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Heavy quark ”Energy loss" and ”Flow" in a QCD matter DongJo Kim, Jan Rak Jyväskylä University, Finland Lecture 16.

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Presentation on theme: "Heavy quark ”Energy loss" and ”Flow" in a QCD matter DongJo Kim, Jan Rak Jyväskylä University, Finland Lecture 16."— Presentation transcript:

1 Heavy quark ”Energy loss" and ”Flow" in a QCD matter DongJo Kim, Jan Rak Jyväskylä University, Finland Lecture 16

2 Oct-18-2007DongJo Kim, KPS 2007 Fall1 HI collision - Nuclear Modification Factor R AA A+A n x m   N binary  varies with impact parameter b p+p

3 Oct-18-2007DongJo Kim, KPS 2007 Fall2 Nuclear Geometry and Hydrodynamic flow  RP multiple scattering larger pressure gradient in plane less yield out more in plane less yield out more in plane Coordinate space Momentum space Initial Later PRL 91, 182301

4 Oct-18-2007DongJo Kim, KPS 2007 Fall3 v2v2 0.1 0.05 0 v 2 /n q The “Flow” Knows Quarks Assumption: all bulk particles are coming from recombination of flowing partons Discovery of universal scaling :  flow parameters scaled by quark content n q 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. v2v2 baryons mesons

5 Oct-18-2007DongJo Kim, KPS 2007 Fall4 PHENIX –Single electron measurements in p+p, d+Au, Au+Au, y~0  s NN = 130,200,62.4 GeV –Single muon measurements in p+p, d+Au,1<|y|<2  s NN = 200 GeV STAR –Direct D mesons hadronic decay channels in d+Au D 0  K π D ±  K ππ D* ±  D 0 π –Single electron measurements in p+p, d+Au Phys. Rev. Lett. 88, 192303 (2002) How to measure Heavy Flavor ?  Experimentally observe the decay products of Heavy Flavor particles (e.g. D- mesons) –Hadronic decay channels D  K  D 0       0 –Semi-leptonic decays D  e(  ) K  e MesonD ±,D 0 Mass1869(1865) GeV BR D 0 --> K +  - (3.85 ± 0.10) % BR D --> e + +X17.2(6.7) % BR D -->  +  +X 6.6 % PHENIX Preliminary (η = 0)

6 Oct-18-2007DongJo Kim, KPS 2007 Fall5  S/B > 1 for p T > 1 GeV/c Run04: X=0.4%, Radiation length Run02: X=1.3% Signal/Background 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%) 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%) How to measure Heavy Flavor?  Charm/Bottom  electrons

7 Oct-18-2007DongJo Kim, KPS 2007 Fall6 Systematic on the measurement Cocktail and converter analysis agrees very well Low pT : Converter High pT : Cocktail S/B > 1 for p T > 2 GeV/c PRL 97(2006) 252002 eID @ RICH Hadronic background Electrons E/p Signal/Background

8 Oct-18-2007DongJo Kim, KPS 2007 Fall7 Heavy Flavor in Au+Au 200GeV  No suppression at low p T consistent with N scaling of total charm yield  Suppression observed for p T >3.0 GeV/c, smaller than for light quarks( R  AA ~ R charm AA ). PRL. 98, 172301 (2007)

9 Oct-18-2007DongJo Kim, KPS 2007 Fall8 Non-photonic electron v 2 measurement  Non photonic electron v 2 is given as; v 2 γ.e ; Photonic electron v 2  Cocktail method (simulation) stat. advantage  Converter method (experimentally) v 2 e ; Inclusive electron v 2 => Measure R NP = (Non-γ e) / (γ e) => Measure (1) (2)

10 Oct-18-2007DongJo Kim, KPS 2007 Fall9 Photonic e v 2 determination  good agreement converter method (experimentally determined)  photonic electron v 2 => cocktail of photonic e v 2 R = N X->e / N γe photonic e v 2 (Cocktail) decay v 2 (π 0 ) pT<3 ; π (nucl-ex/0608033) pT>3 ; π 0 (PHENIX run4 prelim.)

11 Oct-18-2007DongJo Kim, KPS 2007 Fall10 Non-zero charm v 2 ? (1)  Apply recombination model  Assume universal v 2 (p T ) for quark  simultaneous fit to v 2 π, v 2 K and v 2 non-γe [PRC 68 044901 Zi-wei & Denes] charm Shape is determined with measured identified particle v 2 universal v 2 (p T ) for quark a,b ; fitting parameters

12 Oct-18-2007DongJo Kim, KPS 2007 Fall11 Non-zero charm v 2 ? (2)  χ 2 minimum ; a = 1, b = 0.96 (χ 2 /ndf = 21.85/27)  Based on this recombination model, the data suggest non-zero v 2 of charm quark. 2σ 4σ 1σ b ; charm a ; u χ 2 minimum result D->e

13 Oct-18-2007DongJo Kim, KPS 2007 Fall12 Compare with models [PRB637,362] (1) Charm quark thermal + flow (2) large cross section ; ~10 mb (3) Resonance state of D & B in sQGP (4) pQCD [PRC72,024906] [PRC73,034913] [Phys.Lett. B595 202-208 ]

14 Oct-18-2007DongJo Kim, KPS 2007 Fall13 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 R AA, 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, R AA )  Van Hees ( recombination, R AA and v 2 )  AdS/CFT Related (3)  Partonic radiative transport coeff ( ) : H.Liu, K.Rajagopal,U.A. Wiedemann  Diffusion coefficient(D HQ ), R AA and v 2 ) : G.D. Moore, D.Teany  W. Horowitz ( more like direct calculation according to ads/CFT )  Double ratio ( R AA (charm)/R AA (bottom) )  Comparison with pQCD

15 Oct-18-2007DongJo Kim, KPS 2007 Fall14 Shear Viscosity(  ) to Entropy density( s ) ratio  Shear Viscosity(  ) to Entropy density( s ) ratio  /s ~ 1/4  (4)  Diffusion coefficient(D HQ ), R AA and v 2 ) : G.D. Moore, D.Teany  Elastic scattering and resonance excitation : Van Hees  Ads/CFT itself  Hydrodynamics

16 Oct-18-2007DongJo Kim, KPS 2007 Fall15 2003 CTEQ SS - Cacciari Heavy quark mass Suppress radiation in a cone of Θ < m Q /E Dead cone effect No collinear divergence Heavy quarks as a probe parton hot and dense medium light M.Djordjevic PRL 94 (2004) ENERGY LOSS

17 Oct-18-2007DongJo Kim, KPS 2007 Fall16 Elastic energy loss S. Wicks et al., nucl-th/0512076 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.

18 Oct-18-2007DongJo Kim, KPS 2007 Fall17 Electrons Pions  s =.3 First results indicate that the elastic energy loss may be important M. G. Mustafa, Phys.Rev.C72:014905,2005 (1)PHENIX,PRL. 98, 172301 (2007) (2) M. G. Mustafa, Phys.Rev.C72:014905,2005 Elastic energy loss is becoming important?

19 Oct-18-2007DongJo Kim, KPS 2007 Fall18 Fragmentation and dissociation of hadrons from heavy quarks inside the QGP 25 fm 1.6 fm 0.4 fm B D QGP extent (3)I. Vitev (A.Adil, I.V., hep-ph/0611109), Phys Lett B649 139-146 2007 Collisional dissociation ?

20 Oct-18-2007DongJo Kim, KPS 2007 Fall19 HQ Energy Loss and Flow  Two models describes strong suppression and large v 2 simultaneously Rapp and Van Hees Phys.Rev.C71:034907,2005 Elastic scattering : small τ D HQ × 2πT ~ 4 - 6 Moore and Teaney Phys.Rev.C71:064904,2005 D HQ × 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 PRL. 98, 172301 (2007)

21 Oct-18-2007DongJo Kim, KPS 2007 Fall20 Is the quark matter really perfect fluid? 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 ! Ideal(perfect, inviscid) fluid   =0 String theory approach: Strongly interacting matter  AdS/CFT duality  (Phys. Rev. Lett., 2005, 94, 111601) What can we learn from the data ?

22 Oct-18-2007DongJo Kim, KPS 2007 Fall21 Universal  /s P.Kovtun, D.Son, A.S., hep-th/0309213, hep-th/0405231 Minimum of in units of

23 Oct-18-2007DongJo Kim, KPS 2007 Fall22 (  /s) min in units of T.Schafer, cond-mat/0701251 Chernai, Kapusta, McLerran, nucl-th/0604032 ~23 ~8.8 a trapped Fermi gas ~25 ~ 4.2 QCD

24 Oct-18-2007DongJo Kim, KPS 2007 Fall23 Viscosity from the data at RHIC Phys. Rev., 2003, C68, 034913 Phys. Rev. Lett., 2007, 98, 092301 Temperature T=160 MeV Mean free path (transport sim.) f =0.3  0.03 fm Speed of sound c s =0.35  0.05

25 Oct-18-2007DongJo Kim, KPS 2007 Fall24 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

26 Oct-18-2007DongJo Kim, KPS 2007 Fall25 RHIC R cb Ratio Wider distribution of AdS/CFT curves due to large n: increased sensitivity to input parameters Advantage of RHIC: lower T => higher AdS speed limits pQCD AdS/CFT pQCD AdS/CFT WH, M. Gyulassy, to be published SQM07 W.Horowitz Gyulassy arXiv:0706.2336

27 Oct-18-2007DongJo Kim, KPS 2007 Fall26 Model Inputs  AdS/CFT Drag: nontrivial mapping of QCD to SYM Mapping QCD N c to SYM is easy, but coupling is hard  S runs whereas  SYM does not:  SYM is something of an unknown constant  “Obvious”:  s =  SYM = const., T SYM = T QCD  D/2  T = 3 inspired:  s =.05  pQCD/Hydro inspired:  s =.3 (D/2  T ~ 1)  “Alternative”: = 5.5, T SYM = T QCD /3 1/4  Start loss at thermalization time  0 ; end loss at T c  WHDG convolved radiative and elastic energy loss   s =.3  WHDG radiative energy loss (similar to ASW)  = 40, 100  Use realistic, diffuse medium with Bjorken expansion  PHOBOS (dN g /dy = 1750); KLN model of CGC (dN g /dy = 2900) W.Horowitz Gyulassy arXiv:0706.2336

28 Oct-18-2007DongJo Kim, KPS 2007 Fall27 AdS/CFT Correspondence hep-th/0605158 Put FD/String too here


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