1. Recent Results from.. on Heavy Flavor and Electromagnetic Probes at RHIC Andrew Glenn University of Colorado for the PHENIX collaboration March 27, 2006

2. Andrew Glenn 2Outline Electromagnetic Probes –Direct Photons –Virtual Photons Heavy Flavor Production –Open Charm –Hidden Charm (J/ )

3. March 27, 2006 Andrew Glenn 3 Electromagnetic Probes   space time Hard Scattering Au  Expansion  Hadronization Freeze-out QGP Thermaliztion e- e+ electro-magnetic radiation: , e+e-, m+m- rare, emitted “any time”; reach detector unperturbed by strong final state interaction γ

4. March 27, 2006 Andrew Glenn 4 Photon Sources PRC 69(2004)014903 Initial hard scattering (p+p) pQCD Thermal radiation from QGP (1<p T <3GeV) Hadron-gas interaction (p T <1GeV/c) ()  (), K*  K Compton scattering in hard scattered and thermal partons (Jet-photon conversion) Bremsstrahlung of hard scattered partons in medium (small compared to the above)

5. March 27, 2006 Andrew Glenn 5 NO direct photon suppression (initial state), and large  0 suppression (final state) Direct Photon Baseline S.S.Adler, et. al. (PHENIX Collaboration), PRL 94, 232301(2005) Nuclear Modification factor

6. March 27, 2006 Andrew Glenn 6 Including Virtual Photons phase space factor 1 for high p T g Ratios of M inv bins to lowest one If no direct photons: ratios can be calculated from Dalitz decays If excess: direct photons Ratios

7. March 27, 2006 Andrew Glenn 7 p+p direct photon Thermal Hint? For p T <3GeV/c, thermal photon contribution looks dominant However, recent p+p result needs to be considered –Factor of ~4 larger than NLO pQCD at 3GeV/c! (still within error, though) Smaller errors on real photon will help for making a conclusion. NLO pQCD: L.E.Gordon and W. Vogelsang, PRD48(1993)3136 pQCD is LO!

8. March 27, 2006 Andrew Glenn 8 Measurement of Low Mass Dielectron Continuum in sqrt(s_NN)=200GeV Au-Au Collisions in the PHENIX Experiment at RHIC Alberica Toia Stony Brook University High Mass Virtual Photons Dilepton continuum

9. March 27, 2006 Andrew Glenn 9 Photon Highlights High p T (>6GeV/c ) photon yield is well described by NLO pQCD calculation Virtual photon measurement using very low mass dileptons improves error bars at low p T Hint of non-pQCD (thermal?) photons in central collisions

10. March 27, 2006 Andrew Glenn 10 Heavy Quarks Carry the information of early stage of collisions. –Charm quark is massive (even at RHIC energy). –Creation takes place only at the beginning of collisions. How are heavy quarks are effected by the medium?

11. March 27, 2006 Andrew Glenn 11 Heavy flavor electrons in p+p

12. March 27, 2006 Andrew Glenn 12 Prompt  in p+p PHENIX Preliminary Appears to be little rapidity dependence of heavy quark production in p+p (large errors though) Measurement of Open Heavy Flavor with Single Muons in pp and dAu collisions at 200 GeV Xiaorong Wang, New Mexico State University

13. March 27, 2006 Andrew Glenn 13 Quark Energy Loss   What about heavy quarks ? 2001, proposed “dead cone” effect suggests smaller energy loss of charm Recent theories propose energy loss of charm quark is similar to light quarks. (Armesto et al, PRD 71, 054027, 2005; M. Djordjevic et al., PRL 94, 112301, 2005.)

14. March 27, 2006 Andrew Glenn 14 Heavy Flavor in Au+Au preparing the high p T spectrum (up to p T = 10 GeV/c).

15. March 27, 2006 Andrew Glenn 15 (3) q_hat = 14 GeV 2 /fm (2) q_hat = 4 GeV 2 /fm (1) q_hat = 0 GeV 2 /fm (4) dN g / dy = 1000 Theory curves (1-3) from N. Armesto, et al., PRD 71, 054027 (4) from M. Djordjevic, M. Gyullasy, S.Wicks, PRL 94, 112301 We see strong suppression even for heavy quark (charm). The data provides a strong constraint on the energy loss models. Medium Modification of Heavy Flavor Production Measured by PHENIX in Au+Au Collisions at sqrt(s_NN)=200 GeV Alan Dion State University of New York at Stony Brook Heavy Flavor R AA in Au+Au

16. March 27, 2006 Andrew Glenn 16 Open Charm Flow in Au+Au Theory: Greco, Ko, Rapp: PLB 595 (2004) 202 Significant anisotropy is observed for heavy flavor electron. v2 has good agreement of charm flow assumption below p T < 2.0 GeV/c In high p T region (p T > 2 GeV/c), v2 is reduced. (b quark contribution?) The Azimuthal Anisotropy of Electrons from Heavy Flavor Decays in sqrt{s_{NN}}=200 GeV Au-Au Collisions at PHENIX Shingo Sakai University of Tsukuba Elliptic flow of inclusive single muon in sqrt(s_NN) = 200 GeV Au+Au collision at PHENIX IhnJea Choi Yonsei University

17. March 27, 2006 Andrew Glenn 17 Theory Aside In a calculation by Teaney and Moore (hep-ph/0412346), they calculate the expected elliptic flow (v2) and transverse momentum modifications for different charm quark diffusion coefficients. The two effects go hand in hand. Anything that increases the cross section for interactions will have this general effect.

18. March 27, 2006 Andrew Glenn 18 Open Charm Highlights Binary scaling of total charm yield works well. Nuclear modification factor R AA shows a strong suppression at high p T region. Non zero v2 of heavy flavor electron observed. HEAVY QUARKS ARE SIGNIFICANTLY AFFECTED BY THE MEDIUM

19. March 27, 2006 Andrew Glenn 19 J/ Production QGP Mixed phaseFreeze out Gluon Shadowing (Modification of PDF in nuclei) Nuclear Nuclear absorption by the spectators Cronin effect Color screening (Dissociation by gluons) Need to understand the J/  production in each collision stage. Formation of J/  by cc coalescence Comover scattering

20. March 27, 2006 Andrew Glenn 20 R AA of J/ in Au+Au/Cu+Cu |y|<0.35 1.2<|y|<2.4 Constrained by d+Au Suppression increased toward the central collisions. Factor of 3 suppression at most central (Au+Au) Beyond the suppression from cold matter effect. Same pattern between Au+Au and Cu+Cu at forward-rapidity, but different pattern at mid-rapidity.

21. March 27, 2006 Andrew Glenn 21 R AA and Suppression Models Co-mover (  abs = 1mb) Direct dissociation (+Comover) QGP screening (+Comover, feed down) J/ suppression at RHIC is over-predicted by the suppression models that described SPS data successfully.

22. March 27, 2006 Andrew Glenn 22 Recombination Models Better matching with results compared to the suppression models. Don’t forget about free paramerters. At RHIC (energy): Recombination compensates stronger suppression?

23. March 27, 2006 Andrew Glenn 23 Invariant p T distributions Cu+Cu Extraction of by fitting with A(1+(p T /B) 2 ) -6

24. March 27, 2006 Andrew Glenn 24 as a function of N col as a function of N col Au+Au = RED Cu+Cu = BLUE Dashed: without recombination Solid: includes recombination Recombination model matches better to the data... But don’t forget the error bars nucl-th/0505055

25. March 27, 2006 Andrew Glenn 25 Connected Observables Suppression due to multiple scattering in cold nuclear matter Npart A.M. Glenn, Denes Molnar, J.L. Nagle nucl-th/0602068

26. March 27, 2006 Andrew Glenn 26 Rapidity dependence p+p 40-93% 20-40% 0-20% Cu+Cu (200GeV) p+p 60-94% 40-60% 0-20% 20-40% AuAu CuCu PHENIX Preliminary No significant change in rapidity shape in Au+Au and Cu+Cu. R AA is flat (within errors) as a function of rapidity, which is not predicted by the recombination model. nucl-th/0505055 nucl-th/0507027

27. March 27, 2006 Andrew Glenn 27 R AA vs. p T in Au+Au/Cu+Cu Suppression of J/ yield at low p T in both Au+Au and Cu+Cu. High p T J/ escape the medium? Leakage effect? [Phys. Lett. B 607 (2005)] Might one expect “pile up” at low pT for recombination+energy loss?

28. March 27, 2006 Andrew Glenn 28 J/ Highlights Factor of 3 (4 Cu+Cu) suppression in most central collisions Beyond the suppression from cold matter effects. Over-predicted by the suppression models effective for SPS. Possible signs of recombination, but plenty of open questions (flies in the ointment?) J/Psi measurements in Cu+Cu and Au+Au collisions at sqrt(s) = 200 GeV by PHENIX at RHIC Andry Rakotozafindrabe Laboratoire Leprince Ringuet (LLR) - École Polytechnique (France)

29. March 27, 2006 Andrew Glenn 29 USA Abilene Christian University, Abilene, TX Brookhaven National Laboratory, Upton, NY University of California - Riverside, Riverside, CA University of Colorado, Boulder, CO Columbia University, Nevis Laboratories, Irvington, NY Florida State University, Tallahassee, FL Florida Technical University, Melbourne, FL Georgia State University, Atlanta, GA University of Illinois Urbana Champaign, Urbana-Champaign, IL Iowa State University and Ames Laboratory, Ames, IA Los Alamos National Laboratory, Los Alamos, NM Lawrence Livermore National Laboratory, Livermore, CA University of New Mexico, Albuquerque, NM New Mexico State University, Las Cruces, NM Dept. of Chemistry, Stony Brook Univ., Stony Brook, NY Dept. Phys. and Astronomy, Stony Brook Univ., Stony Brook, NY Oak Ridge National Laboratory, Oak Ridge, TN University of Tennessee, Knoxville, TN Vanderbilt University, Nashville, TN Brazil University of São Paulo, São Paulo China Academia Sinica, Taipei, Taiwan China Institute of Atomic Energy, Beijing Peking University, Beijing France LPC, University de Clermont-Ferrand, Clermont-Ferrand Dapnia, CEA Saclay, Gif-sur-Yvette IPN-Orsay, Universite Paris Sud, CNRS-IN2P3, Orsay LLR, Ecòle Polytechnique, CNRS-IN2P3, Palaiseau SUBATECH, Ecòle des Mines at Nantes, Nantes Germany University of Münster, Münster Hungary Central Research Institute for Physics (KFKI), Budapest Debrecen University, Debrecen Eötvös Loránd University (ELTE), Budapest India Banaras Hindu University, Banaras Bhabha Atomic Research Centre, Bombay Israel Weizmann Institute, Rehovot Japan Center for Nuclear Study, University of Tokyo, Tokyo Hiroshima University, Higashi-Hiroshima KEK, Institute for High Energy Physics, Tsukuba Kyoto University, Kyoto Nagasaki Institute of Applied Science, Nagasaki RIKEN, Institute for Physical and Chemical Research, Wako RIKEN-BNL Research Center, Upton, NY Rikkyo University, Tokyo, Japan Tokyo Institute of Technology, Tokyo University of Tsukuba, Tsukuba Waseda University, Tokyo S. Korea Cyclotron Application Laboratory, KAERI, Seoul Kangnung National University, Kangnung Korea University, Seoul Myong Ji University, Yongin City System Electronics Laboratory, Seoul Nat. University, Seoul Yonsei University, Seoul Russia Institute of High Energy Physics, Protovino Joint Institute for Nuclear Research, Dubna Kurchatov Institute, Moscow PNPI, St. Petersburg Nuclear Physics Institute, St. Petersburg St. Petersburg State Technical University, St. Petersburg Sweden Lund University, Lund 12 Countries; 58 Institutions; 480 Participants* *as of January 2004

30. March 27, 2006 Andrew Glenn 30 BONUS SLIDES

31. March 27, 2006 Andrew Glenn 31 Related talks at SQM Elliptic flow of inclusive single muon in sqrt(s_NN) = 200 GeV Au+Au collision at PHENIX IhnJea Choi Yonsei University Medium Modification of Heavy Flavor Production Measured by PHENIX in Au+Au Collisions at sqrt(s_NN)=200 GeV Alan Dion State University of New York at Stony Brook J/Psi measurements in Cu+Cu and Au+Au collisions at sqrt(s) = 200 GeV by PHENIX at RHIC Andry Rakotozafindrabe Laboratoire Leprince Ringuet (LLR) - École Polytechnique (France) The Azimuthal Anisotropy of Electrons from Heavy Flavor Decays in sqrt{s_{NN}}=200 GeV Au-Au Collisions at PHENIX Shingo Sakai University of Tsukuba Measurement of Low Mass Dielectron Continuum in sqrt(s_NN)=200GeV Au-Au Collisions in the PHENIX Experiment at RHIC Alberica Toia Stony Brook UniversityMeasurement of Open Heavy Flavor with Single Muons in pp and dAu collisions at 200 GeV Xiaorong Wang, New Mexico State University

32. March 27, 2006 Andrew Glenn 32 PHENIX experiment Muon Arms: Muons at forward rapidity J/    1.2<  < 2.4 P  > 2 GeV/c  Central Arms: Hadrons, photons, electrons J/   e+e-  0.35 P e > 0.2 GeV/c  (2 arms x  /2) Centrality measurement: Beam Beam Counters together with Zero degree calorimeters Centrality is mapped to N part (N col ) using Glauber model

33. March 27, 2006 Andrew Glenn 33 Measure inclusive electron pairs or photons Measure  0 and  spectra via 2 decay, and estimate background electron-pairs or photon distribution –Other hadron spectra estimated by m T scaling of power-law fit to  0 –Conservative assumption on normalization: / 0 =0.450.05, / 0 =1.0,  ’ / 0 =1.0 Look for an excess of signals over background Very low-mass dileptons    0-30 90-140 140-200 200-300 R data Kroll-Wada Formula phase space factor is unity for high p T  Compton       Ratios of M inv bins to lowest one (R data ) If no direct photons: the ratios become exactly what can be calculated from Dalitz decay formula above If excess over calculation: direct photons Including Virtual Photons

34. March 27, 2006 Andrew Glenn 34  excess ratio ( measured / background ) –Systematic error revisited and improved: p T -correlated: 7.5%, point-by-point: 7.0% Consistent with Run2 and very low-mass dilepton (~21% relative error to ratio) Note that  * dir /  * incl +1 is slightly different from  meas /  background. Centrality range is different as well. Mass Range:0<M ee <30MeV/c 2 (calculated from that in 90<M ee <300MeV/c 2 )Results

35. March 27, 2006 Andrew Glenn 35 Overlaid with thermal + pQCD calc. Additional ~10 % systematic error from inclusive  included Very low mass dilepton ratio converted to direct photon spectrum –Assumption:  dir /  incl = * dir / * incl (for M ee << M  ) – dir = * dir / * incl   incl  incl is real inclusive photon D. d ’ Enterria, D. Perresounko, nucl- th/0503054 A Thermal Hint?

36. March 27, 2006 Andrew Glenn 36 Direct photon in higher mass Dilepton? Contribution of direct photons converted into electron pairs? Try to see what it looks like –Take the direct photon spectra –Kroll-Wada ’ s formula to convert direct photon to electron-pair spectra –Phase space factor considered (1-m ee 2 /M 2 ) 3 –M = E, |F(m ee )| = 1 –Acceptance filter for PHENIX is not applied Look at higher mass region. Needs a detailed look with taking the acceptance into account. 00  Direct photon internal conversion 0-20% centrality p T >1.0GeV/c Probably not significant compared to predicted thermally radiating dilepton.

37. March 27, 2006 Andrew Glenn 37 Cocktail comparison Data and cocktail absolutely normalized Cocktail from hadronic sources Charm from PYTHIA Predictions are filtered in PHENIX acceptance Good agreement in p 0 Dalitz Continuum: hint for enhancement not significant within systematics What happens to charm? Single e  pt suppression angular correlation??? LARGE SYSTEMATICS!

38. March 27, 2006 Andrew Glenn 38Data/cocktail Measurement [10 -5 counts/event] Predictions [10 -5 counts/event] 0.15-0.7 GeV/c 2 17.8 ± 3.8 ± 1.5012.3 1.1-2.5 GeV/c 2 0.67 ± 0.50 ± 0.111.16

39. March 27, 2006 Andrew Glenn 39 Comparison with theory R.Rapp, Phys.Lett. B 473 (2000) R.Rapp, Phys.Rev.C 63 (2001) R.Rapp, nucl/th/0204003                   

40. March 27, 2006 Andrew Glenn 40 Total Charm Yield in Run2 Au+Au Binary scaling works well for total charm yield dN e /dy is fit to AN coll   = 0.938+/-0.075+/-0.0018 Coming soon: High statistic data in Run4 Au+Au S.S. Adler, et al., PRL 94 082301

41. March 27, 2006 Andrew Glenn 41 Prompt  in Run3 d+Au Suppression(?) in d going direction Enhancement(?) in Au going direction d Au South North Beam direction

42. March 27, 2006 Andrew Glenn 42 Heavy flavor in Run3 d+Au Minimum Bias non-photonic electrons PHENIX preliminary

43. March 27, 2006 Andrew Glenn 43 R AA of heavy flavor electrons Theory curves (1abc) from N. Armesto, et al., PRD 71, 054027 (2ab) from M. Djordjevic, M. Gyullasy, S.Wicks, PRL 94, 112301 PRL accepted recently (nucl-ex/0510047). (1c) q_hat = 14 GeV 2 /fm (1b) q_hat = 4 GeV 2 /fm (1a) q_hat = 0 GeV 2 /fm (2a) dN g / dy = 1000 (2b) dN g / dy = 3500 Clear evidence for strong medium effects!

44. March 27, 2006 Andrew Glenn 44 J/ measurement PHENIX measured the J/ yield in p+p, d+Au, Au+Au and Cu+Cu to understand the J/ production in each stage of collisions. Base line for all measurements  J/   as a function of rapidity, p T Initial stage effect Gluon shadowing Nuclear medium effect Nuclear absorption Cronin effect  J/  as a function of rapidity, p T, X Au p+p collisions d+Au collisions

45. March 27, 2006 Andrew Glenn 45 PHENIX measured the J/ yield in p+p, d+Au, Au+Au and Cu+Cu to understand the J/ production in each stage of collisions. Au+Au collisions Cu+Cu collisions Extract the medium effect Color screening Coalescence  J/  (yield) as a function rapidity, p T collision centrality collision species (Au+Au/Cu+Cu) collision energy (200GeV/62.4GeV) p+p/d+Au collisions Note that feed down effect from  c and  ’ is also important. But they are not accessible with the current RHIC luminosity. J/ measurement

46. March 27, 2006 Andrew Glenn 46 J/ cross section in p+p Cross section vs. rapidity and energy dependence p-p J/Psi – PHENIX 200GeV y Integrated cross section  = 2.61+-0.20(fit)+-0.26(abs)  b Gives a good base line for d+Au, Au+Au and Cu+Cu. nucl-ex/ 0507032 Accepted in PRL

47. March 27, 2006 Andrew Glenn 47 J/ in d+Au Collisions gluons in Pb / gluons in p X Shadowing Eskola, et al., Nucl. Phys. A696 (2001) 729-746. Anti Shadowing XdXd X Au J/  in North y > 0 XdXd X Au J/  in South y < 0 rapidity y South muon arm (y < -1.2) : –large X Au  0.090 Central arm (y  0) : –intermediate X Au  0.020 North muon arm (y > 1.2) : –small X Au  0.003 Understand the cold matter effects –Gluon Shadowing –Cronin effect (p T broadening) –Nuclear Absorption Coverage of X Au in d+Au at PHENIX

48. March 27, 2006 Andrew Glenn 48 J/ in d+Au vs. p T J/ in d+Au vs. p T Cronin effect (p T broadening) Observation of p T broadening at RHIC. Initial state multiple scattering of partons nucl-ex/0507032 accepted in PRL

49. March 27, 2006 Andrew Glenn 49 p T broadening Suppression factor :  vs. p T Comparison to E866 at s = 39 GeV. x Au ~ 0.01 x Au ~ 0.003 x Au ~ 0.1  dAu =  pp (2x197)  Trend of p T broadening at RHIC is consistent with E866 results. nucl-ex/0507032 Accepted in PRL

50. March 27, 2006 Andrew Glenn 50 Nuclear Absorption and Shadowing R dAu vs. rapidity, centrality,  vs. x coverage E866: PRL 84, 3256 (2000) NA3: ZP C20, 101 (1983) (in gold) R dA 0 0.2 0.4 0.6 0.8 1.0 1.2 Rapidity R dAu Weak nuclear absorption :  =1–3 mb (  4.3 mb at SPS) Suppression increased weakly toward the central collisions. Weak shadowing (violation of X Au scaling) :  > 0.92 nucl-ex/0507032 Accepted in PRL

51. March 27, 2006 Andrew Glenn 51 Summary (d+Au J/ measurements) Observation of Cronin effect (p T broadening) Trend of Cronin effect is consistent with lower energy results. Observation of nuclear absorption and shadowing effect. –Nuclear absorption at RHIC is weak (1-3mb) compared to lower energy results (SPS, FNAL) –Shadowing effect is weak A modest baseline measurement for A+A collisions. Further statistics are needed for the detail study of cold matter effects.

52. March 27, 2006 Andrew Glenn 52 Invariant p T distributions J/   e+e- (Au+Au) 20-40% 40-93% p+p 0-20% 20-40% 40-93% J/    +  - (Au+Au) Cu+Cu Extraction of by fitting with A(1+(p T /B) 2 ) -6

53. March 27, 2006 Andrew Glenn 53 Phys. Lett. B 561 (2003) Feed down and J/ suppression Feed down from  c and ’ is important. – 30% from  c and 10% from ’ (FNAL E705, HERA-B) –T diss (’)  T diss () 1.1 T c << T diss (J/) 2 T c (Lattice calc.) –J/suppression at RHIC could be due to the melt of  c and ’? (J/would survive at RHIC.) The melt of  c and  ’ can explain J  suppression at SPS. How about J/  suppression at RHIC? Describe well up to mid-central and more suppression at most central. Feed down is larger at RHIC? Melting of J/  at most central? Need to study  c and  ’ production at RHIC (RHIC-2).