1. News from PHENIX on extremely dense and hot matter B. Jacak Stony Brook April 24, 2009

2. 2 Some (selected) news from PHENIX l Initial state (in honor of Larry) Parton structure of nucleus Initial temperature achieved l Di-lepton emission l Interactions within the plasma (in honor of Jean-Paul) Color screening: J/ ,  (!) Opacity & energy loss New data to constrain the imagination of our creative friends

3. 3 3 @forward rapidity with mid-rapidity hadron trigger Color Glass Condensate suppression of pairs broadening of correlation Kharzeev, NPA 748, 727 (2005) P T is balanced by many gluons Dilute parton system (deuteron) Dense gluon field (Au) shadowing (non-LT) suppression of pairs vs. singles Vitev, hep-ph/0405068v2 Suppression of hadron pairs in d+Au Sharing of gluons by near neighbor nucleons

4. 4 Mike Leitch - PHENIX QM09 4 Pairs are suppressed vs. p+p Larger suppression for more central d+Au collisions Correlated particle yield (forward) π0π0 Trigger π 0 or h ± Aud Y<0Y>0 N coll I dAu Associate π 0 : 3.1< η <3.9 p T = 0.45-1.59 GeV 2008 data

5. 5 Mike Leitch - PHENIX QM09 5 Preliminary data say - No significant signal for: large broadening centrality dependence for mid-rapidity π 0 pp dAu 0-20% dAu 40-88% π0π0 Trigger π 0 or h ± Aud Y<0Y>0 Correlation width

6. 6 6 Exponential fit of p T : T avg = 221 ±23 ±18 MeV Multiple hydro models reproduce data T init ≥ 300 MeV arXiv:0804.4168v1 [nucl-ex] Initial State Temperature: direct photons Low mass, high p T e + e-  nearly real photons Large enhancement above p+p in the thermal region

7. 7 Lepton pair emission  EM correlator Emission rate of dilepton per volume Boltzmann factor temperature EM correlator Medium property   ee decay Hadronic contribution Vector Meson Dominance qq annihilation Medium modification of meson Chiral restoration From emission rate of dilepton, the medium effect on the EM correlator as well as temperature of the medium can be decoded. e.g. Rapp, Wambach Adv.Nucl.Phys 25 (2000) q q Thermal radiation from partonic phase (QGP) Yasuyuki Akiba - PHENIX QM09

8. 8 Relation of dileptons and virtual photons Emission rate of dilepton per volume Emission rate of (virtual) photon per volume Relation between them Virtual photon emission rate can be determined from dilepton emission rate For M  0, n  *  n  (real) so real photon emission rate can also be determined M x dNee/dM gives Virtual photon yield Dilepton virtual photon Prob.  *  l + l - This relation holds for the yield after space-time integral Yasuyuki Akiba - PHENIX QM09

9. 9 Theory prediction of dilepton emission Vacuum EM correlator Hadronic Many Body theory Dropping Mass Scenario q+q annihilation (HTL improved) (q+g  q+   qee not shown) Theory calculation by Ralf Rapp at y=0, pt=1.025 GeV/c Usually the dilepton emission is measured and compared as dN/dptdM The mass spectrum at low pT is distorted by the virtual photon  ee decay factor 1/M, which causes a steep rise near M=0 qq annihilation contribution is negligible in the low mass region due to the m**2 factor of the EM correlator In the calculation, partonic photon emission process q+g  q+   q+e + e - not included Yasuyuki Akiba - PHENIX QM09

10. 10 Virtual photon emission rate at y=0, pt=1.025 GeV/c Vaccuum EM correlator Hadronic Many Body theory Dropping Mass Scenario q+q annihilaiton (HTL improved) (q+g  q+   qee not shown) The same calculation, but shown as the virtual photon emission rate. The steep raise at M=0 is gone, and the virtual photon emission rate is more directly related to the underlying EM correlator. When extrapolated to M=0, the real photon emission rate is determined. q+g  q+  * is not shown; it is similar size as HMBT at this pT Yasuyuki Akiba - PHENIX QM09

11. 11 Excess of virtual photon Excess of electron pairs over the cocktail ~ constant with mass at high p T. Excess converted to virtual photon yield via divided by 1/M shape from the virtual photon decay. The distribution is ~flat over half GeV/c 2 Extrapolation to M=0 should give the real photon emission rate. No indication of strong modification of EM correlator at high p T ! presumably the virtual photon emission is dominated by processes e.g.  +    +  * or q+g  q+  * Excess*M (A.U). Yasuyuki Akiba - PHENIX QM09

12. 12 Large low mass dilepton excess at low p T 0 < p T < 8 GeV/c 0 < p T < 0.7 GeV/c 0.7 < p T < 1.5 GeV/c 1.5 < p T < 8 GeV/c Low p T shape of the excess seems incompatible with a constant virtual photon emission rate… Large enhancement of EM correlator at low mass, low p T ? Yasuyuki Akiba - PHENIX QM09

13. 13 Quarkonia (cc, bb bound states) l Important production channel: g+g fusion Sensitive probe of gluon density, distribution + plasma l Lovely idea: Probe plasma (color) screening length using different radius bound states l Alas, Mother Nature can be nasty! They decay into each other, making spectroscopy more complicated

14. 14 J/  in Au+Au Suppression at RHIC ~ at SPS! What is p T dependence? Simple color screening: low p T J/  lost, higher p T not Helmut Satz & friends <1990 AdS/CFT (“hot wind” break up): Liu, Rajagopal,Wiedemann PRL 98, 182301(2007) Regeneration (2-component): Zhao, Rapp hep-ph/07122407 & private communication Equilibrating Parton Plasma: Xu, Kharzeev, Satz, Wang, hep-ph/9511331 Gluonic dissoc. & flow: Patra, Menon, nucl-th/0503034 Mike Leitch - PHENIX QM09

15. 15 Mike Leitch - PHENIX QM09 15 Upsilon in p+p Cross section follows world trend

16. 16 Au+Au R AA [8.5,11.5] < 0.64 at 90% C.L. Mike Leitch - PHENIX QM09 16 p+pAu+Au N[8.5,11.5]10.5 (+3.7/-3.6) 11.7 (+4.7/-4.6) N J/Ψ 2653 ±70±345 4166 ±442(+187/-304) R AA (J/Ψ)---0.425 ±0.025±0.072 Upsilon suppressed in Au+Au!

17. 17 Mike Leitch - PHENIX QM09 17 R AuAu (y=0) J/Ψ0.425 ± 0.025 ± 0.072 8.5<M<11.5 GeV< 0.64 at 90% C.L.  abs of  ~1/2 of J/ Ψ : E772 (PRL 64, 2479 (1990)) E772  nuclear dependence corresponds to R AuAu = 0.81 Lattice expectations in Au+Au -  2S+3S suppressed: R AuAu = 0.73 absorption x lattice ~ 0.73 x 0.81 ~ 0.60 ??? need serious theory estimate instead of this naïve speculation! e.g. Grandchamp et al. hep-ph/0507314 ALSO:  in anti-shadowing region CDF: 50% of  from  b (p T >8 GeV/c) & ~25%? at our p T PRL84 (2000) 2094  as onium melting baseline… Should  ’s be suppressed?

18. 18 Quarkonium spectroscopy l This long awaited era has arrived l RHIC Run-10 in 2010  increased statistical reach l The devil is in the details! As usual… Getting it all right is a challenge/opportunity for theory! l The data will constrain correlations among heavy quarks in the strongly coupled (strong correlated!) matter at T = 2-3 T c

19. 19 Interactions within the plasma l Experimentalist’s simple minded picture Strong coupling = interactions among multiple neighbors l Of course this causes correlations within plasma also increases opacity so, is the quark gluon plasma “black”?

20. 20 High-p T v 2 arXiv:0903.4886 (Run-4 data) Carla Vale - PHENIX QM09

21. 21 pTpT N Part R AA Out-of plane R AA nearly flat with centrality at low p T In- and out-of-plane converge at high-p T (~10GeV/c) Out-of-plane vs. in-plane in-plane intermediat e out-of- plane Carla Vale - PHENIX QM09 Run-7

22. 22 Away-side yield RP dependence at high-p T in-plane out-plane Away PTY 0 π φsφs π π PTY = per-trigger yield Penetrating production in-plane out-plane π π Away PTY 0π φsφs Tangential production Carla Vale - PHENIX QM09

23. 23 Away side yield Away side yields drop from in-plane to out-of- plane: favor penetrating production picture Carla Vale - PHENIX QM09 Medium is gray, not black!

24. 24 The way forward p+p slope: 6.89  0.64 Au+Au slope: 9.49  1.37 fragmentation of  tagged jets in/out of medium Challenge: understand energy transfer to/from the medium! Coupling properties…

25. 25 Upgrades* increase direct  jet tags, heavy quarks PHENIX Upgrades Forward Calorimeter   at  = 1-3 Tagged  -jet correlations Increased acceptance Silicon VTX, FVTX Tag displaced vertex for heavy quark decays Track charged hadrons *In addition to RHIC-II luminosity upgrade x8

26. 26 Conclusion: Happy Birthday Larry! Happy Birthday Jean-Paul! More fun awaits! Need your help if we are to get…

27. 27 l backup slides

28. 28 Local Slopes of Inclusive m T Spectra l Data have soft m T component not expected from hadron decays l Note: Local slope of all sources! need more detailed analysis Axel Drees 28 Soft component below m T ~ 500 MeV: T eff < 120MeV independent of mass more than 50% of yield T data ~ 120 MeV T data ~ 240 MeV

29. 29 J/  in p+p and d+Au EKS; σ CNM = 0,1,2,3,4,…15 mb

30. 30 v 2 Comparisons to Geometric Models l V. Pantuev: arXiv:hep-ph/0506095 Corona effect, L ~ 2fm; l J.Liao and E.Shuryak: arXiv:0810.4116 Stronger jet quenching at near-T c region; l E.Shuryak: PRC 66 027902 (2002) Geometric limit: v 2 (high p T ) < v 2 max (b) Too large for a pure “ jet quenching ” l A.Drees, H.D.Feng, J.Jia: Phys.Rev.C71:034909,2005 Jet absorption proportional to matter density; Can ’ t reproduce the large v 2. Rui Wei - PHENIX QM09

31. 31 Mike Leitch - PHENIX QM09 31  determined three different ways: single electron spectra methods: cocktail subtraction converter di-electrons Muon measurement at forward rapidity is consistent d  heavy /dy (mb) Open Heavy Flavor

32. 32 b quarks and medium effects… B meson spectra e-h correlations to tag D vs. B decays b + c ! Oh oh!

33. 33 04/02/2009Quark Matter '09 Y. Yamaguchi Should modify low p T direct  yield → Evaluate using d+Au data.  Systematic errors on Run3 d+Au results are still large.  At 2-3 GeV/c, data looks in agreement with pQCD calculation. → No modification of direct  yield by nuclear effects?  Run 8 analysis underway: x30 statistics 33/12 Nuclear Effects

34. 34 Calculations by S.Bass et al in arXiv:0808.0908 Comparing to energy loss models II Carla Vale - PHENIX QM09

35. 35 Do both jets shock the medium? p+p central Au+Au 3<p t,trigger <4 GeV p t,assoc. >2 GeV Au+Au 0-10% preliminary STAR

36. 36 Both ridge & shoulder yields grow

37. 37 Away/near to ~ cancel acceptance Shoulder and ridge have the same physics! See also Rudy Hwa, Jiangyong Jia recent talks

38. 38 From the bulk or jet-like? arXiv:0712.3033 Answer: it’s more like the bulk!  QGP-like PHENIX PRL 101, 082301 (2008) p T spectra Particle content

39. 39 “probe” particles: q or g, resulting in hadron jet l p T < 1.5 GeV/c “thermal” particles radiated from bulk of the medium l p T > 3 GeV/c jets (hard scattered q or g) heavy quarks, direct photons describe by perturbative QCD produced early→“external” probe q q leading particle

40. 40 (shear generally a phenomenon in crystals but not liquids) Are shocks in strongly coupled EM plasma. So sQGP could also support shockwaves

41. 41

42. 42 In the most central collisions

43. 43 Jet reconstruction in Au+Au Seeded cone and k T algorithms; Correct for underlying event

44. 44 Radiated photons  T init exp + N coll scaled pp Fit to pp NLO pQCD (W. Vogelsang) In p+p: pQCD works to low p T In Au+Au: soft (thermal) excess fit with exponential T = 221 ± 23 ± 18 MeV (central) T = 224 ± 16 ± 19 MeV (MB) arXiv: 0804.4168

45. 45 T init > T c ! To unfold hydro evolution: Compare to photon spectrum from hydro models T decreasing with time T init ~ 300-600 MeV T c ~ 170 MeV D’Enterria & Peressounko, EPJ C46 (2006) 451 T init (MeV) time    (fm/c) G. David

46. 46 Quantifying the viscosity Need: 3-d viscous hydro calculations Precision data Mass dependence of v 2 + other observables for p T transport p T (GeV/c) v2v2  /s ~ 0 - 0.8 Recall: in ideal hydro mfp =0 Conjectured  /s bound: 1/4  Work is underway to control: initial state geometry gluon distribution Romatschke & Romatschke, arXiv:0706.1522 PHENIX Preliminary

47. 47 p+pAu+Au (MB) Gluon Compton q  g q e+e+ e-e- Dileptons at low mass and high p T m<2  only Dalitz contributions p+p: no enhancement Au+Au: large enhancement at low p T A real  source  virtual  with v. low mass We assume internal conversion of direct photon  extract the fraction of direct photon PHENIX Preliminary 1 < p T < 2 GeV 2 < p T < 3 GeV 3 < p T < 4 GeV 4 < p T < 5 GeV r : direct  * /inclusive  * Direct  * /Inclusive  * determined by fitting each p T bin

48. 48 direct photons via e+e- for low mass, p T > 1 GeV/c direct  * fraction of inclusive  * (mostly  ,  ) is  real  fraction of  (mostly  ,  ) low mass and p T >> m ee dominated by decay of  * m ee hadron cocktail

49. 49 High p T photons in heavy ion collisions Should be the reference, but they are modified: Isospin effect (n≠p) + cold nuclear effect (EMC from EKS) + eloss 20 < ω c < 25GeV (from quarks)

50. 50 Virtual Photon Measurement  Case of Hadrons Obviously S = 0 at M ee > M hadron  Case of direct  * – If p T 2 >>M ee 2  Possible to separate hadron decay components from real signal in the proper mass window.  Any source of real  can emit  * with very low mass.  Relation between the  * yield and real photon yield is known. S : Process dependent factor Eq. (1)

51. 51 Where does the lost energy go? l Radiated particles still correlated with the jet l Completely absorbed by plasma Thermalized? Collective conservation of momentum? l Excites collective response in plasma Shocks or sound waves? Wakes in the plasma?