Parton-Hadron-String-Dynamics at NICA energies Elena Bratkovskaya Institut für Theoretische Physik, Uni. Frankfurt Round Table Discussion IV: Round Table

Parton-Hadron-String-Dynamics Parton-Hadron-String-Dynamics at NICA energiesat NICA energies

EElenalena Bratkovskaya Bratkovskaya

Institut für Theoretische PhysikInstitut für Theoretische Physik, Uni. Frankfurt, Uni. Frankfurt

Round Table Discussion IVRound Table Discussion IV::‚‚Searching for the mixed phase of strongly interacting matter atSearching for the mixed phase of strongly interacting matter at

the Nuclotron-based Ion Collider fAcility (NICA)the Nuclotron-based Ion Collider fAcility (NICA)‘‘9-12 September 2009 9-12 September 2009 , , JINR, Dubna JINR, Dubna

Our ultimate goals:Our ultimate goals:

• Study of the Study of the phase phase transitiontransition from from

hadronic to partonic hadronic to partonic matter – matter –

Quark-Gluon-PlasmaQuark-Gluon-Plasma

• Search for the Search for the critical pointcritical point

• Study of the Study of the in-mediumin-medium properties of hadrons properties of hadrons at high baryon density and temperature at high baryon density and temperature

The phase diagram of QCDThe phase diagram of QCD

NICANICA

The QGP in Lattice QCDThe QGP in Lattice QCD

0.5 1.0 1.5 2.0 2.5 3.00

2

4

6

8

10

12

14

Z. Fodor et al., PLB 568 (2003) 73

Lattice QCD: B=0 B=530 MeV

T/Tc

/T4

TTcc = 170 MeV= 170 MeV

Lattice QCD:Lattice QCD: energy density versus temperatureenergy density versus temperature

QQuantum uantum CCromo romo DDynamics :ynamics :

predicts strong increase ofpredicts strong increase ofthe the energy density energy density at critical at critical temperature temperature TTC C ~170 MeV~170 MeV

PossiblePossible phase transition phase transition fromfrom hadronic to hadronic to partonic matter partonic matter (quarks, gluons) at critical energy (quarks, gluons) at critical energy densitydensity CC~1 GeV/fm~1 GeV/fm3 3

Critical conditions - Critical conditions - CC~1 GeV/fm~1 GeV/fm33 , T , TC C ~170 MeV ~170 MeV -- can be reached can be reached

in in heavy-ion experimentsheavy-ion experiments at bombarding energies at bombarding energies > 5 GeV/A > 5 GeV/A

‚Little Bangs‘ in the Laboratory

time

Initial State Hadronization

Au Au

Quark-Gluon-Plasma ?

quarks and gluons hadron degrees

of freedom

hadron degrees

of freedom

How can we proove that an equilibrium QGP has been How can we proove that an equilibrium QGP has been created in central Au+Au collisions ?! created in central Au+Au collisions ?!

• Strangeness enhancement Strangeness enhancement • Multi-strange particle enhancement in A+A Multi-strange particle enhancement in A+A • Charm suppressionCharm suppression• Collective flow (vCollective flow (v11, v, v22))• Thermal dileptonsThermal dileptons• Jet quenching and angular correlationsJet quenching and angular correlations• High pHigh pTT suppression of hadrons suppression of hadrons• Nonstatistical event by event fluctuations and correlations Nonstatistical event by event fluctuations and correlations • ... ...

Experiment: Experiment: measures measures final hadrons and leptonsfinal hadrons and leptons

Signals of the phase transition:Signals of the phase transition:

How to learn about How to learn about physics from data?physics from data?

Compare with theory!Compare with theory!

• Statistical models:Statistical models:basic assumptionbasic assumption: system is described by a (grand) canonical ensemble of : system is described by a (grand) canonical ensemble of non-interacting fermions and bosons in non-interacting fermions and bosons in thermal and chemical equilibriumthermal and chemical equilibrium

[ [ -:-: no dynamics] no dynamics]

• Ideal hydrodynamical models:Ideal hydrodynamical models:basic assumptionbasic assumption: conservation laws + equation of state; assumption of : conservation laws + equation of state; assumption of local thermal and chemical equilibriumlocal thermal and chemical equilibrium

[ [ -:-: - simplified dynamics] - simplified dynamics]

• Transport models:Transport models:based on transport theory of relativistic quantum many-body systems -based on transport theory of relativistic quantum many-body systems -off-shell Kadanoff-Baym equations for the Green-functions Soff-shell Kadanoff-Baym equations for the Green-functions S<<

hh(x,p) in (x,p) in

phase-space representation. phase-space representation. Actual solutions:Actual solutions: Monte Carlo simulations with Monte Carlo simulations with a large number of test-particlesa large number of test-particles

[[+: +: full dynamics | full dynamics | -:-: very complicated] very complicated]

Basic models for heavy-ion collisions Basic models for heavy-ion collisions

Microscopic transport models provide a unique Microscopic transport models provide a unique dynamicaldynamical description description of of nonequilibriumnonequilibrium effects in heavy-ion collisions effects in heavy-ion collisions

10-1 100 101 102 103 104

10-6

10-4

10-2

100

102

104

AGS SPS RHIC HSD ' 99

__

D(c)

J/D(c)

KK+

+

Mul

tiplic

ity

Au+Au (central)

Energy [A GeV]

HSD microscopic transport model - basic conceptHSD microscopic transport model - basic concept

HSDHSD – – HHadron-adron-SString-tring-DDynamics transport approachynamics transport approachBasic concept:Basic concept:Generalized transport equationsGeneralized transport equations on the basis of the on the basis of the off-shelloff-shell Kadanoff-Baym Kadanoff-Baym equations for Greens functions Gequations for Greens functions G<<

hh(x,p) in phase-space representation(x,p) in phase-space representation (accounting for the first order gradient expansion of the Wigner transformed (accounting for the first order gradient expansion of the Wigner transformed Kadanoff-Baym equations Kadanoff-Baym equations beyond the quasiparticle approximationbeyond the quasiparticle approximation).).Actual solutions:Actual solutions: Monte Carlo simulations with a large number of test-particlesMonte Carlo simulations with a large number of test-particlesDegrees of freedom in HSD:Degrees of freedom in HSD: hadrons hadrons - baryons and mesons including excited states (resonances)- baryons and mesons including excited states (resonances) strings strings – excited color singlet states – excited color singlet states (qq-q)(qq-q) or or (q-qbar)(q-qbar) leading quarksleading quarks (q, qbar)(q, qbar) & & diquarks diquarks (q-q, qbar-qbar) (q-q, qbar-qbar)

HSD – a microscopic model for heavy-ion HSD – a microscopic model for heavy-ion reactions: reactions:

• very good description of particle production invery good description of particle production in pp, pA reactionspp, pA reactions

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

Hadron-string Hadron-string transport models versus transport models versus observables observables

100

101

102

103

104

101

102

103

100

101

102

103

104

101

102

103

Elab

/A [GeV]

E895NA49BRAHMS

HSD UrQMD

+

4 yield

E895NA49BRAHMS

100

101

102

103

104

100

101

102

100

101

102

103

104

10-2

10-1

100

101

102

100

101

102

103

104

0

20

40

60

80

100

4 yield

E866NA49BRAHMS

K+

E866NA49BRAHMS

K

E877NA49

Elab

/A [GeV]

+0

Reasonable description of Reasonable description of strangenessstrangeness by by HSD and UrQMD (deviations < 20%) HSD and UrQMD (deviations < 20%)

works very well,works very well,

but where do we fail ?but where do we fail ?

NICANICA

NICANICA

NICANICA

NICANICA

NICANICA

Hadron-string Hadron-string transport models versus transport models versus observables observables

100 101 102 103 1040.00

0.05

0.10

0.15

0.20

0.25

E866 NA49 BRAHMS, 5%

HSD UrQMD

<K+>/<+>

Elab

/A [GeV]

1 10 1000.10

0.15

0.20

0.25

0.30

0.35

s1/2

[GeV]

E866 NA49 NA44 STAR BRAHMS PHENIX

Au+Au / Pb+Pb -> K++X

T [

GeV

]

HSD HSD with Cronin eff. UrQMD

‚‚horn‘horn‘in Kin K++//++

‚‚step‘step‘in slope Tin slope T

Exp. data are not reproduced in terms of the hadron-string picture Exp. data are not reproduced in terms of the hadron-string picture => evidence for=> evidence for nonhadronic degrees of freedom nonhadronic degrees of freedom

• Strangeness signals of QGPStrangeness signals of QGP

Transport description of theTransport description of the partonic partonic andand hadronic phase hadronic phase

Parton-Hadron-String-Dynamics

(PHSD)

From hadrons to partonsFrom hadrons to partons

In order to study of the In order to study of the phase transitionphase transition from from hadronic to partonic matter – hadronic to partonic matter – Quark-Gluon-PlasmaQuark-Gluon-Plasma – – we we need need a a consistent transport model withconsistent transport model withexplicit explicit parton-parton interactionsparton-parton interactions (i.e. between quarks and gluons) (i.e. between quarks and gluons) outside strings!outside strings!explicit explicit phase transitionphase transition from hadronic to partonic degrees of freedom from hadronic to partonic degrees of freedomlQCD EoS lQCD EoS for partonic phase => for partonic phase => phase transition is always a cross-overphase transition is always a cross-over

PParton-arton-HHadron-adron-SString-tring-DDynamics (ynamics (PHSDPHSD))

QGP phase QGP phase described by input from thedescribed by input from the

DDynamical ynamical QQuasiuasiPParticle article MModel odel (DQPMDQPM)

Transport theoryTransport theory: off-shell Kadanoff-Baym equations for the : off-shell Kadanoff-Baym equations for the Green-functions SGreen-functions S<<

hh(x,p) in phase-space representation with the(x,p) in phase-space representation with the

partonic partonic andand hadronic phase hadronic phase

A. A. Peshier, W. Cassing, PRL 94 (2005) 172301;Peshier, W. Cassing, PRL 94 (2005) 172301; Cassing, NPA 791 (2007) 365: NPA 793 (2007) Cassing, NPA 791 (2007) 365: NPA 793 (2007)

W. Cassing, E. Bratkovskaya, PRC 78 (2008) 034919;W. Cassing, E. Bratkovskaya, PRC 78 (2008) 034919;arXiv:0907.5331 [nucl-th], NPA‘09; arXiv:0907.5331 [nucl-th], NPA‘09;

W. Cassing, W. Cassing, EEPJ ST PJ ST 168168 (2009) (2009) 33

The Dynamical QuasiParticle Model (DQPM)The Dynamical QuasiParticle Model (DQPM)

Interacting quasiparticles :Interacting quasiparticles : massive quarks and gluonsmassive quarks and gluons

with spectral functions with spectral functions

T = 1.053 TT = 1.053 Tcc T = 1.35 TT = 1.35 TccT = 3 TT = 3 Tcc

•DQPMDQPM well matches well matches lQCDlQCD

•DQPMDQPM provides provides mean-fields for gluons and quarksmean-fields for gluons and quarks as well as as well as effective effective 2-body interactions 2-body interactionsand gives and gives transition ratestransition rates for the formation of hadrons for the formation of hadrons PHSDPHSD

Gluon‘s Gluon‘s

Peshier, Cassing, PRL 94 (2005) 172301;Peshier, Cassing, PRL 94 (2005) 172301; Cassing, NPA 791 (2007) 365: NPA 793 (2007) Cassing, NPA 791 (2007) 365: NPA 793 (2007)

PHSD - basic conceptsPHSD - basic concepts

Initial 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: Partonic phase: quarks and gluons (= 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 with broad spectralbroad spectral functions hadronize tofunctions hadronize to off-shell mesons and baryons:off-shell mesons and baryons:gluons gluons q + qbar; q + qbar; q + qbar q + qbar meson (or string); meson (or string); q + q +q q + q +q baryon baryon (or string)(or string) (strings act as ‚doorway states‘ for hadrons) (strings act as ‚doorway states‘ for hadrons)

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

DQPM: Peshier, Cassing, PRL 94 (2005) 172301;DQPM: Peshier, Cassing, PRL 94 (2005) 172301; Cassing, NPA 791 (2007) 365: NPA 793 (2007) Cassing, NPA 791 (2007) 365: NPA 793 (2007)

0 2 4 6 8 10 12

0

500

1000

1500

T = 1.7 TC

= 0

gluonsB +B

q +qmesons

part

icle

num

ber

time [fm/c]

PHSD: hadronizationPHSD: hadronization

Consequences:Consequences: Hadronization:Hadronization: q+qbar or 3q or 3qbar fuse to q+qbar or 3q or 3qbar fuse to a a color neutral hadrons (or strings)color neutral hadrons (or strings) which furtheron decay to hadrons which furtheron decay to hadrons in ain a microcanonical fashion, i.e.microcanonical fashion, i.e. obeying all conservation laws obeying all conservation laws (i.e. 4-(i.e. 4-momentum conservation, flavor current conservation)momentum conservation, flavor current conservation) in each eventin each event Hadronization Hadronization yieldsyields an increase in total entropy San increase in total entropy S (i.e. more (i.e. more hadrons in the final state than initial partons )hadrons in the final state than initial partons ) and not a decrease as in and not a decrease as in the simple recombination model !the simple recombination model !

Off-shell parton transportOff-shell parton transport roughly leads a roughly leads a hydrodynamic evolutionhydrodynamic evolutionof the partonic systemof the partonic system

E.g.E.g. time evolution of thetime evolution of thepartonic fireballpartonic fireball at temperature at temperature 1.7 T1.7 Tcc with with initialized initialized at at qq=0=0

W. Cassing, E. Bratkovskaya, PRC 78 (2008) 034919;W. Cassing, E. Bratkovskaya, PRC 78 (2008) 034919;arXiv:0907.5331 [nucl-th], NPA‘09; arXiv:0907.5331 [nucl-th], NPA‘09;

W. Cassing, W. Cassing, EEPJ ST PJ ST 168168 (2009) (2009) 33

PHSD: Expanding fireball PHSD: Expanding fireball

2 4 6 8 10

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10 time: 1 fm/c

z

x

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10 time: 3 fm/c

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x

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20.00

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10 time: 5 fm/c

z

x

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4.000

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5.600

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7.200

8.000

2 4 6 8 10

2

4

6

8

10 time: 1 fm/c

z

x

0

12.00

24.00

36.00

48.00

60.00

72.00

84.00

96.00

108.0

120.0

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8

10 time: 3 fm/c

z

x0

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100.0

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10 time: 5 fm/c

zx

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200.0

225.0

250.0

Time-evolution of parton densityTime-evolution of parton density

Time-evolution of hadron densityTime-evolution of hadron density

Expanding grid: Expanding grid: Δz(t) = ΔzΔz(t) = Δz00(1+a t) !(1+a t) !

PHSD: PHSD: spacial phase ‚co-existence‘spacial phase ‚co-existence‘ of partons and hadrons, but NO of partons and hadrons, but NO interactions between hadrons and partons (since it is a cross-over)interactions between hadrons and partons (since it is a cross-over)

Application to nucleus-nucleus collisionsApplication to nucleus-nucleus collisions

energy balanceenergy balance particle balanceparticle balance

0 3 5 8 10 13 15 18 200

1000

2000

3000

4000

Etot

Ep

Em E

B

# [G

eV]

Pb+Pb, 158 A GeV, b=1 fm

t [fm/c]

central Pb + Pb at 158 A GeVcentral Pb + Pb at 158 A GeV

only about 40% of the converted energy goes to partons;only about 40% of the converted energy goes to partons;the rest is contained in the ‚large‘ hadronic corona!the rest is contained in the ‚large‘ hadronic corona!

0 3 5 8 10 13 15 18 200

500

1000

1500

2000

partons mesons new B+Bbar

Num

ber

Pb+Pb, 158 A GeV, b=1 fm

t [fm/c]

Cassing & Bratkovskaya, arXiv:0907.5331 [nucl-th], NPA (2009)Cassing & Bratkovskaya, arXiv:0907.5331 [nucl-th], NPA (2009)

Partonic phase at NICA energiesPartonic phase at NICA energies

2 3 4 5 6 7 8 9 100.0

0.1

0.2

0.3

0.4 b [fm] 1 3 5 7 9 11 13

part

onic

ene

rgy

frac

tion

Pb+Pb, 158 A GeV

t [fm/c]

partonic energy fraction vs centrality and energypartonic energy fraction vs centrality and energy

Dramatic decrease of partonic phase Dramatic decrease of partonic phase with decreasing energy with decreasing energy and centrality and centrality

0 3 5 8 10 13 15 18 200.0

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part

onic

ene

rgy

frac

tion

Tkin

[A GeV] 10 20 40 80 160

Pb+Pb, b=1 fm

t [fm/c]


Proton stopping at SPS / NICAProton stopping at SPS / NICA

looks not bad in comparison to NA49 data,looks not bad in comparison to NA49 data, but not sensitive to parton dynamics but not sensitive to parton dynamics (PHSD = HSD)!(PHSD = HSD)!

-3 -2 -1 0 1 2 30

10

20

30

40

50 Pb+Pb, 7% central

NA49 PHSD40 A GeV 80 A GeV

p

dN/d

y

y-3 -2 -1 0 1 2 3

0

10

20

30

40

50bin NA49 PHSD 0 1 2 3 4 5

_

p-p

Pb+Pb 158 A GeV

dN/d

y

y


0

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10

15

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25

30

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5

10

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20

-4 -3 -2 -1 0 1 2 3 -4 -3 -2 -1 0 1 2 3 4

Pb+Pb

40 A GeV, 7% central


dN/d

y

yyy


K+

K+

K+

HSD PHSD

K

K

K

Rapidity distributions of Rapidity distributions of , K, K++, K, K--

pion and kaon rapidity distributions become slightly narrowerpion and kaon rapidity distributions become slightly narrower


0.0 0.2 0.4 0.6 0.8 1.0

10-2

10-1

100

101

102

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104

0.0 0.2 0.4 0.6 0.8 1.0

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40 A GeV, 7%

K*0.1

K+

HSD PHSD

80 A GeV, 7%

K*0.1

K+

Pb+Pb, mid-rapidity

158 A GeV, 5%

mT-m

0 [GeV] m

T-m

0 [GeV]m

T-m

0 [GeV]

K*0.1

K+

1/m

T d

N/d

mTdy

[(G

eV)-2

]

PHSD: Transverse mass spectra at SPS / NICAPHSD: Transverse mass spectra at SPS / NICA

Central Pb + Pb at SPS energiesCentral Pb + Pb at SPS energies

PHSD gives harder spectra and works better than HSD at top SPS (and top PHSD gives harder spectra and works better than HSD at top SPS (and top NICA) energies NICA) energies However, at low SPS (and low NICA) energies the effect of the partonic However, at low SPS (and low NICA) energies the effect of the partonic phase is NOT seen in rapidity distributions and mphase is NOT seen in rapidity distributions and mTT spectra spectra


Rapidity distributions of strange baryonsRapidity distributions of strange baryons

PHSDPHSD similar to HSD, reasonable agreement with datasimilar to HSD, reasonable agreement with data

-3 -2 -1 0 1 2 30

5

10

15

20

-3 -2 -1 0 1 2 3 -3 -2 -1 0 1 2 3

HSD PHSD


+0

NA49


NA49, 5%


Pb+Pb

yyy

dN/d

y

-3 -2 -1 0 1 2 30.0

0.5

1.0

1.5

2.0

-3 -2 -1 0 1 2 3 -3 -2 -1 0 1 2 3


NA49


HSD PHSD

NA49, 5%


Pb+Pb

yyy

dN/d

y


Rapidity distributions of (multi-)strange antibaryonsRapidity distributions of (multi-)strange antibaryons

enhanced production of (multi-) strange anti-baryons in PHSDenhanced production of (multi-) strange anti-baryons in PHSD

-3 -2 -1 0 1 2 30.0

0.5

1.0

1.5

2.0

2.5

-3 -2 -1 0 1 2 3 -3 -2 -1 0 1 2 3

_ _


NA49


HSD PHSDNA49, 5%


Pb+Pb

yyy

dN/d

y

-3 -2 -1 0 1 2 30.0

0.1

0.2

0.3

0.4

-3 -2 -1 0 1 2 3 -3 -2 -1 0 1 2 3


NA49


HSD PHSD


Pb+Pb

yyy

dN/d

y

strange strange antibaryonsantibaryons

_ __ _++00

multi-strange multi-strange antibaryonantibaryon

__++


Centrality dependence of (multi-)strange (anti-)baryonsCentrality dependence of (multi-)strange (anti-)baryons

enhanced production of (multi-) strange antibaryons in PHSDenhanced production of (multi-) strange antibaryons in PHSD

strange strange antibaryonsantibaryons

_ __ _++00

multi-strange multi-strange antibaryonantibaryon

__++

0 100 200 300 4000.00

0.01

0.02

0.03

0.04

0.05

0.06

0 100 200 300 4000.000

0.002

0.004

0.006

0.008

0.010

NA57NA49

HSD PHSD

+0

NwoundN

wound

Pb+Pb, 158 A GeV, mid-rapidity _ _

dN/d

y | y=

0 / N

wou

nd

0 100 200 300 40010-4

10-3

10-2

0 100 200 300 400

10-4

10-3

HSD PHSD

NA57 NA49

dN

/dy

| y=0 /

Nw

ound

Pb+Pb, 158 A GeV, mid-rapidity

Nwound

Nwound

multi-strange multi-strange baryonbaryon

--

strange strange baryonsbaryons++00


Number of s-bar quarks in hadronic and partonic matterNumber of s-bar quarks in hadronic and partonic matter

significant effect on the production of (multi-) strange antibaryons due significant effect on the production of (multi-) strange antibaryons due to a to a slightly enhanced s-sbar pair production in the partonic phaseslightly enhanced s-sbar pair production in the partonic phase from from massive time-like gluon decay and a larger formation of antibaryons in the massive time-like gluon decay and a larger formation of antibaryons in the hadronization process!hadronization process!

0 5 10 15 20 25 30 35 400

2

4

6

8

10

12

HSD PHSD

s-quarks in antibaryons

time [fm/c]

Pb+Pb, 158 A GeV, b=0.5 fm N

(ti

me)

Number of s-bar quarks in antibaryons for central Pb+Pb collisions at Number of s-bar quarks in antibaryons for central Pb+Pb collisions at 158 A GeV from PHSD and HSD158 A GeV from PHSD and HSD


What is the matter at NICA ?!What is the matter at NICA ?!

The phase trajectories ((t),(t)) for a central cell in central Au+Au collisions:

huge energy and baryon densities are reached ( >crit=1 GeV/fm3) at FAIR energies (> 5 A GeV), however, the phase transition might be NOT a cross-over at FAIR or NICA!

J. Randrup et al., CBM Physics Book; J. Randrup et al., CBM Physics Book; PPRRC75C75 (2007) (2007) 034902034902

1st order phase transition with a critical point?

co-existance of partonic and hadronic degrees of freedom (in a mixed phase)?

Summary Summary

• Some eSome exp. data are not well reproduced in terms of the hadron-string xp. data are not well reproduced in terms of the hadron-string picture => evidence forpicture => evidence for nonhadronic degrees of freedom nonhadronic degrees of freedom

•PHSDPHSD provides a consistent description of provides a consistent description of off-shell parton dynamics off-shell parton dynamics in in line with lattice QCDline with lattice QCD; the repulsive mean fields generate transverse flow ; the repulsive mean fields generate transverse flow

• The Pb + Pb data at The Pb + Pb data at top SPS energiestop SPS energies are rather well described are rather well described within PHSD including within PHSD including baryon stoppingbaryon stopping, , strange antibaryon strange antibaryon enhancementenhancement and and meson mmeson mTT slopes slopes (will be also seen at top NICA (will be also seen at top NICA

energies)energies)

• At low SPS / At low SPS / NICA energiesNICA energies PHSD gives practically the same results PHSD gives practically the same results as HSD as HSD (except for strange antibaryons)(except for strange antibaryons) when the lQCD EoS (where the when the lQCD EoS (where the phase transition is always a cross-over) is used phase transition is always a cross-over) is used

IsIs the matter at NICA a ‚mixed phase‘ of hadrons and partons?the matter at NICA a ‚mixed phase‘ of hadrons and partons?

Open problemsOpen problems

• Is the Is the criticalcritical energy/temperatureenergy/temperature provided by the provided by the lQCD calculations lQCD calculations sufficiently accurate?sufficiently accurate?

• How to describe a How to describe a first-order phase transitionfirst-order phase transition in in transport ?transport ?

• How to describe How to describe parton-hadron interactions in a parton-hadron interactions in a ‚mixed‘ phase‚mixed‘ phase??

HSD & PHSD Team

HSD & PHSD Team Wolfgang CassingWolfgang CassingOlena LinnykOlena LinnykVolodya KonchakovskiVolodya Konchakovski

Viatcheslav D. ToneevViatcheslav D. Toneev and the numerous experimental and the numerous experimental friends and colleagues !friends and colleagues !

Thanks Thanks

Documents

Parton-Hadron-String-Dynamics at NICA energies Elena Bratkovskaya Institut für Theoretische Physik, Uni. Frankfurt Round Table Discussion IV: Round Table