Olena LinnykOlena Linnyk

Charmonium in heavy ion collisionsCharmonium in heavy ion collisions

16 July 2007

Anomalous J/ suppression

0 100 200 300 4000

10

20

30

40

.

Pb+Pb, 158 A GeV

Npart

Baryon absorption Glauber model NA50 2004

Charm sector reflects the dynamics in the early phase of heavy-ion collisions !

J/ ‚normal‘ absorption by nucleons (Glauber model)

Experimental observation Experimental observation (NA38/50/60):(NA38/50/60):extra suppression in A+A collisions; increasing with centrality

Scenarios for anomalous charmonium suppression

• QGP colour screening

[Digal, Fortunato, Satz ’03]• Comover absorption

[Gavin & Vogt, Capella et al.`97] absorption by low energy inelastic scattering with ‚comoving‘ mesons (m=,,,...)

J/

C melting

0 20 40 60 80 100 120 1400

10

20

30

40

50

NA50 (2000):anal. Aanal. Banal. C

HSD UrQMD

B(

J/)

/(D

Y)| 2.

9-4.

5

Pb+Pb, 160 A GeV

ET [GeV]

J/+m D+Dbar

´ +m D+Dbar

C +m D+DbarDissociation energy density Dissociation energy density d d ~ 2(T~ 2(Tdd/T/Tcc))44

Quarkonium dissociation T:Quarkonium dissociation T:

Microscopical transport models provide the dynamical Microscopical transport models provide the dynamical description of description of nonequilibriumnonequilibrium effects in heavy-ion collisions effects in heavy-ion collisions

Transport modelsTransport models

Quark-Gluon-Plasma ?

time

DD

DDbarbar

J/J/

CC

‘‘

Check the scenarios using transport models

Initial StateHadronization

Freeze-out

HSD HSD – – HHadron-adron-SString-tring-DDynamics transport approachynamics transport approach

Charmonium production in pN

J/exp = J/ + B(cJ/) c + B(´->J/) ´

1 0 1 001 0-1

1 00

1 01

1 02

1 03

1 04

1 05

1 06

1 07

J /

/

p + N D + D b a r

(s)

[nb]

s1 /2 [G eV ]-4 -2 0 2 4

0

20

40

60

PHENIX HSD scaled with cross section ratio

pp->J/+X, s1/2=200 GeV

Br

d/d

y [n

b]

Hard probe binary scaling!

4.0 4.5 5.0 5.510

-1

100

101

J/+K*

J/+K

J/+

J/+

[m

b]

s1/2

[GeV]

• Phase-space model for charmonium + meson dissociation:

[PRC 67 (2003) 054903][PRC 67 (2003) 054903]

2. J/ recombination cross sections by D+Dbar annihilation: D+Dbar -> J/(c,‘) + meson (, K , K*) are determined by detailed balance!

4.0 4.5 5.0 5.5100

101

s1/2 [GeV]

D*+Dbar*

D+Dbar*, D*+Dbar

D+Dbar

[m

b]

20

2

Ψ

2χ

2J/Ψ

'C

6

432i

43214isospin4321

|M||M||M||M|

ΨJ/Ψ,χi

s

mm|M|

s

EEEE2gsσ

'C

,

constant matrix elementconstant matrix element

1. Charmonia dissociation cross sections with , K and K* mesons J/(c,‘) + meson (, K , K*) <-> D+Dbar

Modelling the comovercomover scenario in HSD

[Olena Linnyk et al., [Olena Linnyk et al., nucl-th/0612049, NPA 786 (2007) 183 ]nucl-th/0612049, NPA 786 (2007) 183 ]

Threshold energy densities:

J melting: (J )=16 GeV/fm3

c melting:(c ) =2 GeV/fm3

‚melting:( ‚) =2 GeV/fm3

0

5

10

15

1

2

3

4

5

-10-5

05

10

Pb+Pb, 160 A GeVb=1 fm

Energy density (x=0,y=0,z;t) from HSD

Modeling the QGP meltingQGP melting in HSD

Charmonium recombination by DDbar annihilation

5 10 15 20

10-8

10-7

10-6

10-5

10-4

10-3

time [fm/c]

J/+m->D+Dbar D+Dbar->J/+m

Pb+Pb, s1/2=17.3 GeV, central

dN

/dt

At SPS recreation of J/ by D-Dbar annihilation is negligible

5 10 15 20

10-4

10-3

10-2

10-1

time [fm/c]

J/+m->D+Dbar D+Dbar->J/+m

Au+Au, s1/2

=200 GeV, central

dN

/dt

But at RHIC recreation of J/ by D-Dbar annihilation is strong!

NNDDDD~16~16

Comparison to data

Pb+Pb and In+In @ 158 A GeV comover absorptioncomover absorption

[OL et al NPA786 (2007) 183]

Pb+Pb and In+In @ 160 A GeV consistent with the comover absorption

for the same parameter set!

0 25 50 75 100 125 150

0 50 100 150 2000

10

20

30

40

0 100 200 300 400

HSD

NA50 1997 NA50 1998-2000 Baryon absorption Comover absorption

ET [GeV]

0 50 100 150 2000.000

0.005

0.010

0.015

HSD

Baryon absorption Comover absorption

B

(')

' /

B

(J/

) J/

Npart

HSD

In+In, 158 A GeV

B(

J/)

/(D

Y)| 2.

9-4.

5

Npart

NA60 2005 Glauber model Baryon absoprtion Comover absorption .

HSD

Pb+Pb, 158 A GeV

Npart

NA50 2004 Glauber model Baryon absorption Comover absorption

0 50 100 150 200 250 300 350 4000.4

0.6

0.8

1.0

1.2

NA60, In+In, 158 A GeV (2007)HSD

NA60, In+In, 158 A GeV Comover absorption NA50, Pb+Pb, 158 A GeV Comover absorption

((J

/)/(

DY

)) /

((J

/)/(

DY

))G

laub

er

Npart

Pb+Pb and In+In @ 158 A GeV QGP threshold meltingthreshold melting

´ absorption too strong, which contradict data

[OL et al NPA786 (2007) 183]

0 25 50 75 100 125 150

0 50 100 150 2000

10

20

30

40

0 100 200 300 400

HSD

NA50 1997 NA50 1998-2000 QGP threshold melting

J/=16, c

=2, '=2 GeV/fm3

ET [GeV]

0 50 100 150 2000.000

0.005

0.010

0.015

HSD

QGP threshold melting

J/=16, c

=2, '=2 GeV/fm3

B

(')

' /

B

(J/

) J/

Npart

HSD

In+In, 158 A GeV

B(

J/

)/(

DY

)| 2.9-

4.5

Npart

NA60 2005 QGP threshold melting

J/=16, c

=2, '=2 GeV/fm3

HSD

Pb+Pb, 158 A GeV

Npart

NA50 2004 QGP threshold melting

J/=16, c

=2, '=2 GeV/fm3

0 50 100 150 200 250 300 350 4000.4

0.6

0.8

1.0

1.2

NA60, In+In, 158 A GeV (2007)HSD

NA60, In+In, 158 A GeV QGP threshold melting NA50, Pb+Pb, 158 A GeV QGP threshold melting

((J

/)/(

DY

)) /

((J

/)/(

DY

))G

laub

er

Npart

(J )=16 GeV/fm3, (c ) =( ‚) =2 GeV/fm3

Au+Au @ s1/2=200 GeV Comover absorptionComover absorption

[OL et al arXiv:0705.4443]

0.0

0.5

1.0

HSD |y|<0.35 1.2<|y|<2.2

RA

A(J

/)

PHENIX, |y|<0.35 PHENIX, 1.2<|y|<2.2

Au+Au, s=200 GeV, comover absorption

0 100 200 300

0.000

0.005

0.010

0.015

D+Dbar J/ +m

B

(')

'

/ B

(J

/) J/

Npart

0 100 200 300

D+Dbar J/ +m

+ cut

=1 GeV/fm3

Npart

Space for partonic effects

In the comover scenario the J/suppression at mid-

rapidity is stronger than at forward rapidity, unlike the data!

Energy density cut cut=1 GeV/fm3 reduces the meson comover absorption

||

0.0

0.5

1.0

HSD |y|<0.35 1.2<|y|<2.2

RA

A(J

/)

PHENIX, |y|<0.35 PHENIX, 1.2<|y|<2.2

+ recombinationD+Dbar J/ +m

without recombination

0.0

0.5

1.0

+ recombinationD+Dbar J/ +m

+ cut

=1 GeV/fm3

Au+Au, s=200 GeV, QGP threshold scenario

0 100 200 300

0.000

0.005

0.010

0.015

B

(')

'

/ B

(J

/) J/

Npart

0 100 200 300

Npart

0 100 200 300 400

0.000

0.005

0.010

0.015

Npart

Au+Au @ s1/2=200 GeV Threshold meltingThreshold melting

Satz’s model: complete dissociation of Satz’s model: complete dissociation of initial J/initial J/and and ´ due to the very large ´ due to the very large local energy densities ! local energy densities !

Charmonia recombination Charmonia recombination is important!is important!

Energy density cut Energy density cut cutcut=1 GeV/fm=1 GeV/fm33 reduces the reduces the meson comover absorption, however, D+Dbar meson comover absorption, however, D+Dbar

annihilation can not generate enough charmonia,annihilation can not generate enough charmonia,especially for peripheral collisions! especially for peripheral collisions!

QGP threshold melting scenario is ruled out by PHENIX data!QGP threshold melting scenario is ruled out by PHENIX data!

J/J/ excitation function

Comover reactions in the hadronic phase give almost a constant suppression;

pre-hadronic reactions lead to a larger recreation of charmonia with Ebeam .The J/ melting scenario with hadronic comover recreation shows a maximum

suppression at Ebeam = 1 A TeV; exp. data ? exp. data ?

100 1000 100000.0

0.2

0.4

0.6

0.8

1.0

Central

S

Ebeam

, A GeV

Comover + cut

Comover

QGP + cut

QGP

100 1000 100000.0

0.2

0.4

0.6

0.8

1.0

Minimum bias

HSD

SE

beam, A GeV

´́ excitation function

´ suppression provides independent information on absorption vs. recreation mechanisms !

100 1000 100000.000

0.004

0.008

0.012

Central

B

( ')

'

/ B

(J

/) J/

Ebeam

, A GeV

Comover+cut

Comover

QGP+cut

QGP

100 1000 10000

Minimum bias

HSD

' to J/ ratio

Ebeam

, A GeV

J/ probes early stages of fireball and HSD is the tool to model it.

Comover absorption and threshold melting both reproduce J/ survival in Pb+Pb as well as in In+In @ 158 A GeV, while ´ data are in conflict with the melting scenario.

Comover absorption and colour screening fail to describe Au+Au at s1/2=200 GeV at mid- and forward rapidities simultaneously.

Deconfined phase is clearly reached at RHIC, but a theory having the relevant/proper degrees of freedom in this regime is needed to study its properties (PHSD).

PHSD - PHSD - transport description of the partonic and hadronic phasestransport description of the partonic and hadronic phases

arXiv:0705.4443 arXiv:0704.1410 nucl-th/0612049

Back-up slide 1local energy density vsvs Bjorken

energy density • transient time for central Au+Au at 200 GeV:transient time for central Au+Au at 200 GeV: t tr r ~ 2R~ 2RAA//cmcm ~ 0.13 fm/c ~ 0.13 fm/c

• cc formation time: cc formation time: C C ~ 1/M~ 1/MT T ~ ~ 1/4GeV ~ 0.05 fm/c < t1/4GeV ~ 0.05 fm/c < trr

• cc pairs are produced in the initial NN collisions in time period tcc pairs are produced in the initial NN collisions in time period tr r

0 100 200 300 4000

1

2

3

4

5

0 100 200 300 4000

1

2

3

4

5

6

7

PHENIX HSD

Au+Au, 200 GeV

dE

T/d

/0.

5Npa

rt [

GeV

]

Npart

PHENIX HSD

Au+Au, 200 GeV

B

j* [

GeV

/fm

2 /c]

Npart

dy

dE

τA

1ε T

Bj

Bjorken energy density:Bjorken energy density:

JJ

cc

‚‚

at RHICat RHIC BjBj ~ 5 GeV/fm~ 5 GeV/fm22/c/c

AAis the nuclei transverse overlap areais the nuclei transverse overlap area is the formation time of the mediumis the formation time of the medium

‚‚Local‘ energy densityLocal‘ energy densityduring during

transient time ttransient time trr GeV/fmGeV/fm22/c] / [0.13 fm/c]/c] / [0.13 fm/c] ~ 30 GeV/fm~ 30 GeV/fm33

accounting accounting CC : :~ 28 GeV/fm~ 28 GeV/fm33

HSD reproduces PHENIX data for Bjorken energy density very wellHSD reproduces PHENIX data for Bjorken energy density very well HSD results are consistent with simple estimates for the energy density HSD results are consistent with simple estimates for the energy density

Back-up slide 2 PHSDInitial A+A collisions – HSD: Initial A+A collisions – HSD: string formation and decay to pre-hadronsstring formation and decay to pre-hadrons

Fragmentation of pre-hadrons into quarks:Fragmentation of pre-hadrons into quarks: using the quark spectral functions from the Dynamical QuasiParticle ModelDynamical QuasiParticle Model ( (DQPM) approximation to QCD

Partonic phase: quarks and gluons (= Partonic phase: quarks and gluons (= ‚dynamical quasiparticles‘)‚dynamical quasiparticles‘) with with off-shell spectral functionsoff-shell spectral functions (width, mass) defined by DQPM (width, mass) defined by DQPM

elastic and inelastic parton-parton interactions:elastic and inelastic parton-parton interactions: using the effective cross sections from the DQPM q + qbar (flavor neutral) <=> gluon (colored) gluon + gluon <=> gluon (possible due to large spectral width) q + qbar (color neutral) <=> hadron resonances

Hadronization: Hadronization: based on DQPM - based on DQPM - massive, off-shell quarks and gluons massive, off-shell quarks and gluons with broad spectral functions hadronize to with broad spectral functions hadronize to off-shell mesons and baryons:off-shell mesons and baryons: gluons gluons q + qbar; q + qbar q + qbar; q + qbar meson; q + q +q meson; q + q +q baryon baryon

Hadronic phase: hadron-string interactions – Hadronic phase: hadron-string interactions – off-shell HSDoff-shell HSD

DQPM: Peshier, Cassing, PRL 94 (2005) 172301;DQPM: Peshier, Cassing, PRL 94 (2005) 172301; Cassing, arXiv:0704.1410[nucl-th], NPA‘07 Cassing, arXiv:0704.1410[nucl-th], NPA‘07

Basic concepts of Hadron-String Dynamics

• for each particle species i (i = N, R, Y, , , K, …) the phase-space density fi

follows the transport equations

with the collision terms Icoll describing: elastic and inelastic hadronic reactions formation and decay of baryonic and mesonic resonances string formation and decay (for inclusive production: BB(for inclusive production: BBXX, mB, mBXX, , XX =many particles) =many particles)

• Implementation of detailed balance on the level of 12 and 22 reactions (+ 2n multi-meson fusion reactions)

• Off-shell dynamics for short living states

BB BB B´B´, BB B´B´, BB B´B´m, mB B´B´m, mB m´B´, mB m´B´, mB BB´́

),...,f,f(fI,t)p,r(fHHt M21colliprrp