Itzhak Tserruya QM05 Budapest 9/8/05 1 QM2005, August 4-9, 2005, Budapest, Hungary Itzhak Tserruya Experimental Summary and Outlook “That much accomplished, so much left to do”

Itzhak Tserruya QM05 Budapest 9/8/05 2  4 white papers  a new logo was born: perfect liquid What happened since last QM?  Most successful Run-4 and Run-5 at RHIC  All this & new results presented in 25 experimental plenary talks and 60 experimental parallel talks  I have the impossible task to summarize all of this in 40 minutes all of this in 40 minutes  87 experimental papers published in the refereed literature in the refereed literature 30 of them in PRL 30 of them in PRL Run Year Species s 1/2 [GeV ]  Ldt Au+Au  b /2 Au+Au  b -1 p+p pb /3 d+Au nb -1 p+p pb /4 Au+Au  b -1 Au+Au 62 9  b /5 Cu+Cu nb -1 Cu+Cu nb -1 Cu+Cu  b -1 p+p pb -1

Itzhak Tserruya QM05 Budapest 9/8/05 3 Global event characterization:   Global observables (dN/d , HBT, fluctuations)   Chemical and thermal Equilibrium   Flow Penetrating probes   High p T suppression   Jets   Charm and charmonium   Dileptons   Photons Last three QM conferences were dominated by: Global event characterization:  Global observables (dN/d , HBT, fluctuations)  Chemical and thermal Equilibrium  Flow Penetrating probes  High p T suppression  Jets  Charm and charmonium  Dileptons  Photons Present QM conference was dominated by:

Itzhak Tserruya QM05 Budapest 9/8/05 4 Global event characterization:   Global observables (dN/d , HBT, fluctuations)   Chemical and thermal Equilibrium   Flow Penetrating probes   High p T suppression   Jets   Charm and charmonium   Dileptons   Photons Last three QM conferences were dominated by:

Itzhak Tserruya QM05 Budapest 9/8/05 5 Global event characterization:  Global observables (dN/d , HBT, fluctuations)  Chemical and thermal Equilibrium  Flow Penetrating probes  High p T suppression  Jets  Charm and charmonium  Dileptons  Photons Present QM conference was dominated by:

Itzhak Tserruya QM05 Budapest 9/8/05 6 Cu+Cu vs Au+Au Cu+Cu vs Au+Au

Itzhak Tserruya QM05 Budapest 9/8/05 7 Cu+Cu vs Au+Au dN/d  scales with N part Au+Au 35-40%,N part = 98 Cu+Cu Preliminary 3-6%, N part = GeV Cu+Cu Preliminary 3-6%, N part = GeV Au+Au 35-40%, N part = 99 PHOBOS dN/d  PHOBOS Vary system size at same energy Elliptic flow scales with participant eccentricity PHOBOS 200 GeV Au+AuCu+Cu preliminary Scales with Participant Eccentricity Elliptic flow R AA scales with N part Same behavior for same N part but better accuracy in CuCu R AA

Itzhak Tserruya QM05 Budapest 9/8/05 8 Cu+Cu vs Au+Au dN/d  scales with N part Au+Au 35-40%,N part = 98 Cu+Cu Preliminary 3-6%, N part = GeV Cu+Cu Preliminary 3-6%, N part = GeV Au+Au 35-40%, N part = 99 PHOBOS dN/d  PHOBOS Vary system size at same energy

Itzhak Tserruya QM05 Budapest 9/8/05 9 Cu+Cu vs Au+Au Vary system size at same energy Elliptic flow scales with participant eccentricity PHOBOS 200 GeV Au+AuCu+Cu preliminary Scales with Participant Eccentricity Elliptic flow

Itzhak Tserruya QM05 Budapest 9/8/05 10 Cu+Cu vs Au+Au Vary system size at same energy R AA scales with N part Same behavior for same N part but better accuracy in CuCu R AA

Itzhak Tserruya QM05 Budapest 9/8/05 11 Cu+Cu vs Au+Au Cu+Cu vs Au+Au Vary system size at same energy  dN/d  scales with N part  Elliptic flow scales with participant eccentrincity  R AA scales with N part  Smaller system size adds significant precision at N part ≤ 100

Itzhak Tserruya QM05 Budapest 9/8/05 12 Flow Flow

Itzhak Tserruya QM05 Budapest 9/8/05 13 Every particle flows  Large v 2 of heavier particles:   d.  Even open charm flows (measured through single electrons)  Strong interactions at early stage  early thermalization.

Itzhak Tserruya QM05 Budapest 9/8/05 14 and the flow extends to very high p T

Itzhak Tserruya QM05 Budapest 9/8/05 15 Similar v 2 in Au+Au and Cu+Cu  Same flow pattern in both systems  Size of flow slightly smaller in Cu+Cu compared to Au+Au  Flow in Cu+Cu much larger than transport predictions PHOBOS 200 GeV Statistical errors only 0-40% centrality

Itzhak Tserruya QM05 Budapest 9/8/05 16 Comparison to models  Hydro works at low p T solid: STAR open: PHENIX PRL91(03)  Recombination works at intermediate p T  Also for heavier particles All this strengthens the case for sQGP with early thermalization of partonic matter made of constituent quarks

Itzhak Tserruya QM05 Budapest 9/8/05 17  Elliptic SPS  Significant v 2  CERES and NA49 in good agreement Weaker increase of v 2 (p T ) at SPS than at RHIC  Hydro with T f =120 MeV reproduce p T spectra but overpredict v 2 SPS data  Predictions with T f =160 MeV closer to v 2 data but can’t reproduce p T spectra

Itzhak Tserruya QM05 Budapest 9/8/05 18  Elliptic SPS  Significant v 2  CERES and NA49 in good agreement

Itzhak Tserruya QM05 Budapest 9/8/05 19  Elliptic SPS Weaker increase of v 2 (p T ) at SPS than at RHIC

Itzhak Tserruya QM05 Budapest 9/8/05 20  Elliptic SPS  Hydro with T f =120 MeV reproduce p T spectra but overpredict v 2 SPS data  Predicitions with T f =160 MeV closer to v 2 data but can’t reproduce p T spectra

Itzhak Tserruya QM05 Budapest 9/8/05 21 High p T suppression High p T suppression

Itzhak Tserruya QM05 Budapest 9/8/05 22 π 0 p T spectra at √s NN = 200 GeV AuAu Run2AuAu Run4

Itzhak Tserruya QM05 Budapest 9/8/05 23 Suppression persists all the way till 20 GeV/c Suppression is strong (R AA =0.2!) and flat up to 20 GeV/c Matter is extremely opaque The data should provide a lower bound on the initial gluon density

New SPS data: R CP for h -,  K ±, K 0 s, p,  NA49 R CP (baryon)>R CP (meson)  same systematics as original Cronin data at similar  s  same systematics as RHIC but scaled upward NA57

Itzhak Tserruya QM05 Budapest 9/8/05 25 Theory reproduces ALL quite well SPS data, dNg/dy~ I.Vitev, nucl-th/ Au+Au 200, dNg/dy~1200 I.Vitev, nucl-th/ Cu+Cu 200 X-N Wang PL B595, 165 (2004)

Itzhak Tserruya QM05 Budapest 9/8/05 26 Theory reproduces ALL quite well SPS data, dNg/dy~ I.Vitev, nucl-th/

Itzhak Tserruya QM05 Budapest 9/8/05 27 Theory reproduces ALL quite well Au+Au 200, dNg/dy~1200 I.Vitev, nucl-th/

Itzhak Tserruya QM05 Budapest 9/8/05 28 Theory reproduces ALL quite well Cu+Cu 200 X-N Wang PL B595, 165 (2004)

Itzhak Tserruya QM05 Budapest 9/8/05 29 R AA wrt reaction plane Energy loss depends on the path-length

Itzhak Tserruya QM05 Budapest 9/8/05 30 R AuAu of identified hadrons vs rapidity NO change of R AuAu with rapidity Pions y=0 and y=3.1Protons y=0 and y=3 Au+Au at 200 GeV

Itzhak Tserruya QM05 Budapest 9/8/05 31 Heavy quark Heavy quark (the surprise and the challenge)

Itzhak Tserruya Heavy quark (non-photonic electrons) Suppression is approximately the same as for hadrons. Challenge for energy loss models. PHENIX R AA STAR V 2 Charm quark is suppressed and it flows !!! Strong coupling of charm quark to medium. Contribution from b quark at high p T.

Itzhak Tserruya QM05 Budapest 9/8/05 33 Heavy Flavor: PHENIX  STAR R AA V2V2 They look to me quite consistent V 2 Run4 They look to me quite consistent ?

Itzhak Tserruya QM05 Budapest 9/8/05 34 Heavy Flavor: PHENIX  STAR R AA V2V2 They look to me quite consistent

Itzhak Tserruya QM05 Budapest 9/8/05 35 R AA V2V2 V 2 Run4 They look to me quite consistent ?

Itzhak Tserruya QM05 Budapest 9/8/05 36 Charm production cross section  Factor of two discrepancy in the charm cross sections measured by PHENIX and STAR.  Should be resolved in view of the implications on J/  regeneration.

Itzhak Tserruya QM05 Budapest 9/8/05 37 J/ψ J/ψ

Itzhak Tserruya QM05 Budapest 9/8/05 38 NA50 J/  Reanalysis of data:  Normal nuclear absorption derived from pA data only  = 4.18±0.35 mb  S-U consistent with normal nuclear absorption  Only Pb-Pb shows additional suppression Systematic errors of ~8% not shown

Itzhak Tserruya QM05 Budapest 9/8/05 39 NA50 - NA60 comparison  NA50 and NA60 data consistent with each other.  N part seems to be a good scaling factor to take account of system size.

Itzhak Tserruya QM05 Budapest 9/8/05 40 NA60 J/  comparison to models “None of the models (tuned to reproduce the NA50 data and with specific predictions for In-In) properly describes the observed suppression pattern.” Satz, Digal, Fortunato (percolation) Rapp, Grandchamp, Brown (diss. and recomb.) Capella, Ferreiro (comovers)

Itzhak Tserruya QM05 Budapest 9/8/05 41 J/  at RHIC CuCu  200 GeV/c AuAu  200 GeV/c dAu  200 GeV/c J/   muon arm 1.2 < |y| < 2.2

Itzhak Tserruya QM05 Budapest 9/8/05 42 J/  at RHIC CuCu  200 GeV/c AuAu  200 GeV/c dAu  200 GeV/c AuAu ee 200 GeV/c CuCu ee 200 GeV/c J/   muon arm 1.2 < |y| < 2.2 J/  ee Central arm < y < 0.35

Itzhak Tserruya QM05 Budapest 9/8/05 43 J/  at RHIC CuCu  200 GeV/c AuAu  200 GeV/c dAu  200 GeV/c AuAu ee 200 GeV/c CuCu  62 GeV/c J/   muon arm 1.2 < |y| < 2.2 J/  ee Central arm < y < 0.35 Factor ~3 suppression in central events CuCu ee 200 GeV/c

Itzhak Tserruya QM05 Budapest 9/8/05 44 J/  at RHIC J/   muon arm 1.2 < |y| < 2.2 J/  ee Central arm < y < 0.35 Factor ~3 suppression in central events Data show the same trend within errors for all species and even 62 GeV

Itzhak Tserruya QM05 Budapest 9/8/05 45 R AA vs N part PHENIX and NA50 R AA vs N part : PHENIX and NA50  NA50 data normalized to NA50 p+p point.  Suppression level is similar in the two experiments, although the collision energy is 10 times higher (200GeV in PHENIX wrt 17GeV in NA50)

Itzhak Tserruya QM05 Budapest 9/8/05 46 Comparison to theory (I): normal nuclear absorption Theory Vogt: nucl-th/ Central arm Cold nuclear matter absorption model in agreement with dAu: Tendency to underpredict suppression in most central AuAu and CuCu events Muon arm

Itzhak Tserruya QM05 Budapest 9/8/05 47 Comparison to theory (II) Models that were successful in describing SPS data fail to describe data at RHIC - too much suppression -

Itzhak Tserruya QM05 Budapest 9/8/05 48 Comparison to theory (III) Adding recombination: much better agreement with the data

Itzhak Tserruya QM05 Budapest 9/8/05 49 J/  Rapidity Dependence  No significant change in rapidity shape with centrality.  Same in Cu+Cu  Recombination models expect rapidity shape to become narrower for increasing N part.  Not observed in the data.

Itzhak Tserruya QM05 Budapest 9/8/05 50 R AA vs p T : PHENIX and NA50 J/  suppressed at low-p T. NA50 (“R CP ”)PHENIX

Itzhak Tserruya QM05 Budapest 9/8/05 51 Jets Jets

High p T trigger: punch-through jets 8 < p T (trig) < 15 GeV/c STAR Preliminary p T (assoc)>6 GeV No background subtraction! Clear emergence of the away-side jet For the first time: jet-like peaks seen on near and away side in central Au+Au collisions

Itzhak Tserruya QM05 Budapest 9/8/05 53 Away-side peak: width and yield 8 < p T (trig) < 15 GeV/cp T (assoc)>6 GeV Width unchanged with centrality Away side yield strongly suppressed to the level of R AA 0.15 < p T assoc < 4.0 GeV/c 4.0 < p T trig < 6.0 GeV/c

Itzhak Tserruya QM05 Budapest 9/8/05 54 Intermediate p T trigger: modification of away-side jets hadron-hadron DD Splitting parameter D PHENIX preliminary

Itzhak Tserruya QM05 Budapest 9/8/05 55 Systematics with Centrality  Near side seems to broaden as function of centrality  Splitting parameter D increases with centrality  Similar trend for all systems and energies

Itzhak Tserruya QM05 Budapest 9/8/ Particle Jet Functions PHENIX Preliminary extinguish flow Flow + Jet Jet Only Jet function compatible with expected features of “Mach cone” DATA Simulation

Itzhak Tserruya QM05 Budapest 9/8/05 57 Low-mass pairs Low-mass pairs

Itzhak Tserruya QM05 Budapest 9/8/05 58 CERES low-mass e + e – mass spectrum Almost final results from the 2000 run Pb+Au at 158 GeV per nucleon comparison to the hadron decay cocktail Enhancement over hadron decay cocktail for m ee > 0.2 GeV: 2.43  0.21 (stat) for 0.2 GeV<m ee < 0.6 GeV: 2.8  0.5 (stat) Absolutely normalized spectrum Overall systematic uncertainty of normalization: 21%

Itzhak Tserruya QM05 Budapest 9/8/05 59 NA60 Low-mass dimuons  ,  and even  peaks clearly visible in dimuon channel  Net data sample: events  Mass resolution: 23 MeV at the  position Real data !    Superb data!!!

Clear excess of low mass with centrality 0.2<m  <0.9 GeV/c 2 NA60 data sum of all cocktail sources confirms and consistent with CERES rising with centrality more pronounced at low pT

NA60 low mass: comparison with models Conclusions valid also as a function of p T Predictions for In-In byRapp et al., for = 140 Theoretical yields normalized to data in the mass window m  < 0.9 GeV  Excess shape consistent with broadening of the  (Rapp-Wambach  Mass shift of the  (Brown-Rho) is ruled out  Is this telling us anything about CSR?

Low-mass dileptons in PHENIX All the pairs Combinatorial BG Signal BG determined by event mixing technique, normalized to like sign yield Green band: systematic error w/o error on CB Integral:180,000 above  0 :15,000 PHENIX has mastered the event mixing technique to unprecedented precision (±0.25%). But with a S/B ≥ 100 the statistical significance is largely reduced and the systematic errors are huge

Comparison to cocktail and models Yellow band: total systematic error Horizontal bars =bin width  The statistical significance and the systematic uncertainty expected to be significantly improved with the HBD upgrade.  The HBD is under construction with installation foreseen in 2006 Comparison   K + K - and   e + e -

Itzhak Tserruya QM05 Budapest 9/8/05 64 Open Charm Open Charm

Itzhak Tserruya QM05 Budapest 9/8/05 65 First direct measurement of open charm in Au+Au collisions !! See talk, Zhang(5c) Looking forward to results derived from direct charm meson measurement.

IMR excess at SPS Open charm and Drell-Yan generated with PYTHIA Drell-Yan normalization fixed using the high mass region Open charm normalization using the world-average cc cross section  Clear excess in the IMR (1.2<m < 2.7 GeV/c 2 )  same order of magnitude as the NA50 result  excess is not due to open charm enhancement  the excess is due to a prompt source data prompt charm prompt+charm Excess World-aver. norm. NA60 In+In 158 AGeV

Itzhak Tserruya QM05 Budapest 9/8/05 67 Photons Photons (a hope?)

Itzhak Tserruya QM05 Budapest 9/8/05 68 Direct photons in PHENIX Phys. Rev. Lett. 94, (2005) No significant excess at low p T Expect some improvement in run4 systematic errors.

Itzhak Tserruya QM05 Budapest 9/8/05 69 A new approach in the search for direct photons Any source of real  emits virtual  with very low mass  * direct /  * inclusive 0-20% 60-94%40-60% 20-40% excess of low-mass dileptons (wrt hadronic sources) is assigned to direct photons

Yield of direct photons pQCD x T AB : L.E.Gordon and W. Vogelsang Phys. Rev. D48, 3136 (1993) thermal: D. d’Enterria, D. Perresounko nucl-th/ hydro T 0 =590 MeV  0 =0.15 fm/c Is the excess really due to thermal photons? If yes, are these thermal photons from dense HG or QGP? The rate is above pQCD calculation

Itzhak Tserruya QM05 Budapest 9/8/05 71 Historical regression In 1492 CC started a long journey with three flag ships -la Nina, la Pinta y la Santa Maria - in the quest for the predicted and expected alternative route to India. (in the following CC stands for Cristobal Colon not for a pair of quarks) In 1986 we started a long journey with 2+1+(1) flag ships - AGS, SPS + RHIC + (LHC)- in the quest for the predicted and expected QGP characterized by free quarks and gluons, deconfinement (J/  ) and chiral symmetry restoration (low- mass dileptons). Are we discovering our America? Are we discovering our America? It took quite some time to realize that he had discovered a totally unknown continent (CC actually died in 1506 without knowing it). In 1986 we started a long journey with 2+1+(1) flag ships - AGS, SPS + RHIC + (LHC)- in the quest for the predicted and expected QGP characterized by free quarks and gluons, deconfinement (J/  ?) and chiral symmetry restoration (low- mass dileptons?).

Itzhak Tserruya QM05 Budapest 9/8/05 72 Historical regression (in the following CC stands for Cristobal Colon not for a pair of quarks) Are we discovering our America? Are we discovering our America? In 1986 we started a long journey with 2+1+(1) flag ships - AGS, SPS + RHIC + (LHC)- in the quest for the predicted and expected QGP characterized by free quarks and gluons, deconfinement (J/  ?) and chiral symmetry restoration (low- mass dileptons?).

Itzhak Tserruya QM05 Budapest 9/8/05 73 Summary and Outlook “ that much accomplished, so much left to do” Many thanks to all experiments (BRAHMS, PHOBOS, STAR, NA49, NA50, NA57, NA60) for sharing with me their results prior of the conference. Many thanks also to my colleagues in PHENIX and CERES that provided me copies of their presentations before the conference.