPC only

24. USTC, Hefei, Nov 22, 2005 23 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 Active Pixel Sensors: M. Winter et al., IReS/LEPSI, Strasbourg.

25. USTC, Hefei, Nov 22, 2005 24 Flow Measurements Au + Au, 50M central events D 0  K +  Expected statistical uncertainties small  Probe charm quark flow !  Also: Measure D s   +  D 0 simulations: A. Shabetai D 0 v 2 -predictions: D. Molnar, J. Phys. G31, S421.

26. USTC, Hefei, Nov 22, 2005 25 The Alice Detector @ LHC  TPC: main tracking device  ITS: high spatial resolution  TRD: good electron PID (high pion rejection)  ToF: extend PID to large p T

27. USTC, Hefei, Nov 22, 2005 26 ALICE @ LHC : D 0  K -  + |y| 1 GeV/c Pb + Pb central, 1 st year D 0  K +  Expected stat. + syst. uncertainties small  Probe heavy-flavor flow ! D 0 simulations: A. Dainese, nucl-ex/0510082. Other (possible?) channels:  c  pK  (BR ~ 5%)  c   K 0,  K +

28. USTC, Hefei, Nov 22, 2005 27 J/  Enhancement at LHC  Statistical hadronization  strong centrality dependence of J\  yield at LHC  Need total charm yields !  Measure D 0, D ±,  c,  c  Probe deconfinement and thermalization Calculations:P. Braun Munzinger, C. Redlich, and J. Stachel, nucl-th/0304013.

29. USTC, Hefei, Nov 22, 2005 28 Multiply Heavy-flavored Hadrons F. Becattini, Phys. Rev. Lett. 95, 022301 (2005); P. Braun Munzinger, C. Redlich, and J. Stachel, nucl-th/0304013.  Statistical hadronization - de-confined heavy-quarks - equilibrated heavy-quarks  Enhancement up to x1000 !  Measure  cc,  cc, B c, (  ccc )  Need total charm yields  Probe deconfinement and thermalization  QGP ! Quarks and gluons  hadrons Pb+Pb  ccc / D : p+p x1000

30. USTC, Hefei, Nov 22, 2005 29 Summary  Multi-strange hadrons  and  flow  Partonic collectivity at RHIC  Deconfinement at RHIC  Measure spectra, elliptic flow and yields of D 0, D , D + s,   C, J/ , B ±  Probe (u,d,s)-quark thermalization  ALICE: TPC +  Vertex + TRD (+ToF)

31. USTC, Hefei, Nov 22, 2005 30 Building Blocks of Matter  Elementary particles – microscopic laws:  Electroweak force  Hunt for the  Strong force  Gravitation  Masses are free parameters !  Origin of Mass ?