JPS fall Meeting at Kochi University September 29, 2004 Radial Flow Study via Identified Hadron...

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JPS fall Meeting at Kochi UniversitySeptember 29, 2004

Radial Flow Study via Identified Hadron Spectra in Au+Au collisions

Akio Kiyomichi (RIKEN)for the PHENIX Collaboration

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JPS Fall Meeting, Sep.29, 2004

Akio Kiyomichi [RIKEN]2


Outline• Identified charged hadron spectra at RHIC

– pT spectra : Having the entire history of dynamical evolution of the system.

• Centrality dependence of spectra shape.• <pT > vs. particle mass, centrality.• Freeze-out temperature and expansion velocity(radial flow).

• In this presentation:– Result of identified charged hadron pT spectra in Au+Au collisions

at sNN = 200 GeV (run-2) and 130 GeV(run-1) from PHENIX.

– Freeze-out temperature and expansion velocity based on the hydro-dynamical model.

• Single particle spectra of ,K,p are described by common temperature and velocity.

– Centrality dependence, beam energy dependence.




EAST ARM

CENTRAL MAGNET + MUON ARM

BBC

TOF

DC+PC1

Charged Hadron PID

• Detectors for hadron measurement.

• DCH+PC1+TOF+BBC• = /8, -0.35 < < 0.35

• Charged Hadron PID by TOF.• 0.2< < 3.0 GeV/c • 0.4< K < 2.0 GeV/c • 0.6< p < 4.5 GeV/c




pT Spectra

Central• Low pT slopes increase with particle mass.• Proton and anti-proton yields equal the pion yield at high pT. Peripheral• Mass dependence is less pronounces.• Similar to pp.




sys. error from extrapolation x2

sys. error from cuts

Mean pT vs. Npart

• Increase from peripheral to mid-central, and then saturate from mid-central to central for all particle species.

• Observed clear mass dependence.• Indicative radial expansion. (consistent with hydro picture)

PHENIX:Phys.Rev.C69,034909(2004)Au+Au at sNN = 200 GeV




Blast-wave model Parameterization

R

f(r)

r

Ref:Sollfrank,Schnedermann,Heinz,PRC48(1993)2462.

€

1

mT

dN

dmT

= A f (r)rdrmT I0

pT sinhρ

Tfo

⎛

⎝ ⎜ ⎜

⎞

⎠ ⎟ ⎟K1

mT coshρ

Tfo

⎛

⎝ ⎜ ⎜

⎞

⎠ ⎟ ⎟0

R

∫I0 , K1: modified Bessel function

(r)

r

€

(r) = tanh−1 βT( ) ⋅r/R

(r)

Use linear flow rapidity profile and constant particle density

€

T =β (r)rdr

0

R

∫rdr

0

R

∫

Average flow velocity:

€

(r) = tanhρ (r)

Parameters: normalization A freeze-out temperature Tfo

surface velocity T

mT

1/m

T d

N/d

mT

TfoA

T




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Ç™Ç±ÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅBRatio: Tch~177MeV,B ~29MeV

Resonance:

• , K, p, anti-p

•

• K*, K*0, anti-K*0,

• , ,anti-

1. Generate resonances with pT distribution determined by each combinations of Tfo, T.

2. Decay them and obtain pT spectra of ,K,p.

3. Particle abundance calculated with chemical parameters Tch = 177MeV, B = 29MeV (200GeV), Tch = 176MeV, B = 41MeV(130GeV)

Ref:P.Braun-Munzinger et al,PLB518(2001)41.

4. Merge and create inclusive pT spectra. 2 test

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Model fit with resonance feed down




• Minimize contribution from hard process– (mT-m0) <1GeV

: pT < 1.2GeV/c, K : pT < 1.4GeV/c,p : pT < 1.7GeV/c

• Exclude large resonance for pion at very low pT region

– : pT>0.5GeV/c

• Simultaneous fit to spectra of ,K,p– Tfo : 60~240MeV , 2MeV each

– T : 0.00~0.90, 0.01 each

• More fine mesh in small region:– Tfo : 90~130MeV , 1MeV each

– T : 0.70~0.82, 0.002 each

Fitting the pT spectra

0-5%

80-92%




2 contours in parameter space Tfo and T • Upper figure show the 2 test result

of simultaneous fitting for most-central spectra.

• Lower figure show 2 contours for each particles.

• There are strong anti-correlation between Tfo and T.

PHENIX Au+Au most central:– 200GeV: Tfo = 108MeV, <T> = 0.57

– 130GeV: Tfo = 134MeV, <T> = 0.48

0-5%:most central




The 3 contour levels are shown in each centrality.

• Npart dependence of expansion is observed:– @central: saturate

– @peripheral : Npart 0, Tfo increase, <T> 0

Centrality dependence of Tfo and <T>




Conclusion• Results of identified charged hadron spectra.

– Au+Au 130GeV: Phys.Rev.C69 024904(2004)– Au+Au 200GeV: Phys.Rev.C69 034909(2004)

• Hydro-dynamical model fit to the spectra with resonance decay effect.– Npart dependence of expansion is observed

• @central : saturate

• @peripheral Npart 0 :Tfo increase, <T> 0

– For the most central: • Au+Au 200GeV: Tfo = 108MeV, <T> = 0.57

• Au+Au 130GeV: Tfo = 134MeV, <T> = 0.48

Next Step• for Au+Au 62.4GeV, p+p 200GeV




USA Abilene Christian University, Abilene, TXBrookhaven National Laboratory, Upton, NYUniversity of California - Riverside, Riverside, CAUniversity of Colorado, Boulder, COColumbia University, Nevis Laboratories, Irvington, NYFlorida State University, Tallahassee, FLFlorida Technical University, Melbourne, FLGeorgia State University, Atlanta, GAUniversity of Illinois Urbana Champaign, Urbana-Champaign, ILIowa State University and Ames Laboratory, Ames, IALos Alamos National Laboratory, Los Alamos, NMLawrence Livermore National Laboratory, Livermore, CaUniversity of New Mexico, Albuquerque, NMNew Mexico State University, Las Cruces, NMDept. of Chemistry, Stony Brook Univ., Stony Brook, NYDept. Phys. and Astronomy, Stony Brook Univ., Stony Brook, NY Oak Ridge National Laboratory, Oak Ridge, TNUniversity of Tennessee, Knoxville, TNVanderbilt University, Nashville, TN

Brazil University of São Paulo, São PauloChina Academia Sinica, Taipei, Taiwan

China Institute of Atomic Energy, BeijingPeking University, Beijing

France LPC, University de Clermont-Ferrand, Clermont-FerrandDapnia, CEA Saclay, Gif-sur-YvetteIPN-Orsay, Universite Paris Sud, CNRS-IN2P3, OrsayLLR, Ecòle Polytechnique, CNRS-IN2P3, PalaiseauSUBATECH, Ecòle des Mines at Nantes, Nantes

Germany University of Münster, MünsterHungary Central Research Institute for Physics (KFKI), Budapest

Debrecen University, DebrecenEötvös Loránd University (ELTE), Budapest

India Banaras Hindu University, BanarasBhabha Atomic Research Centre, Bombay

Israel Weizmann Institute, RehovotJapan Center for Nuclear Study, University of Tokyo, Tokyo

Hiroshima University, Higashi-HiroshimaKEK, Institute for High Energy Physics, TsukubaKyoto University, KyotoNagasaki Institute of Applied Science, NagasakiRIKEN, Institute for Physical and Chemical Research, WakoRIKEN-BNL Research Center, Upton, NYRikkyo University, TokyoTokyo Institute of Technology, TokyoUniversity of Tsukuba, TsukubaWaseda University, Tokyo

S. Korea Cyclotron Application Laboratory, KAERI, SeoulKangnung National University, KangnungKorea University, SeoulMyong Ji University, Yongin CitySystem Electronics Laboratory, Seoul Nat. University, SeoulYonsei University, Seoul

Russia Institute of High Energy Physics, ProtovinoJoint Institute for Nuclear Research, DubnaKurchatov Institute, MoscowPNPI, St. Petersburg Nuclear Physics Institute, St. PetersburgSt. Petersburg State Technical University, St. Petersburg

Sweden Lund University, Lund

12 Countries; 58 Institutions; 480 Participants*

*as of January 2004




Au+Au 130GeV

• Simultaneous fit to spectra of ,K,p (Au+Au 130GeV)

Spare




Beam energy dependence

• Most central event of Au+Au (AGS,RHIC) or Pb+Pb (SPS)

• Radial flow: Slightly increases from <T>~0.45 (AGS) to ~0.5 (SPS), ~0.55(RHIC) .

• Temperature: 100~120MeV




• Simultaneous fit of ,K,p and . 2 contour for overlap with ,K,p.

• Seem to be common Tfo and <T>

Fit with phi meson

0-10%

K+K- to be submitted to PRC

PHENIX Au+Au sNN = 200 GeV




Fit with phiSpare

])

[(G

eV/c

21

2-2

2

dydm

Nd

mT

T

0 0.5 1 1.5 2 2.5 3

mT – mass [GeV/c2]

1

10-1

10-2

10-3

10-4

10-5

10to be submitted to PRC

PHENIX Au+Au sNN = 200 GeV

K+K-




Evidence for equilibrated final state• Almost complete reconstruction of hadronic state when system decouples by the

statistical thermal model. • Fit yields vs. mass (grand canonical ensemble)

Ø Tch = 177 MeV, B = 29 MeV @ 200 GeV central AuAu.

Spare




Inclusive pT spectra

Create inclusive pT spectra for each particles, each (Tfo , T)

Resonance:

• , K, p, anti-p

•

• K*, K*0, anti-K*0,

• , ,anti-

Spare




Tfo vs. <T>Spare

JPS fall Meeting at Kochi University September 29, 2004 Radial Flow Study via Identified Hadron...

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