workshop on qcd and rhic physics, hefei, july 9-121 heavy flavors in high energy nuclear collisions...

Workshop on QCD and RHIC Physics, Hefei, July 9-12 1

Heavy Flavors in High Energy Nuclear CollisionsHeavy Flavors in High Energy Nuclear Collisions

ZHUANG Pengfei ZHUANG Pengfei (Tsinghua University, Beijing)(Tsinghua University, Beijing)

● ● J/Psi Suppression and RegenerationJ/Psi Suppression and Regeneration ● ● D Meson Correlation and Collective FlowD Meson Correlation and Collective Flow

I thank Jorg Hufner (Heidelberg), XU Nu (LBNL) and YAN Li, ZHU Xianglei (Tsinghua)I thank Jorg Hufner (Heidelberg), XU Nu (LBNL) and YAN Li, ZHU Xianglei (Tsinghua)


●●heavy quarks are produced only in the initial impact, and no extra pheavy quarks are produced only in the initial impact, and no extra production in the later evolutionroduction in the later evolution a probe of early thermalization and a probe oa probe of early thermalization and a probe of QGP f QGP

●●production via pQCD processproduction via pQCD process rather solid groundrather solid ground

importance of heavy quarksimportance of heavy quarks

B.Mueller, nucl-th/0404015B.Mueller, nucl-th/0404015


● ● both both initial production and regeneration initial production and regeneration ● ● both normal suppression and anomalous suppressionboth normal suppression and anomalous suppression

J/Psi motion in heavy ion collisionsJ/Psi motion in heavy ion collisions

Matsui and Satz PLB178, 416(1986): Matsui and Satz PLB178, 416(1986): J/Psi suppression as a signature of QGP formation in HIJ/Psi suppression as a signature of QGP formation in HI


normal suppressionnormal suppression

mechanism: multi-scattering between J/psi and spectator nucleonsmechanism: multi-scattering between J/psi and spectator nucleons R.Vogt, Phys.Rept.310, 197(1999) R.Vogt, Phys.Rept.310, 197(1999) C.Gerschel, J.Hufner, Annu.Rev.Nucl.Part.Sci. 49, 225(1999)C.Gerschel, J.Hufner, Annu.Rev.Nucl.Part.Sci. 49, 225(1999)

6.5 1.0 mbabs

conclusion:conclusion: nuclenuclear absorption can well explain the J/psi yield in p-A and light nuclear car absorption can well explain the J/psi yield in p-A and light nuclear collisions at SPS energy !ollisions at SPS energy !

NA38NA38


anomalous suppression Ianomalous suppression I

anomalous suppression in heavy ion collisionsanomalous suppression in heavy ion collisions

model 1: Debye screeningmodel 1: Debye screening (Matsui & Satz, 1986) (Matsui & Satz, 1986)

NA38NA38

Kaczmarek et al., hep-lat/0312015Kaczmarek et al., hep-lat/0312015

charmonium dissociation temperature charmonium dissociation temperature (K(Karsch, Kharzeev, Satz, PLB637, 75(2006)arsch, Kharzeev, Satz, PLB637, 75(2006)

at T=0at T=0

at Tat T≠ 0≠ 0

Asakawa & Hatsuda, 2004Asakawa & Hatsuda, 2004


anomalous suppression IIanomalous suppression II

model 3: comover interaction model 3: comover interaction (Capella, Feireiro, Kaidalov, PRL85, 2080(2000)(Capella, Feireiro, Kaidalov, PRL85, 2080(2000)

model 2: threshold model model 2: threshold model (Blaizot, Dinh, Ollitrault, PRL85, 4010(2000)(Blaizot, Dinh, Ollitrault, PRL85, 4010(2000)

dynamic processes:

/J meson D D


regeneration Iregeneration I

there are about 10 pairs of c quarks in a central Au-Au collision at RHIC energy and more there are about 10 pairs of c quarks in a central Au-Au collision at RHIC energy and more than 100 pairs at LHC energythan 100 pairs at LHC energy very important J/\psi regeneration at high energies:very important J/\psi regeneration at high energies: in QGPin QGP

in hadron gasin hadron gas

the competition between J/\psi suppression and regeneration leads to the question:the competition between J/\psi suppression and regeneration leads to the question: J/\p J/\psi suppression or enhancement at high energies?si suppression or enhancement at high energies?

model 1: sudden production model 1: sudden production (Andronic, PBM, Redlich, Stachel, NPA789, 334(2007): (Andronic, PBM, Redlich, Stachel, NPA789, 334(2007): J/\psi’s are statistically produced at T=Tc, J/\psi’s are statistically produced at T=Tc, no initial production no initial production

mesons

suppression at RHIC, suppression at RHIC, no clear enhancement at no clear enhancement at LHCLHC

/c c J g


regeneration IIregeneration II

model 2: continuous production in QGP model 2: continuous production in QGP (Thews, Mangano, PRC73, 014904(2006): (Thews, Mangano, PRC73, 014904(2006): J/\psi’s are continuously prJ/\psi’s are continuously produced in the whole QGP region including anomalous suppreoduced in the whole QGP region including anomalous suppression no initial production ssion no initial production

* perturbative calculation with nonrelativistic Coulomb potential (Peskin, Bhanot, NPB156, 365(1979) * detailed balance

model 3: two-component model model 3: two-component model (Grandcham(Grandchamp, Rapp, Brown, PRL92, 212301(2004): p, Rapp, Brown, PRL92, 212301(2004): ininitial production + sudden regenerationitial production + sudden regeneration

the yield in central collisions is the yield in central collisions is controlled by the regeneration !controlled by the regeneration !


necessary regeneration ?necessary regeneration ?

heavy quark potential heavy quark potential (Young, Shuryak, 2008):(Young, Shuryak, 2008):

V = U, F=U-TSV = U, F=U-TS

Schroedinger equation:Schroedinger equation: J/psi dissociation temperature Td = 2.7 Tc > maximum T at RHIC.J/psi dissociation temperature Td = 2.7 Tc > maximum T at RHIC.

there is no big difference between SPS and RHIC ! there is no big difference between SPS and RHIC ! This explains why there is no big difference between suppres This explains why there is no big difference between suppressions at SPS and at RHIC. sions at SPS and at RHIC.

regeneration looks not necessary !?regeneration looks not necessary !?


transport model transport model (Hufner and Zhuang, PLB559, 193(2003): (Hufner and Zhuang, PLB559, 193(2003): transport equation for J/\psi and hydrodynamics for QGPtransport equation for J/\psi and hydrodynamics for QGP

leakage

for J/\psi yield, almost all the models – with and without the assumption of for J/\psi yield, almost all the models – with and without the assumption of QGP and with and without regeneration mechanism – describe the observQGP and with and without regeneration mechanism – describe the observed suppression, after at least one parameter is adjusted.ed suppression, after at least one parameter is adjusted.

the transverse momentum distribution which depends more directly on ththe transverse momentum distribution which depends more directly on the production mechanism may contain additional information about the nate production mechanism may contain additional information about the nature of the medium and J/\psi and may help to distinguish between differenure of the medium and J/\psi and may help to distinguish between different scenarios.t scenarios.

transverse momentum Itransverse momentum I

anomalous suppression

regeneration

comover mechanismcomover mechanism

no regeneration at SPSno regeneration at SPS

very important leakage effect !very important leakage effect !

direct production & nuclear absorption as initial condition


general solution of the transport equation at RHIC and LHC:general solution of the transport equation at RHIC and LHC:

transverse momentum IItransverse momentum II

Yan, Xu, Zhuang, PRL97, 232301(2006)Yan, Xu, Zhuang, PRL97, 232301(2006)


dominant regeneration at LHCdominant regeneration at LHC

rapidity dependence, a possible evidence of regeneration at RHIC !rapidity dependence, a possible evidence of regeneration at RHIC !

PHENIX, PRL98, 232301(2007)PHENIX, PRL98, 232301(2007)

Liu, Xu, Zhuang: Liu, Xu, Zhuang: the calculation in transport the calculation in transport model is in progressmodel is in progress

while both initial production and regeneration while both initial production and regeneration are important at RHIC, the J/psi yield at LHC iare important at RHIC, the J/psi yield at LHC is characterized by the regeneration only!s characterized by the regeneration only!

* enhanced R_AA at LHC * enhanced R_AA at LHC * large * large V2 at LHCV2 at LHC


near side correlation at LHCnear side correlation at LHCDD

we take drag coefficient to we take drag coefficient to be a parameter charactering be a parameter charactering the coupling strength the coupling strength

* c quark motion in QGP:* c quark motion in QGP:

* QGP evolution: * QGP evolution: ideal hydrodynamicsideal hydrodynamics

for strongly interacting quark-gluon plasma: for strongly interacting quark-gluon plasma: ● ● at RHIC, the back-to-back correlation is washed out.at RHIC, the back-to-back correlation is washed out.● ● at LHC, c quarks are fast thermalized, the strong float LHC, c quarks are fast thermalized, the strong flow push the D and Dbar to the near side!w push the D and Dbar to the near side!

Zhu, Xu, Zhuang, PRL100, 152301(2008)Zhu, Xu, Zhuang, PRL100, 152301(2008)

large drag parameter is confirmed by R_AA and v_2 of large drag parameter is confirmed by R_AA and v_2 of non-photonic electrons non-photonic electrons (PHENEX, 200(PHENEX, 2007; Moore and Teaney, 2005; Horowitz, Gyulassy, 2007).7; Moore and Teaney, 2005; Horowitz, Gyulassy, 2007).


heavy quark thermolization heavy quark thermolization

0

32

1 1 2 2 1 1 2 2 1 22 31,2

, , | ,

1 , , | ( ) ( ) ( ),

1

0, 0

( , ) ( , ) ( , , , ) ( )(2 )

eqc c

c

cc eqc pp A B c c p u

i i iDD c q M

it i

f fv f x p bx

f x p b T x T x b g p fe

T N

p d d pd Ng f x p f x p f x p x p p p p

dp E

● ● only charm quarks (D mesons) with pt<2 GeV are thermalized only charm quarks (D mesons) with pt<2 GeV are thermalized ● ● averaged thermalization time is about 3 fm/c averaged thermalization time is about 3 fm/c

Greco, Ko, Rapp, 2004Greco, Ko, Rapp, 2004


● ● J/PsiJ/Psi RHIC: RHIC: both initial production and regeneration both initial production and regeneration

J/\psi suppression and small V2J/\psi suppression and small V2 LHC: LHC: only regeneration only regeneration

J/\psi enhancement and large V2J/\psi enhancement and large V2 FAIR: FAIR: only initial productiononly initial production very small V2very small V2 the calculation at RHIC needs a quite accurate fine-tuning between the the calculation at RHIC needs a quite accurate fine-tuning between the

initial production and regeneration, but the case atinitial production and regeneration, but the case at LHC (only LHC (only regeneration)regeneration) oror FAIR (only initial production)FAIR (only initial production) is quite clean.is quite clean.

conclusionsconclusions

● ● DDbar correlation, a signal sensitive to sQGP DDbar correlation, a signal sensitive to sQGP RHIC: RHIC: back-to-back correlation disappearsback-to-back correlation disappears LHC: LHC: near side correlationnear side correlation

● ● charm quark thermalization charm quark thermalization only charm quarks with pt<2 GeV are thermalized only charm quarks with pt<2 GeV are thermalized averaged thermalization time is about 3 fm/caveraged thermalization time is about 3 fm/c


●● medium effect on charm quark and on charmonium medium effect on charm quark and on charmonium strongly coupled QGP, chiral symmetry restoration, critical behavior, strongly coupled QGP, chiral symmetry restoration, critical behavior, mass, width, binding energy,......mass, width, binding energy,...... see Lee, arXiv:08050471 see Lee, arXiv:08050471

●● cold nuclear matter effect (initial parton rescattering) cold nuclear matter effect (initial parton rescattering) see Qiu, Vary, Zhang, PRL88, 232301(2002)see Qiu, Vary, Zhang, PRL88, 232301(2002)

outlookoutlook

●● charm quark production in QGP charm quark production in QGP see Xu, NPA697, 825(2002), Ko, this workshopsee Xu, NPA697, 825(2002), Ko, this workshop

●● charm quark potential charm quark potential between free energy F=U-TS and internal energy between free energy F=U-TS and internal energy different dissociation temperature (from Schroedinger equation)different dissociation temperature (from Schroedinger equation) see see Young, Shuryak, arXiv:0803.2866 Young, Shuryak, arXiv:0803.2866

workshop on qcd and rhic physics, hefei, july 9-121 heavy flavors in high energy nuclear collisions...

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