Space-time Evolution of A+A collision

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2 Time Space-time Evolution of A+A collision Jets Fluctuations p p K K0* f g e m Hadronization (Freeze-out) + Expansion Mixed phase? QGP phase Thermalization Space (z) A Pre-equilibrium A Hadrons reflect the bulk property of collision system and its evolution. Jets carry information at the early stage of the evolution.

3 fm ~0 ~1 ~5 10 MeV QGP de T /dy, dn/dy , Jet Quenching -- Jet energy loss -- Jet leading baron J/y Suppression --- Debye screening + absorption -- J/y Chiral transition vector meson (r,w,f) lepton-pair Charm/bottom - initial+thermal(?) - Thermal radiation

4 de T /dy, dn/dy Bjorken s formula (scaling dn B /dy

5 dn/dy, de T /dy

6 e 0 = 0.11 A a-2/3 ln[ s /2m p ] QGP RHIC LHC QGP

7 PHENIX Background - combinatorial background

8 dn ch /dh ~ 609±1±37-5 Au+Au E NN = 130 GeV dn ch /d ~ E NN = 17.2 GeV

9 pseudo-rapidity distributions dn ch /dh (dn ch /dh)/(_n part ) %s h Data Data PHOBOS has really fantastic h coverage when wounded nucleon model is divided out, there is still an increase at mid-rapidity evidence for some relative decrease in dn ch /dh at high h Systematic error ±(10%-20%)

10 dn ch /dh ~ 609±1±37-5 E NN = 130 GeV dn/dh = A N part + B N coll Hard processes increase with centrality (30% mid-central to ~50% most central) Pb+Pb@CERN-SPS dn ch /d ~ E NN = 17.2 GeV

11 PbSc Calorimeter h f h f è

12 EMCal 1 GeV/c MIP + p 0

13 dn CH /d /dh de T /dh Np number of participants Ncoll number of binary collisions centrality (30% in mid-central ~50% in most central) dx d = A N + B h h=0 part N coll PHENIX preliminary A = 0.88 ± 0.28 B = 0.34 m 0.12 B / A = 0.38 ± 0.19 A = 0.80 ± 0.24( GeV ) B = 0.23 m 0.09( GeV ) B / A = 0.29 ± 0.18

14 CMS dn ch /dh de T /dh

15 e ~ 5 GeV/fm 3 s = 130 AGeV e 0 = 0.11 A a-2/3 ln[ s /2m p ] Bjorken s formula e = = m pr pr T t t 0 0 dn dy de T dy

16 Model comparison 130GeV 200GeV Naïve hard&semi-hard two component model (HIJING) is excluded. High energy QCD gluon saturation model (KLN) and two-component mini-jet model with nuclear shadowing (Mini-jet) are favored. EKRT K.J.Eskola et al, Nucl Phys. B570, 379 and Phys.Lett. B 497, 39 (2001) HIJING X.N.Wang and M.Gyulassy, PRL 86, 3498 (2001) KLN D.Kharzeev and M. Nardi, Phys.Lett. B503, 121 (2001) D.Kharzeev and E.Levin, Phys.Lett. B523, 79 (2001) Mini-jet S.Li and X.N.Wang Phys.Lett.B527:85-91 (2002)

17 freeze-out Radial flow freeze-out Elliptic flow Hydro-dynamic flow model

18 Radial Flow

19 TOF TOF = L v = LE p = L p 2 p + m 2 m = p Ê Á Ë TOF L ˆ 2-1

20 Particle ID Techniques de/dx RICH s (de/dx) =.08 de/dx PID range: ~ 0.7 GeV/c for K/p ~ 1.0 GeV/c for K/p RICH PID range 1-3 GeV/c for K/p GeV/c for K/p

21 STAR Particle ID Topology Secondary vertex: K s Æ p + p, LÆ p + p, XÆ L + p, WÆ L + K g Æ e + +e - Combinatorics K s Æ p + + p - f Æ K + + K - L Æ p + p r Æ p + + p - dn/dm f from K + K - pairs background subtracted m inv dn/dm K + K - pairs same event dist. mixed event dist. kinks K ± Æ m ± + n m inv

22 STRANGENESS! (Preliminary) L bar W - W + f K + K 0 s L X - X + K *

23 m T scaling E d 3 dp s 3 = m T 3 d s dm dydf T = È mt - A( y)expí- Î T m p-p p-a m T T BNL-AGS E802

24 Au+Au at BNL-AGS Au+Au at BNL-RHIC m T -mass [GeV/c 2 ]

25 BNL-AGS Only stat. errors are shown

26 Collective Expansion - Single particle p T spectra - Simultaneous fit in range (m t -m 0 ) < 1 GeV is shown. The top 5 centralities are scaled for visual clarity. Similar fits for positive particles.

27 <p T > [GeV/c] Collective Expansion - <p T > vs. N part - <p T > [GeV/c] Systematic error on 200 GeV data p (10 %), K (15 %), p (14 %) open symbol : 130 GeV data <p T > increases with N part and particle mass => radial expansion. Consistent with hydrodynamic expansion picture.

28 Radial Isotropic thermal source with raidus R b f 3 d s Ê = Aexp 3 Á - dp Ë E d 3 dp s 3 µ Ú 0 R r 2 E T ˆ Æ Ê dre exp Á - Ë 3 d s Ê E = AE exp 3 Á - dp Ë E T g È f E ˆ Ê ˆ ÍÁ T sinha T T Í ÎË g f E a g f E ˆ cosha p Isotropic Flow Model ---- K.S. Lee and U. Heinz, Z. Phys. C 43 (1989) 425. b b f S n Ê r ˆ = Á bs : flow velocity at r Ë R : velocity at R a = b f g f n : velocity profile p / T At each r: Ed 3 s/dp 3 dv = Ed 3 s/dp 3 r 2 drdw Back to rest frame: E g f (E + b f p cos q) dv dv/ g f pion proton Kaon

29 AGS Data from E866 exp. at 11.6 AGeV Au+Au central collision non-exponential shape ( b S = 0.69 (0.03) n = 0.5 (0.1) T = 91.2 (2.6) MeV

30 Radial Flow T ~ T 0 + m<b 2 > s n L m = 1 s ~ mb n = n N L m = fm n = 4 n N L m = fm L m << R (~ 7 fm), t (~ R) P(T,m) Inverse slope parameter [GeV/c 2 ] STAR ( s NN =130 GeV) mass [GeV/c 2 ] RHIC SPS

31 Result of hydrodynamic model fit Most central collisions for 200 GeV data Au+Au at sqrt(s NN ) =200GeV Freeze-out Temperature (*) T fo = 110 ± 23 MeV Transverse flow velocity (*) b T = 0.7 ± 0.2 J.M. Burward-Hoy@QM02 (*) Resonance feed down is not corrected. Ref: E. Schnedermann, J. Sollfrank, and U. Heinz, Phys. Rev. C 48, 2462 (1993) b T increases from peripheral to mid-central (N part < 150) and tends to saturate for central collisions.

32 Flow Analysis AGS