Medium Effects in Charmonium Transport

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Medium Effects in Charmonium Transport. Xingbo Zhao with Ralf Rapp Department of Physics and Astronomy Iowa State University Ames, USA. Purdue University, West Lafayette, Jan. 6 th 2011. Outline. charmonium transport approach charmonium equilibrium properties from lattice QCD - PowerPoint PPT Presentation

Transcript of Medium Effects in Charmonium Transport

Medium Effects in Charmonium Transport

Medium Effects in Charmonium Transport

Xingbo Zhaowith Ralf Rapp

Department of Physics and AstronomyIowa State University Ames, USA

Purdue University, West Lafayette, Jan. 6th 2011

Outlinecharmonium transport approachcharmonium equilibrium properties from lattice QCDJ/ phenomenology in heavy-ion collisions

explicit calculation of charmonium regeneration rate3-to-2 to 2-to-2 reduction

summary and outlook2Charmonium in Heavy-Ion Collisioncharmonium: a probe of QGP (deconfinement)

equilibrium properties obtained from lattice QCDfree energy between two static quarkscurrent-current correlator ( spectral function)yields measured in heavy-ion collisionscollision energy dependence (SPS, RHIC, LHC)centrality, rapidity, transverse momentum dependence

?[Matsui and Satz. 86]3Establishing the Linkkey questions:are J/ data compatible with eq. properties from lattice QCD?if yes, to what extent J/ data constrain eq. properties?

challenges:dynamically expanding fireball dissociation vs. regenerationslow chemical and kinetic equilibriumoff- equilibrium system

kinetic (transport) approach required

J/DD-J/c-c4Kinetic Approach

Boltzmann transport equation:

: dissociation rate; : regeneration rate[Zhang et al 02, Yan et al 06] integrate Boltzmann eq. over phase space rate equation:

Neq: equilibrium limit of , estimated from statistical model [Braun-Munzinger et al. 00, Gorenstein et al. 01][Thews et al 01, Grandchamp+RR 01] need microscopic input for and

key quantity determining and : binding energy, B

5Kinetic equationslQCD potentialdiss. & reg. ratesInitial conditionsExperimental observableslQCD correlator(Binding energy)Link between Lattice QCD and Exp. Data6Kinetic equationslQCD potentialdiss. & reg. ratesInitial conditionsExperimental observableslQCD correlator(Binding energy)Link between Lattice QCD and Exp. Data7Charmonium In-Medium Binding

potential model employed to evaluate

V(r)=U(r) vs. F(r)? (F=U-TS)

2 extreme cases: V=U: strong binding V=F: weak binding[Cabrera et al. 07, Riek et al. 10]

[Riek et al. 10][Petreczky et al 10]

8Kinetic equationslQCD potentialdiss. & reg. ratesInitial conditionsExperimental observableslQCD correlator(Binding energy)Link between Lattice QCD and Exp. data9In-medium Dissociation Mechanisms

[Bhanot and Peskin 79][Grandchamp and Rapp 01] gluo-dissociation is inefficient with in-medium B: with in-medium (small) B, c and inside are almost on shell on shell particle cannot absorb gluon without emission (e.g., no photoelectric effect on a free electron) gluon thermal mass further reduces the gluo-dissociation rate gluo-dissociation:quasifree dissociation:g+c+g(q)+c+ +g(q)

VS.10T and p Dependence of Quasifree Rate

gluo-dissociation is inefficient in even the strong binding scenario quasifree rate increases with both temperature and momentum dependence on both is more pronounced in the strong binding scenario11Kinetic equationslQCD potentialdiss. & reg. ratesInitial conditionsExperimental observableslQCD correlator(Binding energy)Link between Lattice QCD and Exp. Data12Kinetic equationslQCD potentialdiss.& reg. ratesInitial conditionsExperimental observableslQCD correlator(Binding energy)Link between Lattice QCD and Exp. Data13Model Spectral Functions

model spectral function = resonance + continuum at finite temperature: Z(T) reflects medium induced change of resonance strength

Tdiss=2.0Tc V=UTdiss=1.25Tc V=FZ(Tdiss)=0 in vacuum: Z(T) is determined by requiring the resulting correlator ratio consistent with lQCD results

TdissTdiss

width threshold 2mc*pole mass m 14Correlators and Spectral Functions obtained correlator ratios are compatible with lQCD results

weak binding strong binding

[Petreczky et al. 07]15Link between Lattice QCD and Exp. DataKinetic equationslQCD potentialdiss.& reg. ratesInitial conditionsExperimental observableslQCD correlator(Binding energy) a set of dissociation and regeneration rates fully compatible with lQCD has been obtainedshadowingnuclear absorptionCronin16Kinetic equationslQCD potentialdiss.& reg. ratesInitial conditionsExperimental observableslQCD correlator(Binding energy)Link between Lattice QCD and Exp. Data17Compare to data from SPS NA50 weak binding (V=F) strong binding (V=U)

incl. J/psi yieldtrans. momentum primordial production dominates in strong binding scenario

18J/ yield and at RHIC mid-y weak binding (V=F) strong binding (V=U)

larger fraction for regenerated in weak binding scenario strong binding scenario tends to better reproduce data incl. J/psi yieldtrans. momentumSee also [Thews 05],[Yan et al. 06],[Andronic et al. 07]

19RAA(pT) and v2(pT) at RHIC primordial component dominates at high pt (>5GeV) significant regeneration component at low pt formation time effect and B-feeddown enhance high pt J/ small v2(pT) for entire pT range, reg. component vanishes at high pT[Gavin and Vogt 90, Blaizot and Ollitrault 88, Karsch and Petronzio 88] weak binding (V=F) strong binding (V=U)

[Zhao and Rapp 08]20ZhuangJ/ yield and at LHC weak binding (V=F) strong binding (V=U) regeneration component dominates except for peripheral collisions RAA1000, empirical flow and hydro for time evolutionPrimordial and Regeneration Components Linearity of Boltzmann Eq. allows for decomposition of primordial and regeneration components

For primordial component we directly solve homogeneous Boltzmann Eq.For regeneration component we solve a Rate Eq. for inclusive yield and estimate its pt spectra using a locally thermal distribution boosted by medium flow.39Rate-Equation for Reg. Component

For thermal c spectra, Neq follows from charm conservation:

Non-thermal c spectra lead to less regeneration:

(Integrate over phase space) typical

[van Hees et al. 08, Riek et al. 10][Braun-Munzinger et al. 00, Gorenstein et al. 01][Grandchamp, Rapp 04][Greco et al. 03]40 follows from spectra in pp collisions with Cronin effect appliedInitial Condition and RAA is obtained from primordial production

follows from Glauber model with shadowing and nuclear absorption parameterized with an effective abs

assuming

nuclear modification factor:

Ncoll: Number of binary nucleon-nucleon collisions in AA collisionsRAA=1, if without either cold nuclear matter (shadowing, nuclear absorption, Cronin) or hot medium effects41Correlators and Spectral Functions

pole mass m(T), width (T)threshold 2mc*(T), two-point charmonium current correlation function: charmonium spectral function:

lattice QCD suggests correlator ratio ~1 up to 2-3 Tc:

[Aarts et al. 07, Datta te al 04, Jakovac et al 07]

42Initial Conditionscold nuclear matter effects included in initial conditionsnuclear shadowing: nuclear absorption:Cronin effect:

implementation for cold nuclear matter effects:nuclear shadowingnuclear absorptionCronin effect Gaussian smearing with smearing width guided by p(d)-A data

Glauber model with abs from p(d)-A data 43