USTC, Hefei, Nov 22, 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.
USTC, Hefei, Nov 22, Outline 1)Introduction 2)Multi-strange baryons elliptic flow 3)Heavy-quark Collectivity 4)Summary
USTC, Hefei, Nov 22, 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
USTC, Hefei, Nov 22, Phase Diagram
USTC, Hefei, Nov 22, 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
USTC, Hefei, Nov 22, 2005
7 The STAR Detector Coils Silicon Vertex Tracker E-M Calorimeter Trigger Barrel Time Projection Chamber Forward Time Projection Chamber Electronics Platforms Magnet
USTC, Hefei, Nov 22, Peripheral Event STAR Au + Au Collisions at RHIC (real-time Level 3)
USTC, Hefei, Nov 22, STAR Mid-Central Event Au + Au Collisions at RHIC (real-time Level 3)
USTC, Hefei, Nov 22, Au + Au Collisions at RHIC STAR Central Event (real-time Level 3)
USTC, Hefei, Nov 22, Particle Identification Reconstruct multi-strange resonances in 2 acceptance of STAR!
USTC, Hefei, Nov 22, 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
USTC, Hefei, Nov 22, ) 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 Nucl. Phys. A715, 129c(2003). *A. Baran, W. Broniowski and W. Florkowski; nucl-th/ STAR Preliminary Disentangle collective flow ( T ) and random walk (T)
USTC, Hefei, Nov 22, Anisotropy Parameter v 2 y x pypy pxpx coordinate-space-anisotropy momentum-space-anisotropy Initial/final conditions, EoS, degrees of freedom
USTC, Hefei, Nov 22, v 2 in the Low-p T Region P. Huovinen, private communications, Minimum bias data! At low p T, model result fits mass hierarchy well! - Details does not work, need more flow in the model!
USTC, Hefei, Nov 22, 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, (03) STAR: PRL92, (04) S. Voloshin, NPA715, 379(03) Models: Greco et al, PRC68, (03) X. Dong, et al., Phys. Lett. B597, 328(04). ….
USTC, Hefei, Nov 22, 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 = 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 !
USTC, Hefei, Nov 22, Heavy-Flavor Quarks Plot: B. Mueller, nucl-th/ 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/ Mass (MeV/c 2 )
USTC, Hefei, Nov 22, 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/
USTC, Hefei, Nov 22, The key point is to determine Heavy-Flavor Collectivity
USTC, Hefei, Nov 22, V. Greco et al. PLB 595(2004)202 B. Zhang et al. nucl-th/ 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.
USTC, Hefei, Nov 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
USTC, Hefei, Nov 22, 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.
USTC, Hefei, Nov 22, 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.
USTC, Hefei, Nov 22, The Alice LHC TPC: main tracking device ITS: high spatial resolution TRD: good electron PID (high pion rejection) ToF: extend PID to large p T
USTC, Hefei, Nov 22, 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/ Other (possible?) channels: c pK (BR ~ 5%) c K 0, K +
USTC, Hefei, Nov 22, 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/
USTC, Hefei, Nov 22, Multiply Heavy-flavored Hadrons F. Becattini, Phys. Rev. Lett. 95, (2005); P. Braun Munzinger, C. Redlich, and J. Stachel, nucl-th/ 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
USTC, Hefei, Nov 22, 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)
USTC, Hefei, Nov 22, Building Blocks of Matter Elementary particles – microscopic laws: Electroweak force Hunt for the Strong force Gravitation Masses are free parameters ! Origin of Mass ?