NN2012, San Antonio, May 27 - June 1, 2012NN2012, San Antonio, May 27 - June 1, 2012

Quarkonium Quarkonium Transverse Momentum Distribution Transverse Momentum Distribution as a Sensitive Signature of QGP as a Sensitive Signature of QGP

Pengfei Zhuang (Tsinghua University, Beijing)Pengfei Zhuang (Tsinghua University, Beijing)

● ● The J/The J/ΨΨ Puzzle Puzzle ●● A Detailed Transport Approach A Detailed Transport Approach ● ● Transverse Momentum DistributionTransverse Momentum Distribution

2

heavy quarks are mainly produced in the initial impact, almost no heavy quarks are mainly produced in the initial impact, almost no extra production in the later evolutionextra production in the later evolution

Quarkonium as a Probe of QGPQuarkonium as a Probe of QGP

Matsui and Satz, 1986:Matsui and Satz, 1986: J/J/ψψ as a probe of as a probe of QGP in heavy ion collisionsQGP in heavy ion collisions

What Is the Hot Medium Effect on Jpsi ?What Is the Hot Medium Effect on Jpsi ?

3

From Dissociation to Dissociation + RegenerationFrom Dissociation to Dissociation + Regeneration

there are about 10 pairs of c quarks in a central Au-Au collision at RHIC there are about 10 pairs of c quarks in a central Au-Au collision at RHIC energy and more than 100 pairs at LHC energy,energy and more than 100 pairs at LHC energy,

important quarkonium regeneration at high energies:important quarkonium regeneration at high energies: in QGPin QGP

in hadron gasin hadron gas

mesons

/c c J g Peter Braun-Munzinger group Peter Braun-Munzinger group Thews group Thews group Rapp group Rapp group

Problem: Problem: the competition between dissociation and the competition between dissociation and regeneration may reduce the difference between SPS, regeneration may reduce the difference between SPS, RHIC and LHC !RHIC and LHC !

62 GeV

J/J/ψψ Yield at SPS, RHIC and LHC Yield at SPS, RHIC and LHC

The Jpsi Yields at SPS, RHIC and The Jpsi Yields at SPS, RHIC and LHC Have Similar Behavior ! LHC Have Similar Behavior ! Is There a Jpsi Observable Which Is There a Jpsi Observable Which Is Sensitive to the Hot Medium?Is Sensitive to the Hot Medium?

The Jpsi Yields at SPS, RHIC and The Jpsi Yields at SPS, RHIC and LHC Have Similar Behavior ! LHC Have Similar Behavior ! Is There a Jpsi Observable Which Is There a Jpsi Observable Which Is Sensitive to the Hot Medium?Is Sensitive to the Hot Medium?

/

/

1,

<1, /

>1, /

JAA

AA Jc pp

no medium effect

R J supressionN

J enhancement

Transverse Momentum Distribution !Transverse Momentum Distribution !

Pt distribution is sensitive to the dynamics of the system Pt distribution is sensitive to the dynamics of the system and should tell us more about the nature of the medium. and should tell us more about the nature of the medium.

Data and Our Model PredictionData and Our Model Prediction

5

2

2

t AAAA

t pp

pR

p

+ equation of state + equation of state (ideal gas or lattice (ideal gas or lattice simulation)simulation)

A Full Transport Approach for Quarkonia in HICA Full Transport Approach for Quarkonia in HIC

●●quarkoniumquarkonium transport equations transport equations

●●initial production , including CNM. initial production , including CNM. 0( , , )f p x t

● ● QGPQGP hydrodynamics hydrodynamics

αα: suppression : suppression ββ: regeneration: regeneration

● ● analytic solution analytic solution

( / , ', )cJ

0, 0T n

Yunpeng Liu, Kai Zhou, ……, Nu Xu, PZ, 2005-2012Yunpeng Liu, Kai Zhou, ……, Nu Xu, PZ, 2005-2012

6

both initial production and regeneration suffer from screening !both initial production and regeneration suffer from screening !

Dissociation Cross Section Dissociation Cross Section

( ) / J g Q Q

( , )gp p●● gluon dissociation cross section calculated by OPE gluon dissociation cross section calculated by OPE (Bhanot, Peskin,1999):(Bhanot, Peskin,1999):

●● at finite temperature, we use the classical relationat finite temperature, we use the classical relation2

2

( )( , , ) ( , )

(0)g g

r Tp p T p p

r is calculated through the is calculated through the

Schroedinger equationSchroedinger equation

2 ( )r T

●● regeneration rate is determined by the detailed balanceregeneration rate is determined by the detailed balance

●● J/J/ΨΨ dissociation rate dissociation rate

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8

Charm Quark DistributionCharm Quark Distribution

Due to interaction with the medium, charm quarks become soft in the Due to interaction with the medium, charm quarks become soft in the medium, and therefore the regeneration happens mainly in the low pt region. medium, and therefore the regeneration happens mainly in the low pt region.

From observed D-meson flow at RHIC, charm quarks seem to be thermalized, From observed D-meson flow at RHIC, charm quarks seem to be thermalized, we take thermal distribution for charm quarks in the mediumwe take thermal distribution for charm quarks in the medium. .

Initial fraction and regeneration fraction for J/Initial fraction and regeneration fraction for J/ΨΨ produced in central Pb+Pb produced in central Pb+Pb collisions at LHC energy, with thermal charm quark distribution.collisions at LHC energy, with thermal charm quark distribution.

for a pQCD charm quark distribution, the initial production and for a pQCD charm quark distribution, the initial production and regeneration will behave similarly !regeneration will behave similarly !

STAR data, QM2011STAR data, QM2011

Transverse Momentum Distribution at RHIC (1) Transverse Momentum Distribution at RHIC (1)

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the competition between initial production and regeneration the competition between initial production and regeneration leads to a minimum.leads to a minimum.

we need more precise data. we need more precise data.

Y.Liu, Z.Qu, N.Xu, PZ, PLB2009Y.Liu, Z.Qu, N.Xu, PZ, PLB2009 Transverse Momentum Distribution at RHIC (2)Transverse Momentum Distribution at RHIC (2)

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Model Calculations: Model Calculations: 1)Peter Braun-Munzinger 1)Peter Braun-Munzinger group group 2)Ralf Rapp group 2)Ralf Rapp group 3)Tsinghua group3)Tsinghua group

ALICE Collaboration, arXiv:1202.1383ALICE Collaboration, arXiv:1202.1383

Centrality Distribution at LHC Centrality Distribution at LHC

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2

2

>1,

1,

1,

t AAAA

t pp

initial production at SPSp

R competition at RHICp

regeneration at LHC

Averaged Transverse Momentum (1)Averaged Transverse Momentum (1)

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Averaged Transverse Momentum (2)Averaged Transverse Momentum (2)

1) not sensitive to the shadowing effect1) not sensitive to the shadowing effect

2) for a pQCD charm quark distribution, the ratio behaves 2) for a pQCD charm quark distribution, the ratio behaves similarly at SPS, RHIC and LHCsimilarly at SPS, RHIC and LHC

Elliptic Flow at RHICElliptic Flow at RHIC

14almost no v2 at RHIC !almost no v2 at RHIC !

Elliptic flow at LHCElliptic flow at LHC

remarkable v2 at LHC !remarkable v2 at LHC !15

16

the quarkonium transverse momentum the quarkonium transverse momentum distribution is sensitive to the nature of distribution is sensitive to the nature of the medium and can be used to signal the the medium and can be used to signal the QGP formation in heavy ion collisions. QGP formation in heavy ion collisions.

ConclusionConclusion

BackupBackup

J/J/ΨΨ

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Input Input

● ● medium evolution medium evolution

0 pp 0

0 pp

0

: 0.6 , 41 , 344 MeV

: 0.6 , 62 ,

430 and 484 MeV for forward and mid rapidity

RHIC fm mb T

LHC fm mb

T

● ● initial production initial production 2

/

2

/

: 0, 0.1 GeV / ,

0.42 and 0.74 b for forward and mid rapidity

: 0, 0.15 GeV / ,

2.33 and 3.5 b for forward and mid rapidity

abs gN

Jpp

abs gN

Jpp

RHIC a fm

LHC a fm

● ● regeneration regeneration

d

: 0.04 and 0.12 for forward and mid rapidity

: 0.38 and 0.6 for forward and mid rapidity

V=U for T

ccpp

ccpp

RHIC mb

LHC mb

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Charmonium Charmonium in pp Collisionsin pp Collisions

observation: observation: '

/

( ' )/ , ' , 1.5%

( / )

pp X

pp J X

BJ

B J

mechanisms for quarkonium production in pp:mechanisms for quarkonium production in pp: it is difficult to describe quarkonium formation due to confinement it is difficult to describe quarkonium formation due to confinement problemproblem

color evaporationcolored /gg cc J

difficult to observe difficult to observe ψψ’ !’ !

ΨΨ’ and ’ and χχc c decay into J/decay into J/ψψ::

( / ) 30%

( ' / 2 ) 10%

direct production 60%

cP J

P J

ΨΨ’ ’

χχc c

J/J/ψψ

1) color evaporation model:1) color evaporation model:

/Jgg cc g

2) color-singlet model:2) color-singlet model:

: quantum numbers of color, angular momentum and spin

nn

gg cc X

n

3) color-octet model:3) color-octet model:

Y.Liu, N.Xu, PZ, JPG2010Y.Liu, N.Xu, PZ, JPG2010

Rapidity Dependence at RHICRapidity Dependence at RHIC

less regeneration in forward rapidity less regeneration in forward rapidity

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STAR data, QM2011STAR data, QM2011

high pt J/psi’s are from the initial production high pt J/psi’s are from the initial production and can survive in hot medium.and can survive in hot medium.

Transverse Momentum Dependence at RHIC Transverse Momentum Dependence at RHIC

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Centrality Distribution for High pt J/Centrality Distribution for High pt J/ψψs at LHCs at LHC

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24

25

26

27

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DD CorrelationDD Correlation

ATHIC III at Wuhan, October, 2010 30

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 at LHC, c quarks are fast thermalized, the strong flow push the D and Dbar to the near side!flow 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, (PHENEX, 2007; Moore and Teaney, 2005; Horowitz, Gyulassy, 2007).2007; Moore and Teaney, 2005; Horowitz, Gyulassy, 2007).

UpsilonUpsilon

ΥΥ, a Cleaner Probe at RHIC, a Cleaner Probe at RHIC

J/J/ψ ψ : : the production and suppression mechanisms the production and suppression mechanisms are complicated: there are primordial production and are complicated: there are primordial production and nuclear absorption in the initial state and regeneration nuclear absorption in the initial state and regeneration and anomalous suppression during the evolution of and anomalous suppression during the evolution of the hot medium.the hot medium. ΥΥ: : 1) the regeneration can be safely neglected; 1) the regeneration can be safely neglected; 2) there is almost no feed-down for2) there is almost no feed-down forΥΥ ; ;3) weaker shadowing effect 3) weaker shadowing effect

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ΥΥat RHIC: Rat RHIC: RAAAA( p( pt t ) )

Liu, Chen, Xu, Zhuang: arXiv:1009.2585,PLB2011Liu, Chen, Xu, Zhuang: arXiv:1009.2585,PLB2011

● ● strong Cronin effect strong Cronin effect

central Au+Au at √s=200 GeVcentral Au+Au at √s=200 GeV

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ΥΥat RHIC: at RHIC:

relation between relation between ϒϒ at RHIC and J/ at RHIC and J/ψψ at SPS: at SPS: ●● no no ϒϒ regeneration at RHIC and no J/ regeneration at RHIC and no J/ψψ regeneration at SPS regeneration at SPS

●● no no ϒϒ(1s) suppression at RHIC(1s) suppression at RHIC

no J/no J/ψψ suppression at SPS suppression at SPS

both are controlled by the Cronin effect !both are controlled by the Cronin effect !

2 ( )t pp N

(1 )

/

4

2

sD c RHIC

JD c SPS

T T T

T T T

2 2 2

2 2 2

/ /2.4

t t t gNAA pp

RHICRHIC SPS SPSgN Au

t t tSPS J JgN Pb

p p p a L

a Rp p p

a R

Liu, Chen, Xu, Zhuang: arXiv:1009.2585,PLB2011Liu, Chen, Xu, Zhuang: arXiv:1009.2585,PLB2011

Au+Au at √s=200 GeVAu+Au at √s=200 GeV

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ATHIC III at Wuhan, October, 201035

ΥΥat RHIC: Rat RHIC: RAAAA( N( Np p ) ) Y.Liu, B.Chen, N.Xu, PZ,PLB2011Y.Liu, B.Chen, N.Xu, PZ,PLB2011

●●from the comparison with data, V is close to U.from the comparison with data, V is close to U.

for minimum bias events:for minimum bias events: PHENIX dada: RPHENIX dada: RAAAA<0.64 (NPA2009) <0.64 (NPA2009)

our result: Rour result: RAA AA = 0.63 for V=U = 0.63 for V=U

RRAAAA= 0.53 for V=F= 0.53 for V=F

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ΥΥat LHC: Rat LHC: RAAAA( N( Np p ) )

●●again, V is close to U.again, V is close to U.

14 , 43 bbpp ppb nb

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ΥΥat LHC: Rat LHC: RAAAA( p( pt t ) )

high pt is controlled by initial production !high pt is controlled by initial production !

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Measuring RHIC Temperature by Excited Measuring RHIC Temperature by Excited ϒϒ States States

initial temperature dependence of Rinitial temperature dependence of RAAAA

central Au+Au at √s=200 GeVcentral Au+Au at √s=200 GeV

suppression of excited suppression of excited ϒϒ states is sensitive to the fireball temperature ! states is sensitive to the fireball temperature !

Liu, Chen, Xu, Zhuang: arXiv:1009.2585,PLB2011Liu, Chen, Xu, Zhuang: arXiv:1009.2585,PLB2011

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EoSEoS

Dependence on EoSDependence on EoS

J/Psi Pt distribution at LHC where EoS plays an essential role!J/Psi Pt distribution at LHC where EoS plays an essential role!

wQGPwQGP

sQGPsQGP

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Cold Nuclear EffectCold Nuclear Effect

Only Cold Nuclear Matter Effect ?Only Cold Nuclear Matter Effect ?

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