PHENIX Results Y. Akiba (RIKEN Nishina Center) for PHENIX Collaboration RHIC/AGS User’s meeting

The RHIC Physics Program RHIC New State of Partonic Matter Origin of Nucleon Spin

PHENIX Data-Sets Collided 4 different species in 8 years: AuAu, dAu, pp, CuCu 6 energies run: 9.2 GeV, 19 GeV, 22.5 GeV, 62.4 GeV, 130 GeV, 200 GeV 3 times 30 times

PHENIX publications 67 papers published since 2001 –Phys. Rev. Lett.41 –Phys. Rev. C19 –Phys. Rev. D5 –Phys. Letter B2 –Nucl. Phys. A1 (white paper) Total citation: ~5900 – – – – papers published + accepted since January 2007 –PRL9 +1 –PRC7 +2 –PRD2 –PLB1 8 papers in review PHENIX “White Paper” is now a “Renowed” (500+) status, with total of 504 citation.

5 Proton Spin Well measured only ~30% of spin A future challenge Spins + orbital angular momentum need to give the observed spin 1/2 of proton Measuredat RHIC

π 0 A LL : work horse for  G(x) pQCD works for pT>2GeV/c RUN5 resutls: PRD76 (2007)  0 A LL  constraint on  G

RUN6  0 A LL Scaling Errors not included Final RUN6 results will be published soon Gives much stronger constraint on  G

More A LL measurements Many independent probes to understand gluon spin NEW

Forward  0 A N at large x F with MPC 3.0<  <4.0 p  +p  0 +X at  s=62.4 GeV

A N of muons from charm/bottom decays AN of charm decay muons is measured for the first time “Max” value of AN of charm is not well constrained NEW

3D source imaging 3D source imaging reconstructs source parameters reverse engineer the correlation function by an input source function. The analysis suggests that there is a long tail of the source distribution Solutoin of the long-standing “HBD puzzle”? arXiv: , PRL accepted

Scaling of v2 of hadrons More data on v2(pT) of hadrons are accumulated When v2/nq vs KE T /nq (KE T =transverse kinetic enery), all data points are on a universal curve, suggesting that v2 developed in partonic stage PRL98,162301(2007)

Phi meson (small interaction cross section) also follows the number of quark (nq) scaling. More on the scaling of v2: phi flow PRL99, (2007)

v 2 of Direct photon and J/   e + e - First ever at RHIC, v 2 - J/   µ + µ - coming soon J/Psi coalescence ? NEW PHENIX preliminary Direct  v 2 Min Bias Au+Au 200 GeV (Run 4) Sign of direct  v 2 (at high p T ): –Positive == parton emission quenched –Negative == parton emission (Brems.) enhanced

v 4 - scales with v 2 V4V4 p T (GeV/c) V 4 /(n q ) 2 KE T /n q (GeV/c 2 )KE T (GeV/c 2 ) v 2 scales with n q, v 4 with n q 2 partonic degree of freedom V4V4 PHENIX preliminary NEW

π 0 p T spectra at √s NN = 200 GeV RUN2 Au+Au PRL91, RUN4 Au+Au arXiv: [nucl-ex] RAA measurements now extends to 20 GeV/c

Quantitative analysis Comparison with GRV model: dNg/dy=1400arXiv: PRC accepted

R AA beam energy dependence (Cu+Cu)   Cu+Cu 22,62,200 GeV (Run 5) Model calculations indicate quenching expected at  s NN = 22 GeV, but Cronin effect dominates Species dependence to probe space/time of suppression arXiv: 

19 R AA of hadrons and direct photon (AuAu 200GeV) Same suppression pattern for  0 and  : Consistent with parton energy loss and fragmentation in the vacuum R AA for  ‘s larger than  0 R AA for 2 < p T < 5 GeV/c. Why? Ncoll scaling for direct  (except for highest pT point?– Isospin effect?)

More Direct photon R AA Results Central Cu+Cu 200 GeV (Run 5) Direct  R AA vs N part PHENIX Preliminary Min Bias Au+Au 62 GeV (Run 4) Direct photon R AA  1 Is there other evidence for nuclear effects? –Reduced/enhanced radiation due to jet quenching NEW

Modification of jet correlation Two particle of two high pT track (jet correlation) is modified in central Au+Au collisions. Many theory attempts to explain these effect Probing the medium response to fast partons PRL97, (2006) Au+Au

More detailed study of jet correlation D PRL98, (2007)

jet correlations vs reaction plane unchanged near-side peak in the final jet functions when moving away from Reaction plane, indication for away side modification.

 -h Correlations  “measures” recoil parton momentum –Measure fragmentation function D(Z)  -h p+p 200 GeV (Run 5) ~D(z)

J/  suppression in Au+Au High statistics measurement of J/  in AuAu in wide rapidity range –Mid-rapidty J   ee –Forward rapidty J/    Strong suppression of J/  is observed –Consistent with the prediction that J/  s are destroyed in de-confined matter Surprisingly, the suppression is stronger at forward rapidity than in mid-rapidity –J/  formation by recombination of charm pairs in deconfined matter? PRL98, (2007)

R AuAu (run 4) = R AuAu (run 7) Forward rapidity only (for now) More bins at higher centrality Confirm the trend –R AA (y≈1.7) < R AA (y≈0) NEW

J/  d+Au: Cold Nuclear Matter Increased Run 5 p+p statistics (x10 Run 3) as baseline Improved & consistent p+p and dAu analysis –Improved alignment, resolution, yield extraction,… –Cancellation of systematic errors in R dAu Result: CNM = Shadowing(EKS) +  Breakup = 2.8 mb –Consistent within errors with previous results – and with  Breakup =4.2+/-0.5mb (SPS result) PRC77_ (2008) J/  R dAu 200 GeV

J/  R AA Cu+Cu and Au+Au Approx 2x more J/  in Cu+Cu sample than Au+Au sample –More precise N part <100 info Curves show R AA prediction from ad hoc CNM fit to R dAu separately at y=0 and y > 1.2 CNM from R dAu fit describes suppression for N part < 100. J/  R AA 200 GeV arXiv: R dAu constraints are not sufficient to say if suppression beyond cold nuclear matter is stronger at forward rapidity

Heavy flavor electron R AA and flow Two models describes strong suppression and large v 2 Rapp and Van Hee Moore and Teaney From model comparison, viscosity to entropy ratio  /s can be estimated D HQ × 2πT = D HQ ~ 6 x  /(  +p) = 6 x  /Ts   /s ~ (4/3 – 2)/4  The estimate of  /s is close to the conjectured bound 1/4  from AdS/CFT PRL98, (2007) Contraints on  /s

Bottom Measurement Charm and bottom spectra both  x  above FONLL calculations –But ratio is in good agreement with FONLL p+p 200 GeV Charm and bottom extracted via e-h mass analysis NEW

31 total cross section of charm and bottom √s dependence of cross section with NLO pQCD agrees with data total cross section of bottom NEW

Is bottom also suppressed? Does it flow? p+p data indicates that a large contribution of b for pT>2 GeV/c The suppression in high pT is strong and new v2 data suggest significant flow of HF electron in high pT –Is bottom also suppressed? –Does bottom also flows? PRELIMINARY Run-4 Run-7 Rapp & van Hees, PRC 71, (2005) minimum-bias PRL 98, (2007) e ± from heavy flavor NEW

e+e- pairs in p+p Cocktail filtered in PHENIX acceptance Charm, Bottom, DY contributions from PYTHIA Excellent agreement! arXiv:

e+e- pairs in Au+Au Data and Cocktail absolutely normalized –Cocktail normalized to Au+Au measurements Except ccbar Low mass excess –150 < M ee < 750 MeV –X 3.4±0.2(stat.) ±1.3(syst.)±0.7(model) arXiv:

P T Dependence of Au+Au M ee Low Mass excess is a low p T enhancement –Huge excess at lowest p T –Late Phase info 0 < p T < 8 GeV/c0 < p T < 0.7 GeV/c 0.7 < p T < 1.5 GeV/c1.5 < p T < 8 GeV/c PHENIX Preliminary Still significant at high p T  Next topic NEW

Enhancement of almost real photon Kinematic region of e + e - pairs m<300 MeV and 1<p T <5 GeV/c p+p Good agreement of p+p data and hadronic decay cocktail Small excess in p+p at large m ee and high p T Au+Au Clear enhancement visible above for all p T ppAu+Au (MB) 1 < p T < 2 GeV 2 < p T < 3 GeV 3 < p T < 4 GeV 4 < p T < 5 GeV arXiv:

Direct  for p+p, Au+Au New p+p result with  * method agrees with NLO pQCD predictions, and with the measurement by the calorimeter For Au+Au there is a significant low p T excess above p+p expectations Excess is exponential in shape with inverse slope T~ 220MeV Thermal photons from hydrodynamical models with T init =300 – 600MeV at  0 = fm/c are qualitative agreement with the data. NLO pQCD (W. Vogelsang) Fit to pp exp + T AA scaled pp arXiv:

Constrain the properties and evolution of the matter

Summary is very productive for PHENIX Spin physics results –Constraint on gluon polarization from pi0 A LL –More new A LL measurements –A N of forward pi0, heavy flavor decay muons Many heavy ion physics results 3D imagingFlow High p T hadronsJet correlation Direct photonHeavy quark DileptonThermal(?) Photon These results start to give constraint on the properties of the dense matter formed at RHIC