1. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 1 D – D Correlations as a Sensitive Probe of Light – quark Thermalization 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.

2. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 2 Outline 1)Introduction 2)Strange  quark flow: partonic collectivity 3)Heavy  quark collectivity 4)Summary

3. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 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 and LHC (?) Probe thermalization using heavy-quarks

4. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 4 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   Temperature Plot: Steffen A. Bass, Duke University Heavy-Flavor     , K, p T ch = 160-170 MeV T fo = 100 MeV

5. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 5 1) Compared to , K, and p, multi- strange particles ,  are found at lower but higher T ~ T ch  Collectivity prior to hadronization 2) Sudden single freeze-out*: Resonance decays lower T fo for ( , K, p)  Collectivity prior to hadronization  take snapshot at early (partonic?) stage  take snapshot at early (partonic?) stage Kinetic Freeze-out Data: STAR, Data: STAR, Nucl. Phys. A715, 129c(2003). *A. Baran, W. Broniowski and W. Florkowski; nucl-th/0305075

6. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 6 Anisotropy Parameter v 2 y x pypy pxpx coordinate-space-anisotropy  momentum-space-anisotropy Initial/final conditions, EoS, degrees of freedom

7. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 7 v 2 in the Low-p T Region - Minimum bias data! At low p T, model result fits mass hierarchy well! - Details do not work, need more flow in the model ! P. Huovinen, private communications, 2004

8. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 8 v 2 of Multi-strange Hadrons ,  ,  and   do flow = Strangeness flows  partonic collectivity at RHIC ! * Inconsistencies in current hydro calculations STAR Preliminary, QM05 conference

9. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 9 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). ….

10. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 10 Quark Masses X. Zhu, M. Bleicher, K.S., H. Stoecker, N. Xu, et al., hep-ph/0604178, subm. to PRL.  Symmetry is broken:  EW Higss mass  QCD dynamical mass  In QGP, c- and b-quark stay heavy  c- and b-quark good probe for medium created at RHIC/LHC  If heavy quarks flow:  frequent interactions among all quarks  light quarks (u,d,s) likely to be thermalized

11. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 11 The key point is to determine Heavy-Flavor Collectivity D 0, D , D + s,  + C, J/ , …

12. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 12 Non-photonic electron v 2 c (b)  e + X  Large syst. uncertainties due to large background  charm collective flow at p t < 2GeV/c  v 2 (e) favors non-zero v 2 (c) at p T (e)<2 GeV/c. V. Greco et al. PLB 595(2004)202 B. Zhang et al. nucl-th/0502056

13. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 13 J/  Enhancement at RHIC(LHC)  Statistical hadronization  strong centrality dependence of J\  yield at LHC  Need total charm yields !  Measure D 0, D ±,  c  Probe deconfinement and thermalization Calculations: P. Braun Munzinger, K. Redlich, and J. Stachel, nucl-th/0304013.  cc

14. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 14 J/  yield vs Centrality Statistical Hadronization Synopsis: - Complete screening of primordial J/ψ’s - J/ψ’s regenerated at chemical freezout from thermalized c-cbars Disagrees with STAR Barely touches PHENIX data Large uncertainties in total c-cbar yield  need precise reference for total charm ! [1] A. Andronic et al., Phys.Lett. B571 (2003) 36-44 [3] STAR, Phys. Rev. Lett. 94 (2005) 062301 [2] PHENIX, Phys.Rev.Lett. 96 (2006) 032001 STAR Preliminary

15. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 15 Multiply Heavy-flavored Hadrons F. Becattini, Phys. Rev. Lett. 95, 022301 (2005); P. Braun Munzinger, K. 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 @ LHC  QGP ! Quarks and gluons  hadrons Pb+Pb  ccc / D : p+p x1000

16. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 16  D  Meson Pair Correlations Pythia Calcs.: H. Woehri, priv. comm. Hadronic Transport Model: E.L. Bratkovskaya et al., PRC 71 (2005) 044901.  ccbar pair production: DDbar pairs are correlated !  Here:  correlation  If charm equilibrates  correlations vanish !  Influence of hadronic scattering (small) ? ccbar

17. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 17 Pythia Predictions  p +p : Pyhtia predicts DDbar – correlations  Stronger at larger p T  Back-to-back corr. Modified in QGP ? X. Zhu, M. Bleicher, K.S., H. Stoecker, N. Xu, et al., hep-ph/0604178, subm. to PRL.

18. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 18 c  cbar in QGP  Langevin approach - describe c-quarks in QGP - a: momentum-space diffusion - fragment c  hadrons  At small p T corr. smear out  At large p T corr. preserved  Heavy-quark resonances in QGP  a: increases !  Correlations vanish up to p T = 3 GeV ! X. Zhu, M. Bleicher, K.S., H. Stoecker, N. Xu, et al., hep-ph/0604178, subm. to PRL. RHICLHC

19. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 19 Hadronic Re-scattering  Hadronic re-scattering can not completely wash out DD-correlations  Frequent partonic re-scattering needed  light quark thermalization ! X. Zhu, M. Bleicher, K.S., H. Stoecker, N. Xu, et al., hep-ph/0604178, subm. to PRL.

20. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 20 Summary  Strange – quarks flow , , and   Deconfinement at RHIC  Heavy – quarks (c, b) are precise probes  Measure D  Dbar correlations  Probe (u,d,s)-quark thermalization  Deconfinement + Thermalization = QGP !

21. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 21 STAR @ RHIC / ALICE @ LHC e.g.: D 0  K +  c  = 123  m Measure precisely secondary decay vertex Use silicon pixel technology  precise heavy-flavor measurements at RHIC and LHC ! Heavy Flavor Tracker

22. ISMD, Paraty, Brazil, Sep 2  Sep 8, 2006 Kai Schweda 22 Two Different Ways to Probe Bulk Use high p T as probeProbe the bulk responsePartons lose energy in medium Response of medium to pressure Measure nuclear modification factor R AA Measure elliptic flow v 2 Partonic energy loss dE/dx, gluon density Partonic equation of state EoS  It’s all about interactions  Interactions  collectivity (e.g. flow)  Frequent interactions  Thermalization