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Heavy - Flavor (c,b) Collectivity at RHIC and LHC

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. Outline. Introduction Multi-strange baryons elliptic flow Heavy-quark Collectivity

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Heavy - Flavor (c,b) Collectivity at RHIC and LHC

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  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.

  2. Outline • Introduction • Multi-strange baryons elliptic flow • Heavy-quark Collectivity • Summary

  3. Quark Gluon Plasma Source: Michael Turner, National Geographic (1996) • Quark Gluon Plasma: • Deconfined and • thermalized state of quarks and gluons •  Study partonic EOS at RHIC(?) Probe thermalization using heavy-quarks

  4. Phase Diagram

  5. Heavy Ion Collisions Heavy-Flavor X, W, f D++, L* p, K, p Time  1) Initial condition: 2) System evolves: 3) Bulk freeze-out: - baryon transfer - parton/hadron expansion - hadronic dof - ET production - interaction cease - Partonic dof Tth, <bT> Plot: Steffen A. Bass, Duke University

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

  7. STAR Au + Au Collisions at RHIC Peripheral Event (real-time Level 3)

  8. STAR Au + Au Collisions at RHIC Mid-Central Event (real-time Level 3)

  9. STAR Au + Au Collisions at RHIC Central Event (real-time Level 3)

  10. Particle Identification Reconstruct multi-strange resonances in 2p acceptance of STAR!

  11. Pressure, Flow, … • Thermodynamic identity • – entropy p – pressure U – energy V – volume t = kBT, thermal energy per dof • In A+A collisions, interactions among constituentsand density distribution lead to: pressure gradient  collective flow • number of degrees of freedom (dof) • Equation of State (EOS) • cumulative – partonic + hadronic

  12. Kinetic Freeze-out at RHIC 1) Compared to p, K, and p, multi-strange particles ,  are found at lower <T> but higher T ~ Tch  Collectivity prior to hadronization 2) Sudden single freeze-out*: Resonance decays lower Tfo for (p, K, p)  Collectivity prior to hadronization Partonic Collectivity ? STAR Preliminary  Disentangle collective flow (bT) and random walk (T) Data: STAR preliminary Au+Au@200GeV: Nucl. Phys. A715, 129c(2003). *A. Baran, W. Broniowski and W. Florkowski; nucl-th/0305075

  13. Anisotropy Parameter v2 coordinate-space-anisotropy  momentum-space-anisotropy y py px x Initial/final conditions, EoS, degrees of freedom

  14. v2 in the Low-pT Region P. Huovinen, private communications, 2004 • Minimum bias data! At low pT, model result fits mass hierarchy well! • - Details does not work, need more flow in the model!

  15. Collectivity, Deconfinement at RHIC - v2, spectra of light hadrons and multi-strange hadrons - scaling with the number of constituent quarks At RHIC, it seems we have:  Partonic Collectivity • Deconfinement  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). • ….

  16. Partonic Collectivity at RHIC • 1) Copiously produced hadrons freeze-out: • Tfo = 100 MeV, T = 0.6 (c) > T(SPS) • 2)Multi-strange hadrons freeze-out: • Tfo = 160-170 MeV (~ Tch), T = 0.4 (c) • 3)Multi-strange v2: • Multi-strange hadrons  and  do flow! • 4) Constituent Quark scaling: • Seems to work for v2 and RAA (RCP) • Deconfinement & • Partonic (u,d,s) Collectivity!

  17. Heavy-Flavor Quarks • 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 106 105 104 103 102 10 1 Mass (MeV/c2) Plot: B. Mueller, nucl-th/0404015. Plot: B. Mueller, nucl-th/0404015.

  18. Charm-quark Elliptic Flow • Coalescence approach • AMPT transport model V. Greco et al., PLB 595(2004)202 B. Zhang et al., nucl-th/0502056 Large X-sec needed to reach large v2 → Charm quark flows → Indication of light flavor thermal equilibrium! Theoretical justification of the large cross section?

  19. The key point is to determine Heavy-Flavor Collectivity

  20. Non-photonic electron v2 c (b)  e + X V. Greco et al. PLB 595(2004)202 B. Zhang et al. nucl-th/0502056 • Large syst. uncertainties due to large background • Experimental data do not agree at 2<pT(e)<5 GeV/c! • v2(e) favors non-zero v2(c) at pT(e)<2 GeV/c.

  21. D0 Reconstruction in STAR • D0 p + K, BR = 3.8%, ct = 124mm • calculate invariant mass in p + K system • Peak around 1.86 GeV/c2 • Large combinatorial background •  Large stat. and syst. uncertainties • Need precise track information ! • Need precise pointing device ! TPC only Central Au + Au collisions in STAR

  22. STAR Detector Upgrade Full Barrel MRPC - TOF Heavy Flavor Tracker • D0 K + p, ct = 123mm • Measure decay vertex, s 50mm • enhance S/B by factor 100 •  precise heavy-flavor measurements ! Active Pixel Sensors: M. Winter et al., IReS/LEPSI, Strasbourg.

  23. Flow Measurements • Au + Au, 50M central events • D0 K + p • Expected statistical uncertainties small • Probe charm quark flow ! • Also: Measure Ds f + p D0 simulations: A. Shabetai D0 v2-predictions: D. Molnar, J. Phys. G31, S421.

  24. The Alice Detector @ LHC • TPC: main tracking device • ITS: high spatial resolution • TRD: good electron PID (high pion rejection) • ToF: extend PID to large pT

  25. ALICE @ LHC : D0 K-p+ • Pb + Pb central, 1st year • D0 K + p • Expected stat. + syst. uncertainties small • Probe heavy-flavor flow ! |y| < 1 and pt > 1 GeV/c Other (possible?) channels: Lc pKp (BR ~ 5%) Xc  LK0, WK+ D0 simulations: A. Dainese, nucl-ex/0510082.

  26. J/y Enhancement at LHC • Statistical hadronization  strong centrality dependence of J\y yield at LHC • Need total charm yields ! • Measure D0, D±, Lc, Xc • Probe deconfinement and thermalization Calculations:P. Braun Munzinger, C. Redlich,and J. Stachel, nucl-th/0304013.

  27. Multiply Heavy-flavored Hadrons • Statistical hadronization- de-confined heavy-quarks • equilibrated heavy-quarks •  Enhancement up to x1000 ! • Measure Xcc, Wcc, Bc, (Wccc) • Need total charm yields • Probe deconfinement and thermalization • QGP ! Quarks and gluons  hadrons Pb+Pb Wccc / D : p+p x1000 F. Becattini, Phys. Rev. Lett. 95, 022301 (2005); P. Braun Munzinger, C. Redlich, and J. Stachel, nucl-th/0304013.

  28. Summary • Multi-strange hadrons  and  flow Partonic collectivity at RHIC Deconfinement at RHIC • Measure spectra, elliptic flow and yields of D0, D, D+s, L+C, J/y, B± Probe (u,d,s)-quark thermalization • ALICE: TPC + mVertex + TRD (+ToF)

  29. Building Blocks of Matter • Elementary particles – microscopic laws:- Electroweak force- Hunt for theStrong force-Gravitation • Masses are free parameters ! • Origin of Mass ?

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