Cold and Hot nuclear matter effects on Charmonium production

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Cold and Hot nuclear matter effects on Charmonium production

Kai Zhou (Tsinghua University,Beijing)

In collaboration with:

Baoyi Chen (Tsinghua University)Yunpeng Liu (Frankfurt University)Nu Xu (CCNU)Pengfei Zhuang (Tsinghua University)

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Ø Motivation

Ø Cold & Hot Nuclear Matter Effects

Ø Numerical results at RHIC and LHC

Ø Summary

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Matsui and SatzMatsui and Satz: PLB178, 416(1986):: PLB178, 416(1986): J/Psi suppression as a probe of QGP in HICJ/Psi suppression as a probe of QGP in HIC

●● quarkonia can survive quarkonia can survive above Tcabove Tc,, a a sensitive signature of QGP formationsensitive signature of QGP formation

●● heavy quarks are produced via hard processes,heavy quarks are produced via hard processes, rather solid rather solid theoretical ground theoretical ground

Ø Motivation

color screening ----->

melting of the bound states ----->

yields suppressed

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Ø Motivation

extract information about QGP, but many effects should be taken into account:

Interplay of Hot and Cold Nuclear Matter effect:

--- Cold Effects : Shadowing, Nuclear Absorption, Cronin

--- Hot Effects : color screening, recombination

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Ø Cold & Hot Nuclear Matter Effects

Hydrodynamic Evolution formedium

Transport Equationfor Jpsi cold matter

effects

hot mattereffects

TransportTransport (Hot & Cold) (Hot & Cold) + + HydrodynamicHydrodynamic ApproachApproach

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

121

443

23

31

3

3

3

xkfxkfsWqqkpE

qd

E

qd

E

kd

m ccproccgt

)0(

)()0()( 2

2

Tr

TrTT gg

( , , )f p x t

●●the quarkoniumthe quarkonium distribution function in phase spacedistribution function in phase space

gluon dissociation cross section by gluon dissociation cross section by OPE (Peskin,1999)OPE (Peskin,1999)

regeneration by regeneration by detailed balancedetailed balance ! !

fromfrom Potential Model Potential Model

ccJg /

),,(,, tttttt pxfpxf

),(42)2(2

13

3

xkfFE

kd

m ggggt

)1/(1 / Tupge

Hot Effects

Ø Cold & Hot Nuclear Matter EffectsTransport Transport : Hot Nuclear Matter Effects: Hot Nuclear Matter Effects

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●●initial distributioninitial distribution for transport Eq. for transport Eq. including including Cold EffectsCold Effects 0( , , )f p x t

Cronin

Shadowing

AbsorptionCold

Effects

pT broadening (Gaussian smearing)

at LHC can safly be neglected y

NN

Tccg es

pmx

22

2,1

for Jpsi & charm

22 /15.0 cGeVagN @ LHC Pb-Pb 2.76TeV

Init.J.Mod.Phys.E.12,211(2003) Phys.Rev. C 73, 014904(2006)

02 )( inelasitic

ppgNa

R. Vogt, Phys. Rev. C 71 (2005) 054902

Ø Cold & Hot Nuclear Matter EffectsTransport Transport : Cold Nuclear Matter Effects: Cold Nuclear Matter Effects

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●● 2+1D 2+1D hydrodynamicshydrodynamics( )( )

●● EEquationquation O Off S Statetate: :

Ideal GasIdeal Gas with quarks and gluons for QGP & with quarks and gluons for QGP & HRGHRG

0 T

Longitudinal Bjorken Expansion

●● Initial conditions :Initial conditions :

Glauber model & constrained by Glauber model & constrained by Charged MultiplicitiesCharged Multiplicities or from or from well tewell tested HydroCodested HydroCode

0B

Ø Cold & Hot Nuclear Matter EffectsHydrodynamic Hydrodynamic : Background Medium Evolution: Background Medium Evolution

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Ø Numerical Results

RHIC Au-Au 0.2TeV : Ratio of 1.2<y<2.2 to |y|<0.35

rule out the approach with only cold matter effects.

shadowing effect is important,and the total yield is sensitiveto it.

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RHIC Au-Au 0.2TeV : Ratio of 1.2<y<2.2 to |y|<0.35

rule out the approach with only cold matter effects.

transverse momentum is notso sensitive to shadowing.

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LHC Pb-Pb 2.76TeV : Inclusive Jpsi

picked out from talk by E. Scomparin at QM2012( fot the ALICE Collaboration)

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LHC Pb-Pb 2.76TeV : 2.5<|y|<4.0 Inclusive Jpsi

the band due to considering ornot considering Shadowing

B-decay contribute~10% totaly

Reg. vs Init.@,most central co-llisions is larger than 50% : 50%

almost no centrality depende-nce above Np~100

mbdy

d

y

ccNN 38.0

45.2

FONLL

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LHC Pb-Pb 2.76TeV : 0 <|y|<0.9 Inclusive Jpsi

the band due to considering ornot considering Shadowing

B-decay contribute~10% totaly

Reg. vs Init.@,most central co-llisions is larger than 70% :30%

mbdy

d

y

ccNN 6.0

45.2

FONLL

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Ø Numerical Resultsprediction

Raa(Np) for different pt bins:

LHC Pb-Pb 2.76TeV :

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Ø Numerical Resultsprediction

Raa(Np) for different pt bins:

LHC Pb-Pb 2.76TeV :

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data : ALICE 0-90%


picked out from talk by E. Scomparin at QM2012

low pt region is dominatedby regeneration

Suppression increases withincreasing pt, a valley struc-ture

unvertainties arised from shadowing effect

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data : ALICE 0-90%

low pt region is dominatedby regeneration

Suppression increases withincreasing pt, a valley struc-ture

uncertainties arised from shadowing effect


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ppT

AAT

AAp

pr

2

2

1,compared to total yield, not so sensitive to the cold nuclear matter effects.

2, very sensitive to the degree of heavy quark thermalization.

NNs

hot mediumeffectstronger

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ppT

AAT

AAp

pr

2

2

1,compared to total yield, not so sensitive to the cold nuclear matter effects.

2, very sensitive to the degree of heavy quark thermalization.

NNs

hot mediumeffectstronger

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Ø Both the cold and hot nuclear matter effects are included self-consistently in the transport approach and the recent data support our prediction.

Ø While the total yield is sensitive to both the cold and hot effects,theTransverse Momentum Dependense is mainly controlled by the hot effect.

Ø

Ø Summary

ppT

AAT

AAp

pr

2

2

we introduce which can be used to probe the QGP formation at RHIC and LHC.

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Thank You!

2222

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

2323

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:

Cold and Hot nuclear matter effects on Charmonium production

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