Olena LinnykOlena Linnyk

Charmed hadron signals of partonic medium

BeijingBeijing

Our goal – properties of partonic matter

Hadron-string models

Experiment QGP models

Observables

Hadron abundances J/ anomalous suppression at SPS J/ anomalous suppression at RHIC J/ rapidity distribution at RHIC Elliptic flow of D-mesons Elliptic flow of J/ Quenching of charm at RHIC

HSD

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

• NoNo explicit quark and gluongluon degrees-of-freedom, partons only in the strings

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

Charmonium production in HSD

primary (Baryon+Baryon) secondary (meson+Baryon) recreation (D+D J/+meson)

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/d

t

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

NNDDDD~16~16

10 10010-1

100

101

102

103

104

105

106

10 100

10-1

100

101

102

103

104

105

106

107

D+Dbar +N

J/

/

all xF

N(s

) [n

b]

s1/2 [GeV]

J/

/

p+N

all xF

D+Dbar

pN(s

) [n

b]

Hard probebinary scaling!

Charmonium interactions with the medium in HSD

Default comover absorption scenario: Interactions with nucleons (normal nuclear absorption, as in pA) Absorption on formed mesons (comovers), J/+mD+D Recombination by D+Dbar annihilation, D+DJ/+m

Modified comover, i.e. prehadron interaction scenario: additionally, absorption and elastic scattering by prehadrons=mesons

and baryons under formation time of ~0.8 fm/c in their rest frame)

Observables

Hadron abundances J/ anomalous suppression at SPS J/ anomalous suppression at RHIC J/ rapidity distribution at RHIC Elliptic flow of D-mesons Elliptic flow of J/ Quenching of charm at RHIC

HSD

Hadron abundances• very good description of particle production in pp, pA reactions with HSD

• unique description of nuclear dynamics from low (~100 MeV) to ultrarelativistic (~20 TeV) energies

AGS NA49 BRAHMS

10-1 100 101 102 103 10410-6

10-4

10-2

100

102

104

AGS SPS RHIC HSD ' 99

__

D(c)

J/D(c)

KK+

+

Mul

tipl

icit

y

Au+Au (central)

Energy [A GeV]

J/ anomalous suppression at SPS

0 25 50 75 100 125 1500.000

0.005

0.010

0.015

B

(')

'

/ B

(J

/) J/

Pb+Pb, 158 A GeVHSD

NA50 1997 NA50 1998-2000 Comover absorption

ET [GeV]

Both J/ and ’ suppression in Pb+Pb and In+In @ 160 A GeV are consistent with the comover absorption scenario.

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

[OL et al., NPA 786 (2007) 183 ]

J/ anomalous suppression at RHICcomover scenariocomover scenario

-3 -2 -1 0 1 2 3

10-4

10-4

central, 0-20%B

dN

(J/

)/d

y

10-5

10-4

comover prehadron interactions PHENIX

Au+Au, s1/2=200 GeV

HSDsemi-central, 20-40%

semi-peripheral, 40-60%

B

dN

(J/

)/d

y

y-3 -2 -1 0 1 2 3

10-6

10-5

y

peripheral, 60-90%

0 100 200 300 4000.0

0.5

1.0

Npart

Au+Au, s1/2=200 GeVComover absorption

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

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

RA

A(J

/)

But: the suppression at mid-ymid-y is stronger than at forward yforward y, unlike data!

[OL et al., PRC 76 (2007) 041901; NPA 807 (2008) 79]

Centrality dependence reproduced

Prehadron interaction scenario

1. early interactions of charmonium (ccbar) and D-mesons with unformed (under formation time t = F , F ~0.8 fm/c) baryons and mesons = prehadrons

2. comover absorption with recombination by D-Dbar annihilation

Dissociation cross sections of charmonium by pre-hadrons: dis

cc pre-Baryon = 5.8 mb, dis

cc pre-meson = 2/3 discc pre-Baryon

Elastic cross sections with prehadrons: Charmonium - prehadrons: D-meson - prehadrons:

elcc pre-Baryon = 1.9 mb, el

D pre-Baryon = 3.9 mb,

elcc pre-meson = 2/3 el

cc pre-Baryon elD pre-meson = 2/3 el

cc pre-Baryon

Pre-hadronic interaction scenario only ‚simulates‘ the interactions in the QGP without(!) explicit partonic interactions and phase transition

=> NOT (yet!) a consistent description ! => PHSD

Fitted to PHENIX data

[For details see: OL et al., arXiv:0808.1504 Int J Mod Phys (2008)]

-3 -2 -1 0 1 2 3

10-4

10-4

central, 0-20%B

dN

(J/

)/d

y

10-5

10-4

comover prehadron interactions PHENIX

Au+Au, s1/2=200 GeV

HSDsemi-central, 20-40%

semi-peripheral, 40-60%

B

dN

(J/

)/d

y

y-3 -2 -1 0 1 2 3

10-6

10-5

y

peripheral, 60-90%

[OL et al., NPA 807 (2008) 79 ]

J/ anomalous suppression at RHIC

prehadronic interactionsprehadronic interactions

0 100 200 300 4000.0

0.5

1.0

Au+Au, s1/2=200 GeVPrehadron interactions

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

Npart

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

RA

A(J

/)

In the prehadronic interaction scenario, the J/rapidity distribution has the right shape, reproduces the PHENIX data! =>

describesdescribes RAA at mid- and forward-rapidity simultaneously.

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3In+In, E

beam=160 A GeV

0.068 +/- 0.04-0.016 +/- 0.039

0.10917 +/- 0.11574

-0.00711 +/- 0.05656

HSD central HSD peripheral NA60

v 2 (J/

)

Central / Peripheral

•Default hadron comover scenario underestimates the data;•Pre-hadron interactions lead to an increase of the elliptic flow v2 of D mesons;

•The pre-hadronic scenario is ~consistent with the preliminary PHENIX data=> strong initial flow of non-hadronic nature!

Elliptic flow of D-mesons

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5-0.05

0.00

0.05

0.10

0.15Au+Au, s1/2=200 GeV

HSD, D-mesons comover(+recombination) + prehadron interactions PHENIX PHENIX, QM'08

v 2 (p T

)

pT [GeV/c]

at SPS: v2 is hadronic;

[OL et al., NPA 807 (2008) 79 ]

at RHIC:

Elliptic flow of J/

[R.Granier de Cassagnac J Phys G 35 (2008) 104023,C.Silvestre J Phys G 35 (2008) 104136]

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

-0.10

-0.05

0.00

0.05

0.10

HSD

J/, Au+Au, s1/2=200 AGeV, |y|<1

min bias comover prehadron interactions

v 2 (p

T)

pT [GeV/c]

[OL et al., arXiv:0808.1504 Int J Mod Phys (2008)]

More data needed!

Quenching of D mesons at RHIC

[OL et al., arXiv:0808.1504 Int J Mod Phys (2008)]

Evidence of additional high pT suppression in

the most central collisions.

Suppression of D mesons in peripheral collisions is

consistent with a purely hadronic scenario.

0.0

0.5

1.0

1.5

2.0

0 1 2 3 4 5 60.0

0.5

1.0

1.5

0 1 2 3 4 5 6 7

PHENIX

RA

A(p

T)

RA

A(p

T)

HSD, comover

J/ from Au+Au, s1/2=200 GeV, mid-rapidityJ/

syst +/- 10%syst +/- 10%

20-40%0-20% centrality

syst +/- 13%

40-60% centrality

pT [GeV/c]

syst +/- 28%

60-92% centrality

pT [GeV/c]

0.0

0.5

1.0

1.5

2.0

0 1 2 3 4 5 60.0

0.5

1.0

1.5

0 1 2 3 4 5 6 7

PHENIX

RA

A(p

T)

RA

A(p

T)

HSD, comover HSD, comover

+prehadron interactions

J/ from Au+Au, s1/2=200 GeV, mid-rapidityJ/

syst +/- 10%syst +/- 10%

20-40%0-20% centrality

syst +/- 13%

40-60% centrality

pT [GeV/c]

syst +/- 28%

60-92% centrality

pT [GeV/c]

Quenching of J/ at RHIC

[OL et al., arXiv:0808.1504 Int J Mod Phys. E (2008)]

Strong suppression at low pT observed experimentally cannot be explained:

• by hadronic absorption of initially produced J/s

Possible indication of J/ formation by

parton coalescence!

• or by D+D recombination, since J/s would follow RAA pattern similar to D mesons.

Conclusions• In search for partonic phase signatures, an understanding of hadron

(string) matter effects is necessary, and HSD is the tool to model it

• Charm absorption at SPS is consistent with the hadronic comover picture

• But hadron comover absorption fails to describe the rapidity distribution of J/mesons from Au+Au at s1/2=200 GeV

• In the prehadronic interaction scenario, the data at s1/2=200 GeV for Au+Au at mid and forward rapidities are simultaneously reproduced

• However, RHIC data on high pT suppression and v2 of D mesons are not reproduced in the (pre-)hadron-string picture

=> evidence for a plasma pressure ?!

Review for Int. J. Modern Phys. E (September, 2008)arXiv:0808.1504

-2 -1 0 1 20.0

0.5

1.0

s1/2=200 GeV

Rd

A

y

PHENIX HSD

Supression in pA at RHIC

Charmonium is absorbed on baryons Effect of shadowing at forward y

[OL et al., NPA (2008) 807, 79]

• J/J/ suppression is qualitatively suppression is qualitatively ddescribed,escribed, butbut QGP threshold melting scenario shows a too QGP threshold melting scenario shows a too

strong strong ‚‚ absorption, which contradicts the absorption, which contradicts the NA50 data! NA50 data!

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

Dissociation energy densities:Dissociation energy densities:(J(J )=16 GeV/fm)=16 GeV/fm33, , ((c c ) =2 GeV/fm) =2 GeV/fm33, , (( ‚‚) =2 GeV/fm) =2 GeV/fm33

[OL et al., NPA 786 (2007) 183 ][OL et al., NPA 786 (2007) 183 ]

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

)) Gla

ub

er

Npart

J/ and ´ from threshold melting scenario at SPS

0.0

0.5

1.0

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

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

RA

A(J

/)

Au+Au, s1/2=200 GeV, QGP threshold scenario

+ recombinationD+Dbar J/ +m

without recombination

0 100 200 300

0.000

0.005

0.010

0.015

B

(')

'

/ B

(J

/) J

/

Npart

0 100 200 300 400

Npart

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

Threshold melting model: complete dissociation Threshold melting model: complete dissociation of initial of initial J/J/and and ´́ due to the huge local due to the huge local energy densities ! energy densities !

Charmonia recombination by D-Dbar annihilation Charmonia recombination by D-Dbar annihilation is important, however, it can not generate enough is important, however, it can not generate enough charmonia, especially for peripheral collisions! charmonia, especially for peripheral collisions!

[O Linnyk et al., [O Linnyk et al., PRC 76 (2007) 041901 PRC 76 (2007) 041901 ]]

J/ and ´ from threshold melting scenario at RHIC

Summary Threshold scenario vs Comover Threshold scenario vs Comover absorptionabsorptionSummary Threshold scenario vs Comover Threshold scenario vs Comover absorptionabsorption

I. QGP ‚threshold melting‘I. QGP ‚threshold melting‘

versus experimental data

SPS SPS RHICRHIC

J/J/survivalsurvival:: ++

‚‚/ J// J/ratio :ratio : ??

II. Comover absorption II. Comover absorption

(+ recombination by D-Dbar (+ recombination by D-Dbar annihilation)annihilation)

versus experimental data

SPS RHICSPS RHIC

J/J/survivalsurvival:: + +

‚‚/ J// J/ratio :ratio :

??ComoverComover absorption absorption and threshold melting and threshold melting scenarios are ruled out by scenarios are ruled out by experimentalexperimental data data

evidence for non-hadronic interaction ?!evidence for non-hadronic interaction ?!

Bjorken energy density

dy

dE

τA

1ε T

Bj

‚‚Local‘ energy densityLocal‘ energy densityduring transient timeduring transient time ttrr~0.13 fm/c~0.13 fm/c: : GeV/fmGeV/fm22/c] / [0.13 fm/c]/c] / [0.13 fm/c] ~ 30 GeV/fm~ 30 GeV/fm33 [OL et al., NPA (2008) 807, 79]

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

Local energy density from HSD

0

5

10

15

1

2

3

4

5

-10-5

05

10

Pb+Pb, 160 A GeVb=1 fm

[OL et al., NPA 786 (2007) 183 ]

At RHIC, energy-densities above the critical value (~2 GeV/fm3) exist in an extended space-time area

[OL et al., NPA (2008) 807, 79]

0 200 400 600 8000

1

2

3

4

5

6

7

HSD Comover QGP threshold Andronic et al

Pb+Pb, Ebeam

=158 A GeV, mid-rapidity

<J/

>/<

>

106

Ncoll

0 200 400 600 800 1000 12000

10

20

30

40

Andronic et al

Au+Au, s1/2=200 GeV, mid-rapidity

<J/

>/<

>

106

Ncoll

HSD Comover QGP threshold Prehadron interactions

Comparison to statistical hadronization

[OL et al., NPA (2008) 807, 79]