Highlights from PHENIX II: Photons and Leptons Terry Awes, ORNL For the PHENIX collaboration

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:2 Photons and Leptons Penetrating probes that carry information about their production. Rare processes –Need large data samples Large backgrounds –Need precise background determination Background  from decays of   and  Electrons from  conversions Combinatorial Backgrounds Theme: Towards Higher Accuracy

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:3 Improved Statistical errors –Au+Au Statistics: 30 : 10 : 1 ( Runs 7 : 4 : 2 ) Improved Systematic errors –More statistics –Two EMCals More Precise Measurements arXiv:   Au+Au 200 GeV (Run 4)

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:4 Improved p+p Reference Data PHENIX 62 GeV p+p   cross section approx. 2 times higher than ISR average. 200 GeV p+p data 10x (with Run5) J.Phys.G31:S491 (2005)   p+p 62 GeV (Run 6)

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:5 Nuclear Suppression Dependence on:   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: Energy Particle Species   Au+Au 200 GeV (Run 4)    

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:6 Dependence of Nuclear Suppression R AA scales with N part at same  s NN –Some indication for “higher order” effects Approximate scaling with Use R AA (N part,  s NN, Species, Pathlength) to illuminate models Session I: Klaus Reygers PHENIX PRC N Part Pathlength

Direct Photons

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:8 Towards inclusive  (  contribution) Universal   m T -scaling –Independent of centrality in Au+Au Poster: B.Sahlmuller   Au+Au 200 GeV   p+p systematics PRC 75, (2007) PHENIX Preliminary PRC 75, (2007)

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:9 Run 4 (QM06): High p T  suppression –Isospin (PDF) effect (+ ?) PHENIX Preliminary Direct  Au+Au:  Direct =  Inclusive -  Decay Run 2: No  suppression -> Jet quenching (PRL 94, (2005)).

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:10 Direct  R AA Results Central Cu+Cu 200 GeV (Run 5) Direct  R AA vs N part Session VIII: Takao Sakaguchi PHENIX Preliminary Min Bias Au+Au 62 GeV (Run 4) Direct  R AA  1 Is there other evidence for nuclear effects? –Reduced/enhanced radiation due to jet quenching

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:11 Direct  v 2 : Au+Au 200 GeV Interested in sign of direct  v 2 (at high p T ): –Positive == parton emission quenched –Negative == parton emission (Brems.) enhanced Results suggest positive v 2 Session XV: Kentaro Miki Direct  v 2 Min Bias Au+Au 200 GeV (Run 4)

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:12  -h Correlations  “measures” recoil parton momentum –Measure fragmentation function D(Z)  -h p+p 200 GeV (Run 5) ~D(z) Session XV: Matthew Nguyen Poster: A.Hanks Use Near Side peak to determine direct  associated with h, I.e. fragmentation photons

J/  Production

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:14 J/  d+Au: Cold Nuclear Matter Increased Run 5 p+p statistics (x10 Run 3) 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) J/  R dAu 200 GeV Session VI: Matthew Wysocki arXiv:

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:15 J/  Au+Au: CNM Effects Large errors still (need Run 8 d+Au, Run 7 Au+Au) –Comparison suggests more forward suppression beyond CNM than at mid-rapidity –BUT models shown don’t describe R dAu impact parameter dependence J/  R AuAu 200 GeV (Run4) arXiv: |y| < < |y| < 2.2

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:16 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 Session XVIII: Susumu Oda arXiv: R dAu constraints are not sufficient to say if suppression beyond cold nuclear matter is stronger at forward rapidity

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:17 J/  Cu+Cu and Au+Au No (or modest) p T broadening of J/  –Conspiracy of low p T suppression and recombination? Session XVIII: Susumu Oda arXiv:

Low Mass e + e -

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:19 Electron Pair Mass Spectrum p+p Combinatorial Bkground subtraction error 0.25% –Confirmed with special convertor runs Correlated unlike (and like) pairs due to jet and Dalitz photon pair conversions M ee p+p 200 GeV (Run5) Unlike sign Like sign arXiv:

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:20 Hadronic Cocktail to Calculate M ee Based on PHENIX measurements –(Light VM See Session XXIII Y. Nakamiya) Fit to pion spectrum provides excellent fit to all other mesons with M T -scaling assumption –M T -scaling works very well arXiv:

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:21 Measured p+p M ee compared to Cocktail Cocktail filtered in PHENIX acceptance Charm, Bottom, DY contributions from PYTHIA Excellent agreement! arXiv:

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:22 Heavy Quarks in p+p from e + e - c dominant b dominant After subtraction of Cocktail - Fit to a*charm+ b*bottom (with PYTHIA shape) arXiv: Good agreement with single e results Also new analyses via e-h coincidences, single muons, and direct charm measurement –See talks: Session XIV: Yuhei Morino Donny Hornback

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:23 Bottom Measurement Charm and bottom spectra both  x  above FONLL calculations –But ratio is in good agreement with FONLL Session XIV: Yuhei Morino p+p 200 GeV Charm and bottom extracted via e-h mass analysis

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:24 Heavy Flavor via non-photonic Electrons HF strongly suppressed, Significant v 2 –Implies high density, small diffusion coefficient –Estimate  /s = (1.3-2)/4  –Very close to conjectured limit PHENIX : PRL98, (2007) Session XIV: Ralf Averbeck Poster: A.Dion Preliminary Run 7 HF v 2 result:

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:25 Au+Au M ee compared to Cocktail Data and Cocktail absolutely normalized –Cocktail normalized to Au+Au measurements Except ccbar Low mass excess –150 < M ee < 750 –X 3.4±0.2(stat.) ±1.3(syst.)±0.7(model) Intermediate mass agreement arXiv: –Thermal contribution perhaps if ccbar mass spectrum softened by rescatt.

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:26 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 Session XI: Alberica Toia PHENIX Preliminary Still significant at high p T

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:27 High p T Direct  Yield from  * Virtual  with p T >> m ee should be produced directly with a rate and mass distrib. that follows a “Dalitz” form f dir with M Had ->oo Extract Direct  * “excess” as fraction r of f dir needed to describe low mass excess That direct  * fraction of inclusive  * (mostly    and  ) should be the same as the real  fraction of inclusive  (mostly    and  )

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:28 Direct  via  * for p+p, Au+Au New p+p result with  * method agrees with NLO pQCD predictions, and with statistical method at high p T –Confirmation of the method For Au+Au (QM05 result) there is a significant low p T excess above p+p expectations –Interpreted as thermal emission -> Initial T Session XV: Torsten Dahms arXiv:0801.xxxx

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:29 Summary More precise studies of sQGP matter –Systematics of R AA –  -h correlations –Dilepton excess Initial T and evolution –Low p T direct  excess –Heavy Flavor –J/  |y| < 0.35

Terry Awes, ORNL - QM08, Jaipur IndiaSlide:30 PHENIX Data Sets