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Heavy quark ”Energy loss" and ”Flow" in a QCD matter

Heavy quark ”Energy loss" and ”Flow" in a QCD matter. KPS 2007 Fall meeting 한국물리학회 2007 가을 October, 2007 Jeju Korea. DongJo,Kim Jyväskylä University, Finland. Outline. Heavy Ion Physics Centrality(Glauber model, R AA Flow (v 2 )) Discoveries on light quark sector …..

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Heavy quark ”Energy loss" and ”Flow" in a QCD matter

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  1. Heavy quark ”Energy loss" and ”Flow" in a QCD matter KPS 2007 Fall meeting 한국물리학회 2007 가을 October, 2007 Jeju Korea DongJo,Kim Jyväskylä University, Finland

  2. Outline Heavy Ion Physics Centrality(Glauber model, RAA Flow (v2)) Discoveries on light quark sector ….. Heavy quark measurement ( RAA, v2 ) Theoretical guidelines Summary

  3. SPS era: Smoking gun wanted RHIC era: sQGP discovered 8x LHC era: ? 2008 LHC pp s14 TeV 27x 2008 LHC AA s5.5 TeV CERN 11x 2000 RHIC s200 GeV USA 4x 90s SPS s17 GeV CERN 80s AGS s4 GeV USA Relativistic Heavy Ion Collider Brookhaven Nat. Lab. Long Island, USA HI - Center Of Mass Energy regimes DongJo Kim, KPS 2007 Fall

  4. Participants vs Binary collisions Participant = at least one inelastic collision Binary collision = point like scattering, optical theorem NxM DongJo Kim, KPS 2007 Fall

  5. p+p varies with impact parameter b n x m  Nbinary HI collision - Nuclear Modification Factor RAA A+A DongJo Kim, KPS 2007 Fall

  6. larger pressure gradient in plane multiple scattering less yield out more in plane Nuclear Geometry and Hydrodynamic flow RP PRL 91, 182301 DongJo Kim, KPS 2007 Fall

  7. baryons v2 mesons • v2(KET) universal for baryons • v2(KET) universal for mesons • Do we have an even more universal scaling? What are the relevent DOF’s in “Flow” ? Phys. Rev. Lett., 2007, 98, 162301 “Fine structure” of v2(pT) for different mass particles. In Ideal “hydro” picture: v2(pT) v2(KET) DongJo Kim, KPS 2007 Fall

  8. quarks dVPS Phys.Rev.Lett.91:092301,2003 Elliptic anisotropy from the recombination Azimuthal prob. density distrib. of the quark field DongJo Kim, KPS 2007 Fall

  9. 0.1 0.05 0 v2/nq The “Flow” Knows Quarks • Assumption: • all bulk particles are coming from recombination of flowing partons baryons v2 v2 mesons Discovery of universal scaling: • flow parameters scaled by quark content nq resolves meson-baryon separation of final state hadrons. Works for strange and even charm quarks. • strongly suggests the early thermalization and quark degree of freedom. DongJo Kim, KPS 2007 Fall

  10. (η = 0) PHENIX Preliminary Phys. Rev. Lett. 88, 192303 (2002) How to measure Heavy Flavor ? • STAR • Direct D mesons hadronic decay channels in d+Au • D0Kπ • D±Kππ • D*±D0 π • Single electron measurements in p+p, d+Au • PHENIX • Single electron measurements in p+p, d+Au, Au+Au , y~0sNN = 130,200,62.4 GeV • Single muon measurements in p+p, d+Au ,1<|y|<2 sNN = 200 GeV • Experimentally observe the decay products of Heavy Flavor particles (e.g. D-mesons) • Hadronic decay channels DKp, D0p+ p- p0 • Semi-leptonic decays De(m) K ne DongJo Kim, KPS 2007 Fall

  11. How to measure Heavy Flavor?  Charm/Bottomelectrons Signal/Background Run04: X=0.4%, Radiation length • S/B > 1 for pT > 1 GeV/c Run02: X=1.3% We use two different methods to determine the non-photonic electron contribution (Inclusive = photonic + non-photonic ) • Cocktail subtraction – calculation of “photonic” electron background from all known sources • Converter subtraction– extraction of “photonic” electron background by special run with additional • converter (X = 1.7%) DongJo Kim, KPS 2007 Fall

  12. eID @ RICH Electrons Hadronic background Systematic on the measurement Signal/Background PRL 97(2006) 252002 • Cocktail and converter analysis agrees very well • Low pT : Converter • High pT : Cocktail • S/B > 1 for pT > 2 GeV/c E/p DongJo Kim, KPS 2007 Fall

  13. Heavy Flavor in Au+Au 200GeV • No suppression at low pT • consistent with N<coll> scaling of total charm yield • Suppression observed for pT>3.0 GeV/c, • smaller than for light quarks( RAA ~ RcharmAA). PRL. 98, 172301 (2007) DongJo Kim, KPS 2007 Fall

  14. Non-photonic electron v2 measurement • Non photonic electron v2 is given as; (1) (2) v2e ; Inclusive electron v2 =>Measure RNP = (Non-γ e) / (γ e) => Measure • v2γ.e ; Photonic electron v2 • Cocktail method (simulation)stat. advantage • Converter method (experimentally) DongJo Kim, KPS 2007 Fall

  15. Photonic e v2 determination v2 (π0) R = N X->e/ Nγe pT<3 ; π (nucl-ex/0608033) pT>3 ; π0 (PHENIX run4 prelim.) decay • photonic electron v2 • => cocktail of photonic e v2 photonic e v2 (Cocktail) • good agreement • converter method • (experimentally determined) DongJo Kim, KPS 2007 Fall

  16. Non-zero charm v2 ? (1) • Apply recombination model • Assume universal v2 (pT) for quark • simultaneous fit to v2π, v2K and v2non-γe Shape is determined with measured identified particle v2 universal v2 (pT) for quark [PRC 68 044901 Zi-wei & Denes] charm a,b ; fitting parameters DongJo Kim, KPS 2007 Fall

  17. Non-zero charm v2 ? (2) b ; charm χ2 minimum result 2σ D->e 1σ 4σ a ; u • χ2 minimum ; a = 1, b = 0.96 (χ2/ndf = 21.85/27) • Based on this recombination model, the data suggest non-zero v2 of charm quark. DongJo Kim, KPS 2007 Fall

  18. Compare with models (1) Charm quark thermal + flow (2) large cross section ; ~10 mb (3) Resonance state of D & B in sQGP (4) pQCD [Phys.Lett. B595 202-208] [PRC72,024906] [PRC73,034913] [PRB637,362] DongJo Kim, KPS 2007 Fall

  19. Overview of Theoretical Framework • pQCD (1) • Radiative energy loss ( GLV, light quarks ) • Collisional(elastic) energy loss ( additional 2x2 process ) • Still pending issues not solved ( only RAA, Charm/Bottom Ratio ) • Relative magnitude of elastic vs radiative loss channels • Non-perturbative pQCD (2) • Adding nonperturbative hadronic final state interaction effects • I.van Vite and A. Adil( Collisional dissociation, RAA ) • Van Hees ( recombination , RAA and v2 ) • AdS/CFT Related (3) • Partonic radiative transport coeff ( ) : H.Liu, K.Rajagopal,U.A. Wiedemann • Diffusion coefficient(DHQ) , RAA and v2 ) : G.D. Moore, D.Teany • W. Horowitz ( more like direct calculation according to ads/CFT ) • Double ratio ( RAA(charm)/RAA(bottom) ) • Comparison with pQCD DongJo Kim, KPS 2007 Fall

  20. Shear Viscosity(  ) to Entropy density( s ) ratio • Shear Viscosity(  ) to Entropy density( s ) ratio /s ~ 1/4 (4) • Diffusion coefficient(DHQ) , RAA and v2 ) : G.D. Moore, D.Teany • Elastic scattering and resonance excitation : Van Hees • Ads/CFT itself • Hydrodynamics DongJo Kim, KPS 2007 Fall

  21. parton light ENERGY LOSS hot and dense medium Suppress radiation in a cone of Θ < mQ/E Dead cone effect No collinear divergence M.Djordjevic PRL 94 (2004) Heavy quarks as a probe 2003 CTEQ SS - Cacciari Heavy quark mass DongJo Kim, KPS 2007 Fall

  22. S. Wicks et al., nucl-th/0512076 Elastic energy loss Partonic Energy Loss Radiative 2N processes. Final state QCD radiation as in vacuum (p+p coll) - enhanced by QCD medium. Elastic 22 LO processes Elastic E models predict significant broadening of away-side correlation peak - not seen in the data. Also various models differ significantly in radiative/elastic fraction. DongJo Kim, KPS 2007 Fall

  23. Electrons Pions Elastic energy loss is becoming important? First results indicate that the elastic energy loss may be important M. G. Mustafa, Phys.Rev.C72:014905,2005 as = .3 (1)PHENIX ,PRL. 98, 172301 (2007) (2) M. G. Mustafa, Phys.Rev.C72:014905,2005 DongJo Kim, KPS 2007 Fall

  24. QGP extent B D 25 fm 0.4 fm 1.6 fm Collisional dissociation ? (3)I. Vitev (A.Adil, I.V., hep-ph/0611109), Phys Lett B649 139-146 2007 • Fragmentation and dissociation of hadrons from heavy quarks inside the QGP DongJo Kim, KPS 2007 Fall

  25. HQ Energy Loss and Flow PRL. 98, 172301 (2007) • Two models describes strong suppression and large v2 simultaneously • Rapp and Van Hees Phys.Rev.C71:034907,2005 • Elastic scattering : small τ • DHQ × 2πT ~ 4 - 6 • Moore and Teaney Phys.Rev.C71:064904,2005 • DHQ × 2πT = 3~12 • Recall +p = T s at B=0 • This then gives /s ~(1.5-3)/4 • Within factor of 2 of conjectured bound Phys.Rev.D74,0850012,2006 DongJo Kim, KPS 2007 Fall

  26. Viscosity  then defined as . In the standard picture • reflects the transport properties of multi-particle system. • Small viscosity→ Large cross sections • Large cross sections →Strong couplings • Strong couplings → perturbation theory difficult ! • String theory approach: • Strongly interacting matter  AdS/CFT duality  • (Phys. Rev. Lett., 2005, 94, 111601) • What can we learn from the data ? Is the quark matter really perfect fluid? Ideal(perfect, inviscid) fluid  =0 DongJo Kim, KPS 2007 Fall

  27. Universal /s Minimum of in units of P.Kovtun, D.Son, A.S., hep-th/0309213, hep-th/0405231 DongJo Kim, KPS 2007 Fall

  28. (/s)min in units of ~8.8 ~25 ~23 ~ 4.2 QCD Chernai, Kapusta, McLerran, nucl-th/0604032 a trapped Fermi gas T.Schafer, cond-mat/0701251 DongJo Kim, KPS 2007 Fall

  29. Phys. Rev. Lett., 2007, 98, 092301 Phys. Rev., 2003, C68, 034913 Viscosity from the data at RHIC • Temperature • T=160 MeV • Mean free path (transport sim.) • f=0.30.03 fm • Speed of sound • cs=0.350.05 DongJo Kim, KPS 2007 Fall

  30. AdS/CFT and pQCD at LHC Double ratio of charm and bottom quark suppression promising window for AdS/CFT models. W.Horowitz Gyulassy arXiv:0706.2336 DongJo Kim, KPS 2007 Fall

  31. Summary • Electron RAA & v2 mainly from charm decay @ s = 200 GeV in Au+Au collisions at RHIC-PHENIX • Similar suppression as light quarks at high pT • Large v2 is observed • Charm quark strongly coupled to the matter • Model comparison suggests • Small τ and/or DHQ are required • η/s is very small, near quantum bound. • AdS/CFT will help the problems in pQCD or something else we will find ? • Direct measurement of Charm/Bottom with PHENIX upgrade and D/B Factory at LHC DongJo Kim, KPS 2007 Fall

  32. AdS/CFT Correspondence hep-th/0605158 Put FD/String too here DongJo Kim, KPS 2007 Fall

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