Toru Sugitate / Hiroshima Univ. ISMD31 / Sept. 4, 2001

The 31st International Symposium onMultiparticle Dynamicson 1-7, Sept. 2001

in Datong, China

Correlation and fluctuation studies at RHIC

Toru Sugitate Hiroshima University

Sugitate@hepl.hiroshima-u.ac.jp

Toru Sugitate / Hiroshima Univ. ISMD31 / Sept. 4, 2001

Multiparticle dynamics in high-energy heavy-ion collisions

Relativistic Heavy Ion Collider (RHIC) begins smashing atoms at sNN = 200 GeV.

Experiments will yield insights into the structure of matter and how the universe evolved.

Understand the non-pertuabative QCD nature; multiparticle dynamics of deconfined quarks and gluons in Quark-Gluon-Plasma, which probably existed in the early Universe.

Te

mp

era

tur

e

Baryon densityNormalNucleus

Hadronic Matter

Quark-Gluon Plasma

quark confinement

Chiral symmetry

Toru Sugitate / Hiroshima Univ. ISMD31 / Sept. 4, 2001

222TO

2TO

2TS

2TS

2L

2L2 RqRqRqexp1C

expTOR

In the Longitudinal Center of Mass System (p1z+p2

z=0);

2expTS

2expTO

22pair RR

It is obvious for a static source, but our source is expanding..

2

2

2TO

2TO

2TS

2TS

2L

2L

2

t

R2

r

R2

r

R2

rexpt,r

Particle correlations – a tool to pin down the phase transition

In the 1st order phase transition, matter of the mixed phases stops expansion due to the softening of Equation of State.

Consequently a prolonged lifetime of particle emission is expected.

T

B

TC

QGP

Toru Sugitate / Hiroshima Univ. ISMD31 / Sept. 4, 2001

The STAR (Solenoidal Tracker at RHIC) experiment at RHIC

K p d

e

STAR STAR AcceptancAcceptanc

ee

A large volume TPC covers || < 1 with a full azimuthal coverage.

PID capability of TPC - dE/dx and RICH. Topological PID technique for short lived and/or ne

utral particles.

Toru Sugitate / Hiroshima Univ. ISMD31 / Sept. 4, 2001

The PHENIX (Pioneering High Energy Nuclear Interaction eXperiment) at RHIC

Broadest possible study of A-A, p-A, p-p collisions tostudy nuclear matter under extreme conditions using a wide

variety of probes sensitive to all timescales, i.e., hadrons, electron, muons, and photons as many potential signatures of QGP as possible, and

study systematic variations with species and energy. Measure spin structure of the nucleon.

Toru Sugitate / Hiroshima Univ. ISMD31 / Sept. 4, 2001

Negative pion correlation studies in STAR and PHENIX

STAR published in PRL 87(2001)082301

PHENIX preliminary for QM01

Q (

MeV/c)

Q Long

Q ( MeV/

c)

Q ( MeV/

c)

Q Side Q Out

C 2 (Q

; Qot

hers<

80 M

eV/c

)First particle correlation data at RHIC. Consistent between two experiments. Positive pions show similar results.No surprise with the C2 functions.

12-15% most central events in Au+Au at sNN=130 GeV.Negative pions in the mid-rapidity.3 dimensional analysis in the LCMS frame.

Toru Sugitate / Hiroshima Univ. ISMD31 / Sept. 4, 2001

s dependence of source size parameters viewed by negative pions

No significant rise or jump from AGS to RHIC. Parameters are quite similar to those at SPS.Transverse radii seems to be constant.Longitudinal radius increases as s.

sNN (GeV)

101 100

Rou

t/Rsi

de

0

1.5

0.5

1

4

2

(R

out2 -R

side

2 )

E895 NA44 NA49 PHENIXE866 WA98 STAR

sNN (GeV)101 100

Rou

t (fm

)R

side

(fm

)

8

4

6

8

4

6

8

4

6

2

1

0.4

0.8

1.2

0.6

Rlo

ng (f

m)

No remarkable difference between Rout and Rside. is similar to those at SPS/AGS.No indication of a long-lived mixed phase.

Toru Sugitate / Hiroshima Univ. ISMD31 / Sept. 4, 2001

Centrality and mT dependences of the source size parameter

STAR published data in PRL87 (2001)082301

1.0

0.4

0.8

1.2

0.6

+ -

0.2med highlowcentrality bin mT (GeV/c2)

0.3 0.4

Rou

t (fm

) 8

4

6

Rsi

de (f

m) 8

4

6

8

4

6

2

Rlo

ng (f

m)

+ and - show same dependences.’s do not change with multiplicity, but R’s increase with centrality.

consistent with native expectation of geometrical size.

’s increase, but R’s decrease as mT. consistent with a hypothesis of hydrodyna

mical expanding sources.

NA44 published in PRL 87(2001)112301

R=3.0 / mT

+ -

0.2med highlowcentrality bin mT (GeV/c2)

0.3 0.4

Rou

t (fm

) 8

4

6

Rsi

de (f

m) 8

4

6

8

4

6

2

Rlo

ng (f

m)

Does the mT scaling observed at SPS explain the present RTrans and RLong data at RHIC ?

Toru Sugitate / Hiroshima Univ. ISMD31 / Sept. 4, 2001

Fluctuations – a tool to pin down the phase transition

Fluctuation of locally conserved quantities; net baryon number, electric charge, strangeness prove the quark de-confinement phase.

O

OOO T)(222

T)(

T)(

Tre

eTrO

OOO

H

H

014.0S/)N(

033.0S/)N(2QGP

b

2HGb

036.0S/)Q(

06.0S/)Q(2QGP

2HG

The Net Baryon number in hadron gas

)Tcosh()0,T(N2)N(

e)0,T(N),T(N

b2HGb

Tbb

The net Baryon number in a QGP with 2 massless flavor

2

32QGPb T3

11T

9

2)N(

V

1

M. Asakawa presented in QM01;

Then, we should see difference in;

and

Toru Sugitate / Hiroshima Univ. ISMD31 / Sept. 4, 2001

Event-by-event fluctuations in the mean Pt in PHENIX

Centrality: 0-5%

PHENIX Preliminary

<Pt> (GeV/c)

Data vs. Mixed Event <Pt> (GeV/c)

<Pt> , Central Collisions

Note: This is not a fit!

by J. Mitchell　 (BNL) for the ACS on 8/30/01

Gamma Distribution Calculation

M. Tannenbaum, Phys. Lett. B498 (2001) 29.

Toru Sugitate / Hiroshima Univ. ISMD31 / Sept. 4, 2001

Event-by-event fluctuations in the mean Et in PHENIX

Mean Max Simulation Centrality: 0-5%

PHENIX Preliminary

PbSc <Et> (GeV)

<Et> , Central Collisions

by J. Mitchell　 (BNL) for the ACS on 8/30/01

Simulation for statistically independent emission incl. experimental biases.

Toru Sugitate / Hiroshima Univ. ISMD31 / Sept. 4, 2001

Summary and outlook of correlation and fluctuation studies at RHIC

The source size parameters at sNN = 130 GeV are similar to those at SPS/AGS. The duration time is consistent with zero, similar to those at SPS/AGS. No indications of a huge source formation or a prolonged mixed phase. No significant non-statistical fluctuations in <pT> and <ET> were seen by PHENIX, b

ut some indication in charge independent <pT> by STAR.

Why all the source sizes are almost constant in about two orders of s? No QGP’s? What controls the source size parameters?

Why the mT scaling at SPS explains the radii at RHIC? Is there any universal scaling on s? Another hint; RLong ~ RTrans at both SPS and RHIC.

Why almost no duration time during pion emissions? Did hydrodynamical flow wash out the signals?

Look at Au+Au at sNN = 200 GeV. Study the correlation functions by other particle species. Study the net baryon-, charge- and strangenss-fluctuations. Event-by-Event correlation and fluctuation. Energy scan and different collision systems.

Hydrodynamic QGP fluid + hadronic re-scattering; S.Soff, A.Bass, A.Dumitru, PRL 86 (2001) 3981