Onset of J/Onset of J/ Melting in Quark-Melting in Quark-

Gluon Fluid at Gluon Fluid at RHICRHICTaku GunjiTaku Gunji

Center for Nuclear StudyCenter for Nuclear StudyUniversity of TokyoUniversity of Tokyo

Paper: Phys. Rev. C 76:051901 (R), 2007 Collaboration with:H. Hamagaki (CNS, Univ. of Tokyo), T. Hatsuda, T. Hirano, Y. Akamatsu (Phys. Dept. Univ. of Tokyo)

1Quark Matter 2008, Jaipur, India, 2008/2/9

OutlineOutline

• Physics Motivation • J/ suppression at RHIC• Hydro+J/ model• Determination of J/ melting temperature • J/ suppression in Hot-wind• Calculation of J/ v2 • Future plan – forward rapidity • Summary

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Physics MotivationPhysics Motivation• Quark-Gluon-Plasma (QGP)

– New state of QCD matter expected to be created at high temperature (Tc = 160-190MeV).

• Quarkonia suppression in QGP– Color Debye Screening

• T.Matsui & H. Satz PLB178 416 (1986)

– Suppression depends on temperature (density) and radius of QQbar system.

• TJ/ : 1.6Tc~2.0Tc • T, T’ : ~ 1.1Tc

– Serve as the thermometer in QGP.

Color Screening

cc

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M.Asakawa and T.Hatsuda, PRL. 92, 012001 (2004)A. Jakovac et al. PRD 75, 014506 (2007)G.Aarts et al. arXiv:0705.2198 [hep-lat]. (Full QCD)

J/J/ Suppression at RHIC Suppression at RHIC• J/ suppression in A+A Collisions at RHIC

(dN/dy)AuAu

(dN/dy)pp x<Ncol> RAA =

CNM effects • Gluons shadowing • Nuclear absorption

Evaluated from J/ production in d+Au collisions. A.Adare et al. (PHENIX) arXiv:0711.3917

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Au+Au: A. Adare et al. (PHENIX) PRL 98 232301 (2007)Cu+Cu: A. Adare et al. (PHENIX) arXiv:0801.0220

Au+Au (|y|<0.35)

Au+Au (1.2<|y|<2.2)

Cu+Cu (|y|<0.35)

Cu+Cu (1.2<|y|<2.2)

•J/ suppression at mid-rapidity at RHIC is compatible to CNM effects except most central Au+Au collisions.•Stronger suppression at forward rapidity than CNM effects.

J/J/ Suppression at RHIC Suppression at RHIC• Two proposed scenarios:

– Gluon dissociation + recombination• Dissociation by thermal gluons supplemented by the regeneration

of J/ from ccbar coalescence – R. Rapp et al. [EPJC34, 91 (2005), arXiv:0712.2407], L. Yan et al. [PRL97,232301 (2006)], R. Thews [NPA783 301(2007)],A.Andronic et al.[nucl-th/0701079], etc– Need to take into account charm production and its modification in t

he medium, which are still unclear at RHIC.

– Sequential Melting of J/• Absence of the feed down J/ from c and ’ (30-40%) just above

Tc and melt of direct produced J/.– F. Karsch et al., PLB 637 (2006) 75 – Feed down fraction is unclear at RHIC (<~40% 90%CL).– This is still in a qualitative level and need to take into account the s

pace-time evolution to study dynamically.

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Hydro+J/Hydro+J/ model model

• First attempt for the study of sequential suppression of charmonia at RHIC.– Incorporate J/, c and ’ into the evolution of matter.

• Evolution of matter : (3+1)-dimentional relativistic hydrodynamics – T. Hirano and Y. Nara, PRL 91, 082301, (2003)– T. Hirano and Y. Nara, PRC 69, 034908, (2003)– T. Hirano and K. Tsuda, PRC 66, 054905, (2002)– http://tkynt2.phys.s.u-tokyo.ac.jp/~hirano/parevo/parevo.html

• J/, c and ’ : impurity traversing through the matter– Assume three kinds of interaction inside QGP.

» Free Streaming » Hot-Wind » Complete Thermalization

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T. Gunji et al. Phys. Rev. C 76:051901 (R), 2007

Modeling of J/Modeling of J/ suppression suppression

• Survival Prob. In the medium:

• Decay Width:

• Motion of J/: free streaming

• Total Survival Prob.

• Free Parameters:

– (TJ/, T, fFD )

0

))((exp)( /// dxTxS JdisJJ

J/x0

(pT)

7

0// )( xx JJ

,// )1( SfSfS FDJFDtotJ

• x0(Production point) is distributed according to the spatial Ncol distribution.• pT is distributed according tothe measured J/ distribution.• J/ azimuthal angle, , is flat (0 to 2).

)()1/(),()( /3

/ JcJdis TTTTTTT T. Song, Y. Park and S. H. Lee Phys.Lett.B659:621-627,2008.

Model resultsModel results

• Best Fit @ (TJ/, T, fFD) = (2.00Tc, 1.34Tc, 10%)

Bar: uncorrelated sys.Bracket: correlated sys.

• Onset of J/ suppression at Npart ~ 160.( Highest T at Npart~160 reaches to 2.0Tc.)• Gradual decrease of SJ/

tot above Npart~160 reflects transverse area with T>TJ/ increases.• TJ/can be determined in a narrow region.

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)(CNMRRS

AA

AAAA

Contour map

1

2

Decay width below TDecay width below TJ/J/

• Decay width :

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T. Song, Y. Park and S. H. Lee Phys.Lett.B659:621-627,2008.

)()1/(),()( /3

/ JcJdis TTTTTTT

• Suppression pattern is similar up to < 0.2. (T=2Tc)<~0.2 GeV

Hot-wind scenario Hot-wind scenario

• Melting temperature depends on the relative velocity between J/ and fluid.

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4/12 )1)(0()( vTvT meltmelt H. Liu, K. Rajagopal and U. A. Wiedemann : hep-ph/0607062.

(TJ/, T, FD) = (2.0Tc, 1.34Tc, 10%)

• Magnitude of the suppression in hotwind is similar to the free streaming case.• Gradual decrease above 50 is the effect of hot-wind. Next is SAA vs. pT! Free streaming Hot-

wind

pT dependence of SpT dependence of SAAAA 11

Free streaming Hot-wind

20-30%

0-10%

40-50% 50-60%

• pT dependence of the suppression is greatly different. • Suppression is flat in case of free streaming.• Suppression is stronger for high pT J/ in case of hot-wind as predicted.• Critical pT in hot-wind relates to the achieved temperature in fluid.

(TJ/, T, FD) = (2.0Tc, 1.34Tc, 10%)

Calculation of J/Calculation of J/ v2 v212

Free streaming Hot-wind(TJ/, T, FD) = (2.0Tc, 1.34Tc, 10%)

20-30%0-10%

40-50% 50-60%

v2 = 3%

v2 = 3%

• v2 is small (<1%) in case of free streaming.• v2 is larger for higher pT J/ in case of hot-wind (~3% v2).

• v2 increases above critical pT.

Thermalization ScenarioThermalization Scenario• Assume that J/ flows in the fluid (T>Tfo).

– J/ moves according to fluid velocity (T>Tfo) and freeze-out at Tfo. Momentum of J/ is distributed according to Boltzman eq. Then boost J/ according to fluid velocity.

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10-20%0-10%

20-30% 40-50%

v2 = 30%

Tfo = 1.0Tc

• v2 is much larger than that of free streaming and hot-wind case.•Large v2 is predicted in low-mid pT since most of J/in low-mid pT are followed by flow of the fluid. •Magnitude is similar to the case of coalescence model. But tendency is much different for high pT.

ThermalizationFree streaming Hot-wind

v2 = 30%

Future plan – forward Future plan – forward rapidity rapidity

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• Stronger suppression at forward rapidity : CGC? (M. Nardi’s talk Session VI)• Further studies will be done in conjunction with CGC.

SummarySummary• J/ suppression at RHIC was investigated using hydro+J/ mo

del.– Dynamical and quantitative approach to the sequential suppression.

• Comparison of the experimental survival probability shows:– Observed suppression is described well with TJ/~2.0Tc at mid-rapidity a

nd TJ/ can be determined in a narrow region. – Decay width seems to be (T=2Tc)<0.2 GeV.

• Hot-wind calculation was done in this model.– Large suppression and ~3% v2 in high pT region can be seen in a scenar

io with hot-wind. High pT J/psi is important for this model.– Critical pT depends on the achieved temperature in the fluid.

• Thermalization scenario shows :– larger v2 (10-30%) in low-mid pT region (pT<4 GeV) and small v2 (<5%) i

n high pT region. Much different from other scenarios. • Further studies of stronger suppression in forward rapidity will b

e done in conjunction with CGC. Effect of recombination will be studied.

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Back Up SlidesBack Up Slides

Feeze-out Temp. DependenceFeeze-out Temp. Dependence• Assume that “survived” J/ flows in the fluid.

– J/ moves according to fluid (T>Tfo) and freeze-out at Tfo. Momentum of J/ is distributed according to Boltzman eq.

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10-20%0-10%

20-30% 40-50%

v2 = 30% Tfo = 1.0TcTfo = 1.1TcTfo = 1.2Tc

• Most of low-mid pT J/y is from flowed J/y. • Large v2 is predicted due to the flow of fluid. • It depends on the freeze-out temp. of J/y.• Magnitude is similar in case of coalescence model. But tendency is Much different.

RAA

(1.2<|y|<2.2) /RAA

(|y|<0.35)

1

RAA

0

1

0

Bar: uncorrelated errorBracket : correlated error

Forward rapidityForward rapidity• Stronger suppressionat forward rapidity.

– Gluon saturation (CGC)?• Leading to suppression of charm production

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=2

Open charm yield in Au+Au @ 200 GeV

=0 ~60% Suppression patterndue to CGC

K. L. Tuchin hep-ph/0402298

(TJ/,T) = (2.02Tc,1.22Tc)FD = 30% (y=0), FD= (35-50)% (y=2)

Forward RapidityForward Rapidity• Experimental SJ/

tot (y=2)– CNM at y=0 & CGC suppression (y=2/y=0)

• Model SJ/tot (y=2)

– Hydro at y=2

• Need larger feed-down fraction at y=2.• Onset of suppression at Npart ~ 240?

• 2.02Tc is achieved at Npart~240 at y=2?

Further analysis is on going.

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SJ/(y=0)=RAA/CNM(y=0,abs=1mb)

SJ/(y=2)=RAA/R(CGC)/CNM(y=0,abs=1mb)

c feed-down fraction

Feed down fractionFeed down fraction• Feed down fraction

– ~40% of J/ from c and ’

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χ,1,2 J/ ~30%

΄ J/ 5.5%

Complete ThermalizationComplete Thermalization• T>Tc: J/ moves according to fluid velocity vecto

r.• T~Tc: J/ freeze-out:

– Re-arrange the J/ px, py and pz using Boltzman Eq (in local fluid coordinate).

– Then boost J/ according to the fluid velocity vector.

322

)exp( pdTc

pmN

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pT and v2 of flowed J/pT and v2 of flowed J/• J/ participating in the flow of the matter

dN/dpT [A.U] v2

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Melting temperatureMelting temperature• Spectral analysis in quenched lattice.

J/ c

J/ c

Datta, Karsch, Petreczky & Wetzorke, hep-lat/0312037

Asakawa & Hatsuda, hep-lat/0308034

Tc~270 MeV

J/ may survive up to ~2Tc. c and y’ would melt at ~1Tc.

T. Hatsuda QM2006 (hep-ph/0702293)

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Melting temperatureMelting temperature• Spectral analysis in full lattice (Nf=2).

T. Hatsuda QM2006 (hep-ph/0702293)

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Jc

Aarts et al., hep-lat/0610065

Even with the light quarks, J/ may survive up to ~2Tc.

Tc~170 MeV

pT [GeV]

Hydro. calculationHydro. calculation• (3+1) dimensional hydro. (,x,y,s)

– r, T, v(vx,vy) at (,x,y,s) 0 = 0.6 fm/c, Tc=170 MeV– Massless parton gas (u,d,s,g)– Tuned to reproduce dN/dh

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Hydro data are open to public:http://tkynt2.phys.s.u-tokyo.ac.jp/~hirano/parevo/parevo.html

T.Hirano and Y.Nara, PRL91,082301(2003);T.Hirano and Y. Nara PRC69,034908(2004);T.Hirano and K.Tsuda, PRC66,054905(2002).

Hydro+Jet modelHydro+Jet model• Hydro+“hard probe” works.

– Identified hadron spectrum

– Back-to-back correlation

– Pseudo-y dependence of RAA

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T. Hirano and Y. Nara PRL91 082301 (2003)

pT [GeV]

T. Hirano and Y. Nara PRC69 034908 (2004)

T. Hirano and Y. Nara PRC68 064902 (2003)

TTJ/J/ comparison comparison• This study shows TJ/~2.02Tc.

• Estimation of TJ/ in 3-falvor QCD from quenched lattice QCD.

3

/4/1

3

/

368/716

16f

f

Nc

qc

qc

J

Nc

J

T

T

T

T

T

T

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= 1.7 = 270/170Asakawa & Hatsuda, hep-lat/0308034

This coincides with the resultobtained in this study.

05.23

/

fNc

J

T

T

Map of SuppressionMap of Suppression• Example of suppression map

– 10-20% centrality, Tmelt = 1.0Tc Production probability map

Temperature Field (=0.6 fm/c)

Suppression Map(integrated over )

Similar to surface emission! Main component of survival J/psi

Small component (gained by large Ncoll )

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Sensitivity for TSensitivity for TJ/J/& FD& FD

• TJ//Tc = 1.88, 1.94,

2.00, 2.06, 2.12

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TJ/y can be determined in a narrow region around 2.00Tc.

Forward-RapidityForward-Rapidity• Use hydro at y=2

– (TJ/y, T, FD) free• (2.08Tc, 1.62Tc, 70%)• Chi2 = 0.83

– (TJ/y, T) fixed• (TJ/y, T) = (2.0, 1.34)

• FD45%, chi2 = 10

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Hot-wind in hydro+J/Hot-wind in hydro+J/ model modelT. Gunji, H. Hamagaki, T. Hatsuda, T. Hirano, Y. Akamatsu : Phys. Rev. C 76:051901 (R), 2007 Parallel talk at QM2008 by T. Gunji , Feb. 9th SessionXVIII 15:20~15:40

Melting temperatures : (TJ/, T) = (2.0Tc, 1.34Tc) 10% feed-down correction

4/12 )1)(0()( vTvT meltmelt

1: Survival Probability of J/ vs. Npart 20-30%Npart ~ 170

H. Liu et al. PRL.98:182301,2007

•J/ suppression from Hot-wind scenario was calculated in hydro+J/model.•Overall suppression pattern is similar in both cases. •Larger suppression and large v2 (~3%) in the high pT region in a scenario with hot-wind.

2: Survival Probability of J/ vs. pT

3: v2 of J/ vs. pT

Melting temperature in hot-wind