1 First Alice Physics Week, Erice, Dec 4 9, 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.

2 First Alice Physics Week, Erice, Dec 4 9, 2005

Outline

1) Introduction

2) Multi-strange baryons and elliptic flow

3) Heavy-quark (b,c) Collectivity

4) Summary

3 First Alice Physics Week, Erice, Dec 4 9, 2005

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 in high energy nuclear collisions(?) Probe thermalization using heavy-quarks

4 First Alice Physics Week, Erice, Dec 4 9, 2005

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

5 First Alice Physics Week, Erice, Dec 4 9, 2005

Kinetic Freeze-out at RHIC

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

1) ,K and p change smoothly from peripheral to central collisions.

2) At the most central collisions, <T> reaches 0.6c.

3) Multi-strange particles , are found at higher T and lower <T>

Sensitive to early partonic stage!

What about v2 ?

4) Single sudden freeze-out*: all collectivity from partonic stage!

STAR: NPA715, 458c(03); PRL 92, 112301(04); 92, 182301(04). *A. Baran, W. Broniowski and W. Florkowski; nucl-th/0305075.

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Anisotropy Parameter v2

y

x

py

px

coordinate-space-anisotropy momentum-space-anisotropy

y 2 x 2y 2 x 2

v2 cos2 , tan 1(pypx)

Initial/final conditions, EoS, degrees of freedom

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Collectivity, Deconfinement at RHIC

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

At RHIC, I believe we have:

Partonic Collectivity

Deconfinement

Thermalization ?

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

PRL95, 122301(05).

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

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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 !

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

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Charm-quark Elliptic Flow

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

Coalescence approach

Heavy-quark collective flow observable in D-meson v2

Large partonic cross sections needed Frequent interactions Challenge to theory ?

AMPT transport modelB. Zhang et al.,PRC 72(2005) 024906.

D = (cu)

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The key point is to determine

Heavy-Flavor Collectivity

11 First Alice Physics Week, Erice, Dec 4 9, 2005

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

12 First Alice Physics Week, Erice, Dec 4 9, 2005

Heavy-flavor Energy Loss

Heavy-flavor decay electrons:

Probe interaction with medium

Induced gluon radiation only

Plus elastic collisions

Better agreement with data

Start understanding heavy flavor interaction with the medium !

Disentangle b,c by direct reconstruction of B at LHC !

Calculations: M. Djordjevic et al.

13 First Alice Physics Week, Erice, Dec 4 9, 2005

Heavy-Flavor in ALICE

TPC: main tracking device

ITS: high spatial resolution, D,B decay vertex

TRD: good electron PID (high pion rejection), J/, , B,D e

ToF: extend PID to large pT

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Heavy-Flavor in ALICE : 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+

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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, K. Redlich,and J. Stachel, nucl-th/0304013.

16 First Alice Physics Week, Erice, Dec 4 9, 2005

Multiply Heavy-flavored Hadrons

F. Becattini, Phys. Rev. Lett. 95, 022301 (2005);P. Braun Munzinger, K. 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

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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