bulk properties of qcd matter

1/62 XXIII Graduate Days, Heidelberg, 5 9 Oct, 2009 Kai Schweda

Bulk Properties of QCD Matter

Kai Schweda, University of Heidelberg / GSI Darmstadt

Many thanks to organizers !


Outline

Introduction

Hadron Abundances - Tch

Collective Flow - Tfo,

Heavy Quarks - open charm and

quarkonia

XXIII Graduate Days, Heidelberg, 5 9 Oct, 2009 Kai Schweda

Introduction


Source: Michael Turner, National Geographic (1996)

Quark Gluon Plasma:

(a) Deconfined and

(b) thermalized state of quarks and gluons

Study partonic EOS at RHIC and LHC(?) Probe thermalization using heavy-quarks

Quark Gluon Plasma


Nuclear phase diagram

1) Heavy quarks with ALICE at LHC:- Study medium properties - pQCD in hot and dense environment

1) FAIR/GSI program:- Search for the possible phase boundary.- Chiral symmetry restoration

Energy scan


Colliding Heavy Nuclei


High-Energy Nuclear Collisions

PCM & clust. hadronization

NFD

NFD & hadronic TM

PCM & hadronic TM

CYM & LGT

string & hadronic TM

1) Initial condition: 2) System evolves: 3) Bulk freeze-out

-Baryon transfer - parton/hadron expansion - hadronic dof

- ET production - inel. interactions cease:

-Partonic dof particle ratios, Tch, B

- elas. interactions cease

Particle spectra, Tth, <T>

Time

Plot: Steffen A. Bass, Duke University


Collision Geometry

x

z

Non-central Collisions

Au + Au sNN = 200 GeV

Uncorrected

Number of participants: number of incoming nucleons in the overlap regionNumber of binary collisions: number of inelastic nucleon-nucleon collisions

Charged particle multiplicity collision centralityReaction plane: x-z plane


Hadron Abundances


Particle Multilplicities

PHOBOS fit

HIJING BBar

Armesto et al.

AMPT

Eskola

CGC

KLN

ASW

DPMJET-III

EHNRR

at LHC, dN/d 1000 3000

estimate energy density Theory points: HI at LHC – last call for predictions, CERN, May 2007.PHOBOS compilation: W. Busza, SQM07.

dy

dE

RT

Bj0

2

11

τπε =


EoS from Lattice QCD

1) Large increase in ε !

Large increase in Ndof:

Hadrons vs. partons

2) TC ~ 160 MeV

3) Boxes indicate max. initial

temperatures

Longest expansion

duration at LHC

Expect large partonic

collectivity at LHCZ. Fodor et al, JHEP 0203:014(02)

C.R. Allton et al, hep-lat/0204010

F. Karsch, Nucl. Phys. A698, 199c(02).

LHC ?RHICSPS


HI - Collision History

Plot: R. Stock, arXiv:0807.1610 [nucl-ex].

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Tc(ritical): quarks and gluon hadrons, Tc(ritical) = 160 MeV

Tch(emical): hadron abundancies freeze out

Tfo: particle spectra freeze out


Graphik: Max-Plack-Institut für Plasmaphysik

Wavelength and Intensity solely determined by temperature Tsolar = 5500 °C(at the sun’s surface)

Solar Spectrum


N

π

K+

K0

K-

N

E = mc2 (GeV)

Te

ilch

enh

äu

figke

it

0.4 0.80 1.61.2

0.1

1.0

10.0

100.

1000 Lichtquelle Teilchenquelle

Häufigkeit von Teilchen am

besten beschrieben durch

T = 2 000 000 000 000 C

= 2 Trillionen C

100 000 mal heisser

als im Innern der Sonne !

Wie heiss ist die Quelle ?


Chemical Freeze-out Model

Hadron resonance ideal gas

Compare particle ratios to experimental data

Qi : 1 for u and d, -1 for u and d

si : 1 for s, -1 for s

gi : spin-isospin freedom

mi : particle mass

All resonances and unstable particles are decayed

Refs. J.Rafelski PLB(1991)333P. Braun-Munzinger et al., nucl-th/0304013

Tch : Chemical freeze-out temperatureq : light-quark chemical potentials : strange-quark chemical potentialV : volume term, drops out for ratios!s : strangeness under-saturation factor

Density of particle i

B = 3q S = q-s


Hadron Yield Ratios

1) At RHIC:

Tch = 160 ± 10 MeV

B = 25 ± 5 MeV

2) S = 1.

The hadronic system is thermalized at RHIC.

3) Short-lived resonances show deviations.

There is life after chemical freeze-out.

RHIC white papers - 2005, Nucl. Phys. A757, STAR: p102; PHENIX: p184;Statistical Model calculations: P. Braun-Munzinger et al. nucl-th/0304013.


A. Andronic et al., NPA 772 (2006) 167.

With increasing energy:

• Tch increases and saturates

at Tch = 160 MeV

• Coincides with Hagedorn

temperature

• Coincides with early lattice results

limiting temperature

for hadrons, Tch 160 MeV

!

B decreases, B = 1MeV at LHC

Nearly net-baryon free !

Chemical Freeze-Out vs Energy




QCD Phase Diagram


Baryon Ratios

Compilation: N. Xu

With increasing energy:

• Baryon ratios approach unity

• At LHC, pbar / p 0.95

with increasing

collision energy,

production of matter

and anti-matter gets

closer


‘Elementary’ p+p Collisions

Low multiplicities

use canonical ensemble:

Strangeness locally

conserved!

particle yields are well

reproduced

Strangeness not

equilibrated ! (s =

0.5)

Statistical Model Fit: F. Becattini and U. Heinz, Z. Phys. C 76, 269 (1997).







Tch(emical): hadron abundancies freeze out, Tch(emical) = 160 MeV

Tfo: particle spectra freeze out


Collective Flow


Pressure, Flow, …Pressure, Flow, …

pdVdUd +=στThermodynamic identity

σ – entropy p – pressureU – energy V – volumeτ= kBT, thermal energy per dof

In A+A collisions, interactions among constituentsand density distribution lead to: pressure gradient collective flow

number of degrees of freedom (dof) Equation of State (EOS) cumulative – partonic + hadronic


Momentum Distributions*Momentum Distributions*2

][(

GeV

/

2c)

-1

dydp

Nd

Tπ

][GeV/ cpT

π

K (dE/dx)

p

K (kink)

*Au+Au @130 GeV, STAR

Tth=107±8 [MeV]

<t>=0.55±0.08 [c]

n=0.65±0.09

2/dof=106/90

solid lines: fit range

• Typical mass ordering in inverse slope from light π to heavier

• Two-parameter fit describes yields of

π, K, p,

• Tth = 90 10 MeV

• <t> = 0.55 0.08 c

Disentangle

collective motion from thermal random walk

π

K (dE/dx)

p

K (kink)


(anti-)Protons From RHIC (anti-)Protons From RHIC Au+Au@130GeVAu+Au@130GeV

Mor

e ce

ntra

l col

lisio

ns

22 masspm TT +=Centrality dependence:

- spectra at low momentum de-populated, become flatter at larger momentum

stronger collective flow in more central coll.!STAR: Phys. Rev. C70, 041901(R).


Thermal Model + Radial Flow Thermal Model + Radial Flow FitFit

Source is assumed to be:

– in local thermal equilibration: Tfo

– boosted in transverse radial direction: = f(s)

random

boostedE.Schnedermann, J.Sollfrank, and U.Heinz, Phys. Rev. C48, 2462(1993)

€

Ed3N

dp3∝ e−(uμ pμ )/T fo p

σ

∫ dσ μ ⇒

dN

mT dmT

∝ rdrmTK1

mT cosh ρ

Tfo

⎛

⎝ ⎜ ⎜

⎞

⎠ ⎟ ⎟0

R

∫ I0

pT sinh ρ

Tfo

⎛

⎝ ⎜ ⎜

⎞

⎠ ⎟ ⎟

ρ = tanh−1 βT βT = β S

r

R

⎛

⎝ ⎜

⎞

⎠ ⎟α

α = 0.5, 1, 2


D-meson collective flow

Large collective flow

velocity

Spectrum moves to

larger momentum







Tch(emical): hadron abundancies freeze out, Tch(emical) = 160 MeV

Tfo: particle spectra freeze out, Tfo 100 MeV :π, K, p


1) Multi-strange hadrons 1) Multi-strange hadrons and and freeze-out earlier freeze-out earlier than (than (ππ, , KK, , pp))

Collectivity prior to Collectivity prior to hadronization hadronization

2) Sudden single freeze-out*:2) Sudden single freeze-out*:Resonance decays lower TResonance decays lower Tfofo

for (for (ππ, , KK, , pp)) Collectivity prior to Collectivity prior to

hadronizationhadronization

Partonic Partonic Collectivity ?Collectivity ?

Kinetic Freeze-out at RHIC

STAR Data: Nucl. Phys. A757, (2005 102),

*A. Baran, W. Broniowski and W. Florkowski, Acta. Phys. Polon. B 35 (2004) 779.

STAR Preliminary

Anisotropy Parameter v2

y

x

py

px

coordinate-space-anisotropy momentum-space-anisotropy

€

ε =⟨y 2 − x 2⟩⟨y 2 + x 2⟩

v2 = cos2ϕ , ϕ = tan−1(py

px

)

Initial/final conditions, EoS, degrees of freedom


v2 in the Low-pT Region

P. H

uovinen, private

communications, 2004

- v2 approx. linear in pT, mass ordering from light π to heavier characteristic of hydrodynamic flow ! sensitive to equation of state


Non-ideal Hydro-dynamics

€

s

< 6 /4π

M.Luzum and R. Romatschke, PRC 78 034915 (2008); P. Romatschke, arXiv:0902.3663.

finite shear viscosity reduces elliptic flow

many caveats, e.g.:- initial eccentricity ε (Glauber, CGC, …)- equation of state- hadronic contribution to /s

String theory predicts:

/s > 1/4π


Elliptic Flow vs Collision Energy

QuickTime™ and a decompressor


Centrality dependence:

- initial eccentricity ε- overlap area S

Collision energy dep.:

- multiplicity density dNch/dy

in central collisions at RHIC, hydro-limit seems reached !

NA49, Phys. Rev. C68, 034903 (2003);STAR, Phys. Rev. C66, 034904 (2002);Hydro-calcs.: P. Kolb, J. Sollfrank, and U. Heinz, Phys. Rev.C62, 054909 (2000).

Glauber initial conditions


v2 of and multi-strange

Strange-quark flow - partonic collectivity at RHIC !

QM05 conference: M. Oldenburg; nucl-ex/0510026.


Collectivity, Deconfinement at RHIC

- v2, spectra of light hadrons and multi-strange hadrons - scaling with the number of constituent quarks

At RHIC, it seems we have:

Partonic Collectivity

Deconfinement

Thermalization ?

PHENIX: PRL91, 182301(03) STAR: PRL92, 052302(04)

S. Voloshin, NPA715, 379(03)Models: Greco et al, PRC68, 034904(03)X. Dong, et al., Phys. Lett. B597, 328(04).….


Collectivity Energy Dependence

Collectivity parameters <T>

and <v2> increase with

collision energy

strong collective

expansion at RHIC !

<T>RHIC 0.6

expect strong partonic

expansion at LHC,

<T>LHC 0.8, Tfo Tch



K.S., ISMD07, arXiv:0801.1436 [nucl-ex].


Partonic Collectivity at RHIC

1) Copiously produced hadrons freeze-out π,K,p: Tfo = 100 MeV, T = 0.6 (c) > T(SPS)

2) Multi-strange hadrons freeze-out: Tfo = 160-170 MeV (~ Tch), T = 0.4 (c)

3) Multi-strange v2: and multi-strange hadrons and do flow!

4) Model - dependent /s: (0?),1 - 10 x 1/4π

Deconfinement &Partonic (u,d,s) Collectivity !


Heavy Quarks


Heavy flavor: a unique probe

X. Zhu, M. Bleicher, S.L. Huang, K.S., H. Stöcker,N. Xu, and P. Zhuang, PLB 647 (2007) 366.

mc,b >> QCD : new scale

mc,b const., mu,d,s ≠ const.

• initial conditions:σσtest pQCD, R, F

probe gluon distribution

• early partonic stage: diffusion (), drag (), flowprobe thermalization

• hadronization:chiral symmetry restorationconfinementstatistical coalescenceJ/ enhancement / suppression

Q2

time

€

cc

€

bb


Limitations in PDFs

Most charm created from

gluons, e.g. g+g c + cbar

increasing uncertainties in gluon

distribution at smaller Bjorken x:

Assume y=0, pT=0, x1=x2

2 x mcharm 3 GeV

RHIC (s=0.2TeV): x = 0.015

LHC (s=14TeV): x = 2x10-4


Heavy Quark Production

(i) Heavy-quarks abundantly produced at LHC energies !

(ii) Large theoretical uncertainties energy scan (LHC,FAIR) will

help ! Plots: R. Vogt,Eur. Phys. J. C, s10052-008-0809-x (2008).

Heavy-quark production at LHC, compared to RHIC expect factors

Charm 10

Beauty 100


Heavy quark Correlations c-cbar mesons are correlated

• Pair creation: back to back

• Gluon splitting: forward

• Flavor excitation: flat

Exhibits strong correlations !

Baseline at zero:

clear measure of

vanishing correlations !

probe thermalization

among partons !

PYTHIA: p + p @ 14 TeV

X. Zhu, M. Bleicher, S.L. Huang, K.S., H. Stöcker,N. Xu, and P. Zhuang, PLB 647 (2007) 366.G. Tsildeakis, H. Appelshäuser, K.S., J. Stachel, arXiv: 0908.0427.


How to measure Heavy-Quark Production



e.g., D0, cτ = 123 m

displaced decay vertex is signature of heavy-quark decay

need precise pointing to collision vertex


Heavy Flavor production at RHIC

large discrepancy between STAR and PHENIX: factor > 2 (!)

need Si-vertex upgrades(> 2011)

large theoretical uncertainties (factor > 10)

Measure charm production at RHIC, LHC, FAIR and provide input to theory: - gluon distribution,

- scales R, FPlot: J. Dunlop (STAR), QM2009, Open Heavy-flavor in heavy-ion collisions, Calcs: R. Vogt,Eur. Phys. J. C, s10052-008-0809-x (2008),M. Cacciari, 417th Heraeus Seminar, Bad Honnef (2008).


Where does all the charm go?

D0

D

Ds

c

J

Total charm cross section: open charm hadrons,

e.g. D0, D*, c, … or c,b e() + X

Hidden-charm mesons, e.g. J/ carry ~ 1 % of total charm

Statistics plot: H. Yang and Y. Wang, U Heidelberg.


Plot: A. Shabetai

D0 π+ + K- Reconstruction

D0, cτ= 123 m

π+

K-


Measure secondary decay vertex

Direct reconstruction of D0

address heavy-quark production with

1st year of data taking

Many other channels, e.g. D+, D*

Also: single-electrons from heavy-flavor

decays

Open Charm Performance

ALICE: PPR.vol.II, J. Phys. G 32 (2006) 1295.

Simulation: 109 p+p, 108 p+Pb, 107 Pb+Pb collisions


D* meson Identification

Qu

ickTim

e™

and

aTIF

F (

Uncom

pre

ssed

) de

com

pre

sso

rare

ne

ed

ed

to s

ee t

his

pic

ture

.

D*± analysis: Yifei Wang, Ph.D. thesis, University of Heidelberg, in preparation.

D*+ D0 + π+

Identify D*+

through

M[D*+ - D0]

Subtract resonance

decay to D0

Two different

methods to address

total charm

production


Viele neue interessante Signale in ALICE bei LHC:

z.B.

Hadronen mit schweren Quarks

(charm und beauty)

D0, D+, D*, Ds, J/’,c b


Quarkonia


Charmonium

Bound state of charm- and anti-charm quark

Hidden-charm meson

mJ/ = 3.1 GeV, rJ/ = 0.45 fm, mJ/' = 3.6 GeV, JP = 1- states

Minimum formation time τ = rJ/ / c = 0.45 fm

Charm-quark production at time scale tc~ 1/2mc 0.08 fm

Separation between initial production and hadronization (factorization)


Debye Screening


Quarkonia as a Thermometer

Check for melting of bottomonium (b-bbar)

at Tdeconfined 2 Tc

Check for melting of charmonium (c-cbar)

at Tdeconfined 1.2 Tc

Absolute numbers model-dependent Tfo:


J/ Production

suppression,compared to scaled p+p

regeneration,enhancement

Low energy (SPS): few ccbar quarks in the system suppression of J/

High energy (LHC): many ccbar pairs in the system enhancement of J/

Signal of de-confinement + thermalization of light

quarks !

(SPS)

P. Braun-Munzinger and J. Stachel, Nature 448 (2007) 302.


Statistical Hadronization of Charm

large charm production at LHC

strong generation of J/

striking centrality dependence

Signature for QGP

formation !

Initial conditions at LHC ?

Need to measure total

charm production in PbPb

!

Assumes kinetic

equilbration of charm !

σcc

A. Andronic, P. Braun-Munzinger, K. Redlich, J. Stachel, Phys. Lett. B 652 (2007) 259.


Charmonium production

In central Pb+Pb collisions at

top SPS energy:

J/’ to J/ ratio approaches

thermal limit

Indicates kinetic equilibration of

charm


Examples of the ALICE physics potential

- Open charm: D0 K- + π+ (already shown)

- Quarkonia: J/,

- Global event properties

Will be addressed in first year of pp collisions


First Physics with ALICE

Results from simulations 1 day of data taking Address:

- multiplicity- mean transverse momentum- hadro-chemistry


Charmonia via Di-Electron Measurement

• electron ID with TPC and TRD• expect 2500 mesons per Pb+Pb year

with good mass resolution and S/B

Simulation: 2·108 central PbPb collisions

J/

c1 c2

Simulation: pp coll.


Heavy Flavor in Muon Channel

• muon channel: J/, +- (2.5 << 4) 60000 J/ and 2000

• initial sample sufficient to study production rates of J/ and states in muon channel

J/

b


LHC: Schedule

Nov 2009: 1st pp collisionsvery short run at 900 GeV

Long run of pp collisions at 7- 10 TeV

end of 2010: 3 - 4 weeks Pb+Pb collisions at 2.8 - 3.9 TeV

*short technical stop over Christmas period


ALICE Ready for Physics !

bulk properties of qcd matter

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