Heavy - Flavor (c,b) Collectivity at RHIC and LHC

1 USTC, Hefei, Nov 22, 2005

HeavyFlavor (c,b) Collectivity

at RHIC and LHC

Kai Schweda, University of Heidelberg

A. Dainese, X. Dong, J. Faivre, Y. Lu, H.G. Ritter, L. Ruan,A. Shabetai, P. Sorensen, N. Xu, H. Zhang, Y. Zhang.


Outline

1) Introduction

2) Multi-strange baryons elliptic flow

3) Heavy-quark Collectivity

4) Summary


Quark Gluon Plasma

Source: Michael Turner, National Geographic (1996)

Quark Gluon Plasma:

(a) Deconfined and

(b) thermalized state of quarks and gluons

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


Phase Diagram


Heavy Ion CollisionsHeavy Ion 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 - interaction cease

- Partonic dof Tth, <T>

Time

Plot: Steffen A. Bass, Duke University

Heavy-Flavor , K, p

USTC, Hefei, Nov 22, 2005


The STAR Detector

Coils

Silicon Vertex Tracker

E-M Calorimeter

Trigger Barrel

Time Projection Chamber

Forward Time Projection Chamber

Electronics Platforms

Magnet


Peripheral Event

STARSTAR

Au + Au Collisions at RHICAu + Au Collisions at RHIC

(real-time Level 3)

9 USTC, Hefei, Nov 22, 2005STARSTAR

Mid-Central Event


(real-time Level 3)



STARSTAR

Central Event

(real-time Level 3)


Particle IdentificationParticle Identification

Reconstruct multi-strange resonances in 2 acceptance of STAR!


Pressure, Flow, …Pressure, Flow, …

pdVdUd Thermodynamic identity

– entropy p – pressureU – energy V – volume= 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


1) Compared to 1) Compared to , , KK, and , and p,p, multi-strange particles multi-strange particles ,, are found at lower <are found at lower <TT>>

but higher T ~ Tbut higher T ~ Tchch

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

hadronizationhadronization

Partonic Partonic Collectivity ?Collectivity ?

Kinetic Freeze-out at RHIC

Data: Data: STAR preliminary Au+Au@200GeV: Nucl. Phys. A715, 129c(2003).*A. Baran, W. Broniowski and W. Florkowski; nucl-th/0305075

STAR Preliminary

Disentangle collective flow (T) and random walk (T)


Anisotropy Parameter v2

y

x

py

px

coordinate-space-anisotropy momentum-space-anisotropy

y2 x 2

y 2 x 2v2 cos2 , tan

1(pypx)

Initial/final conditions, EoS, degrees of freedom


v2 in the Low-pT Region

P. H

uo

vi ne

n, p

r ivate

com

mu

nica

t i on

s, 20

04

- Minimum bias data! At low pT, model result fits mass hierarchy well!- Details does not work, need more flow in the model!


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).….


Partonic Collectivity at RHIC

1) Copiously produced hadrons freeze-out: 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: Multi-strange hadrons and do flow!

4) Constituent Quark scaling: Seems to work for v2 and RAA (RCP)

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


Heavy-Flavor Quarks

Plot: B. Mueller, nucl-th/0404015.

Symmetry is broken:

QCD dynamical mass

EW Higgs mass

Even in a QGP, charm and

beauty quark-mass heavy !

Heavy-flavor (c,b) are

good probes !

If heavy quarks flow:

frequent interactions

among all quarks

light quarks (u,d,s)

likely to be thermalizedPlot: B. Mueller, nucl-th/0404015.

Mas

s (M

eV/c

2 )

106

105

104

103

102

10

1


Charm-quark Elliptic Flow

V. Greco et al., PLB 595(2004)202

Coalescence approach

Large X-sec needed to reach large v2 → Charm quark flows →Indication of light flavor thermal equilibrium!Theoretical justification of the large cross section?

AMPT transport model

B. Zhang et al., nucl-th/0502056


The key point is to determine

Heavy-Flavor Collectivity


V. Greco et al.PLB 595(2004)202

B. Zhang et al.nucl-th/0502056

Non-photonic electron v2

c (b) e + X

Large syst. uncertainties due to large background

Experimental data do not agree at 2<pT(e)<5 GeV/c!

v2(e) favors non-zero v2(c) at pT(e)<2 GeV/c.


D0 Reconstruction in STAR

• D0 + K, BR = 3.8%, c = 124m

• calculate invariant mass in + K system

• Peak around 1.86 GeV/c2

• Large combinatorial background

Large stat. and syst. uncertainties

Need precise track information !

Need precise pointing device !

Central Au + Au collisions in STAR

TPC only


STAR Detector Upgrade

• D0 K + c = 123m

• Measure decay vertex,

50m

• enhance S/B by factor 100

precise heavy-flavor

measurements !

Full Barrel MRPC - TOF Heavy Flavor Tracker

Active Pixel Sensors: M. Winter et al., IReS/LEPSI, Strasbourg.


Flow Measurements

• Au + Au, 50M central events

• D0 K +

• Expected statistical

uncertainties small

Probe charm quark flow !

Also: Measure Ds +

D0 simulations: A. ShabetaiD0 v2-predictions: D. Molnar, J. Phys. G31, S421.


The Alice Detector @ LHC

TPC: main tracking device

ITS: high spatial resolution

TRD: good electron PID (high pion rejection)

ToF: extend PID to large pT


ALICE @ LHC : D0 K-+

|y| < 1 and pt > 1 GeV/c • Pb + Pb central, 1st year

• D0 K +

• Expected stat. + syst.

uncertainties small

Probe heavy-flavor flow !

D0 simulations: A. Dainese, nucl-ex/0510082.

Other (possible?) channels:

c pK (BR ~ 5%)

c K0, K+


J/Enhancement at LHC Statistical hadronization

strong centrality dependence

of J\ yield at LHC

Need total charm yields !

Measure D0, D±, c, c

Probe deconfinement

and thermalizationCalculations:P. Braun Munzinger, C. Redlich,and J. Stachel, nucl-th/0304013.


Multiply Heavy-flavored Hadrons

F. Becattini, Phys. Rev. Lett. 95, 022301 (2005);P. Braun Munzinger, C. Redlich, and J. Stachel, nucl-th/0304013.

Statistical hadronization

- de-confined heavy-quarks

- equilibrated heavy-quarks

Enhancement up to x1000 !

Measure cc, cc, Bc, (ccc)

Need total charm yields

Probe deconfinement and

thermalization

QGP !

Quarks and gluons hadrons

Pb+Pb

ccc / D :

p+p

x1000


Summary

Multi-strange hadrons and flow

Partonic collectivity at RHIC

Deconfinement at RHIC

Measure spectra, elliptic flow and yields of

D0, D, D+s, C, J/, B±

Probe (u,d,s)-quark thermalization

ALICE: TPC + Vertex + TRD (+ToF)


Building Blocks of Matter

Elementary particles –

microscopic laws:

Electroweak force

Hunt for theStrong force

Gravitation

Masses are free

parameters !

Origin of Mass ?

Heavy - Flavor (c,b) Collectivity at RHIC and LHC

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