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News from PHENIX on extremely dense and hot matter

News from PHENIX on extremely dense and hot matter

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News from PHENIX on extremely dense and hot matter

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

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

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

  4. 4 Correlated particle yield (forward) 2008 data Trigger π0 or h± Associate π0:3.1<η<3.9 pT = 0.45-1.59 GeV π0 d Au Y<0 Y>0 IdAu Pairs are suppressed vs. p+p Larger suppression for more central d+Au collisions Ncoll Mike Leitch - PHENIX QM09

  5. 5 Correlation width Trigger π0 or h± π0 dAu 0-20% d Au dAu 40-88% Y<0 Y>0 pp Preliminary data say - No significant signal for: large broadening centrality dependence for mid-rapidity π0 Mike Leitch - PHENIX QM09

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

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

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

  9. Theory prediction of dilepton emission 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+gq+e+e- not included Vacuum EM correlator Hadronic Many Body theory Dropping Mass Scenario q+q annihilation (HTL improved) (q+gq+gqee not shown) Yasuyuki Akiba - PHENIX QM09

  10. Virtual photon emission rate at y=0, pt=1.025 GeV/c 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+g* is not shown; it is similar size as HMBT at this pT Vaccuum EM correlator Hadronic Many Body theory Dropping Mass Scenario q+q annihilaiton (HTL improved) (q+gq+gqee not shown) Yasuyuki Akiba - PHENIX QM09

  11. Excess of virtual photon Excess of electron pairs over the cocktail ~ constant with mass at high pT. Excess converted to virtual photon yield via divided by 1/M shape from the virtual photon decay. The distribution is ~flat over half GeV/c2 Extrapolation to M=0 should give the real photon emission rate. No indication of strong modification of EM correlator at high pT ! presumably the virtual photon emission is dominated by processes e.g. p+rp+g* or q+gq+g* Excess*M (A.U). Yasuyuki Akiba - PHENIX QM09

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

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

  14. J/ in Au+Au Suppression at RHIC ~ at SPS! What is pT dependence? Simple color screening: low pT J/ lost, higher pT 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 Upsilon in p+p Cross section follows world trend Mike Leitch - PHENIX QM09

  16. 16 Upsilon suppressed in Au+Au! Au+Au RAA [8.5,11.5] < 0.64 at 90% C.L. Mike Leitch - PHENIX QM09

  17. 17 Should ’s be suppressed?  as onium melting baseline… • abs of  ~1/2 of J/Ψ : E772 (PRL 64, 2479 (1990)) • E772  nuclear dependence corresponds to RAuAu = 0.81 • Lattice expectations in Au+Au - 2S+3S suppressed: RAuAu = 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 (pT>8 GeV/c) & ~25%? at our pT • PRL84 (2000) 2094 Mike Leitch - PHENIX QM09

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

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

  20. arXiv:0903.4886 (Run-4 data) High-pT v2 Carla Vale - PHENIX QM09

  21. in-plane intermediate out-of-plane Out-of-plane vs. in-plane pT Run-7 RAA NPart • Out-of plane RAA nearly flat with centrality at low pT • In- and out-of-plane converge at high-pT (~10GeV/c) Carla Vale - PHENIX QM09

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

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

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

  25. Upgrades* increase direct jet tags, heavy quarks PHENIX Upgrades Forward Calorimeter  at = 1-3 Taggedg-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. More fun awaits! Need your help if we are to get… Conclusion: Happy Birthday Larry! Happy Birthday Jean-Paul!

  27. backup slides

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

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

  30. v2 Comparisons to Geometric Models • E.Shuryak: PRC 66 027902 (2002) • Geometric limit: v2(high pT) < v2max(b) • Too large for a pure “jet quenching” • A.Drees, H.D.Feng, J.Jia: Phys.Rev.C71:034909,2005 • Jet absorption proportional to matter density; • Can’t reproduce the large v2. • V. Pantuev: arXiv:hep-ph/0506095 • Corona effect, L ~ 2fm; • J.Liao and E.Shuryak: arXiv:0810.4116 • Stronger jet quenching at near-Tc region; Rui Wei - PHENIX QM09

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

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

  33. 33/12 Nuclear Effects Should modify low pT direct g 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 g yield by nuclear effects? • Run 8 analysis underway: x30 statistics 04/02/2009 Quark Matter '09 Y. Yamaguchi

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

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

  36. Both ridge & shoulder yields grow

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

  38. From the bulk or jet-like? arXiv:0712.3033 pT spectra Particle content PHENIX PRL 101, 082301 (2008) arXiv:0712.3033 Answer: it’s more like the bulk! QGP-like

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

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

  41. In the most central collisions

  42. Jet reconstruction in Au+Au Seeded cone and kT algorithms; Correct for underlying event

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

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

  45. v2 pT (GeV/c) Quantifying the viscosity Need: • 3-d viscous hydro calculations • Precision data • Mass dependence of v2 + other observables for pT transport Romatschke & Romatschke, arXiv:0706.1522 PHENIX Preliminary /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

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

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

  48. High pT 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 < ωc < 25GeV (from quarks)

  49. Virtual Photon Measurement • Any source of real g can emit g* with very low mass. • Relation between the g* yield and real photon yield is known. Eq. (1) S : Process dependent factor • Case of Hadrons • Obviously S = 0 at Mee > Mhadron • Case of direct g* • If pT2>>Mee2 • Possible to separate hadron decay components from real signal in the proper mass window.