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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 X and W elliptic flow

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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 X and W elliptic flow • Heavy-quark (b,c) 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 in high energy nuclear collisions(?) Probe thermalization using heavy-quarks

  4. 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

  5. Kinetic Freeze-out at RHIC • p,K and p change smoothly from peripheral to central collisions. • At the most central collisions, <bT> reaches 0.6c. • Multi-strange particles f, W are found at higher T and lower <bT> • Sensitive to early partonic stage! • What about v2 ? 4)Single sudden freeze-out*: all collectivity from partonic stage! • STAR: NPA715, 458c(03); PRL 92, 112301(04); 92, 182301(04). *A. Baran, W. Broniowski and W. Florkowski; nucl-th/0305075.  Disentangle collective flow (bT) and random walk (T).

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

  7. Collectivity, Deconfinement at RHIC - v2, spectra of light hadrons and multi-strange hadrons - scaling with the number of constituent quarks At RHIC, I believe we have:  Partonic Collectivity • Deconfinement  Thermalization ? • PHENIX: PRL91, 182301(03) • STAR: PRL92, 052302(04), PRL95, 122301(05). • S. Voloshin, NPA715, 379(03) • Models: Greco et al, PRC68, 034904(03) • X. Dong, et al., Phys. Lett. B597, 328(04).

  8. Heavy-Flavor Quarks • Symmetry is broken: QCD dynamical mass EW Higgs mass • Even in a QGP, charm and beauty quark-mass heavy ! • 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.

  9. Charm-quark Elliptic Flow • Coalescence approach • AMPT transport model B. Zhang et al.,PRC 72(2005) 024906. V. Greco et al., PLB595(2004)202. D = (cu) • Heavy-quark collective flow observable in D-meson v2 • Large partonic cross sections needed Frequent interactions • Challenge to theory ?

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

  11. 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) suggests non-zero v2(c) at pT(e)<2 GeV/c.

  12. Heavy-flavor Energy Loss Heavy-flavor decay electrons: Probe interaction with medium  Induced gluon radiation only  Plus elastic collisions  Better agreement with data • Start understanding heavy flavor interaction with the medium ! • Disentangle b,c by direct reconstruction of B at LHC ! Calculations: M. Djordjevic et al.

  13. Heavy-Flavor in ALICE • TPC: main tracking device • ITS: high spatial resolution, D,B decay vertex • TRD: good electron PID (high pion rejection), J/y, , B,D  e • ToF: extend PID to large pT

  14. Heavy-Flavor in ALICE : 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.

  15. 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, K. Redlich,and J. Stachel, nucl-th/0304013.

  16. 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, K. Redlich, and J. Stachel, nucl-th/0304013.

  17. 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

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