1 PHENIX Overview PHENIX Overview N. N. Ajitanand Nuclear Chemistry, SUNY, Stony Brook RHIC & AGS Annual Users' Meeting Workshop 2 Bulk and medium properties in heavy ion collisions at RHIC and RHIC-II

N.N. Ajitanand RHIC-AGS PHENIX stands for Pioneering High Energy Nuclear Interaction eXperiment Goals: – Broadest possible study of A+A, p+A, p+p collisions to Study nuclear matter under extreme conditions Using a wide variety of probes sensitive to all timescales Study systematic variations with species and energy –Measure spin structure of the nucleon èThese two programs have produced a detector with unparalleled capabilities What is PHENIX ?

N.N. Ajitanand RHIC-AGS Global Detectors (Luminosity,Trigger) BBC 3.0 < |  | < 3.9 Quartz Cherenkov Radiators ZDC/SMD (Local Polarimeter) Forward Hadron Calorimeter RxNP,HBD Forward Calorimetry 3.1 < |  | < 3.7 MPC PbWO 4 Crystal Forward Muon Arms 1.2 < |  | < 2.4 Central Arm Tracking |  | < 0.35, x F ~ 0 Drift Chamber (DC) momentum measurement Pad Chambers (PC) pattern recognition, 3d space point Time Expansion Chamber (TEC) additional resolution at high pt Central Arm Calorimetry PbGl and PbSc Very Fine Granularity Tower  x  ~ 0.01x0.01 Trigger Central Arm Particle Id RICH electron/hadron separation TOF  /K/p identification PHENIX Detector

N.N. Ajitanand RHIC-AGS –An aerogel and time-of-flight system to provide complete  /K/p separation for momenta up to ~10 GeV/c. –A high resolution Reaction Plane Detector –A vertex detector to detect displaced vertices from the decay of mesons containing charm or bottom quarks. –A hadron-blind detector to detect and track electrons near the vertex. –A muon trigger upgrade to preserve sensitivity at the highest projected RHIC luminosities. –A forward calorimeter to provide photon+jet studies over a wide kinematic range. Upgrades

5 Abilene Christian University, Abilene, Texas, USA Brookhaven National Laboratory (BNL), Chemistry Dept., Upton, NY 11973, USA Brookhaven National Laboratory (BNL), Collider Accelerator Dept., Upton, NY 11973, USA Brookhaven National Laboratory (BNL), Physics Dept., Upton, NY 11973, USA University of California - Riverside (UCR), Riverside, CA 92521, USA University of Colorado, Boulder, CO, USA Columbia University, Nevis Laboratories, Irvington, NY 10533, USA Florida Institute of Technology, Melbourne, FL 32901, USA Florida State University (FSU), Tallahassee, FL 32306, USA Georgia State University (GSU), Atlanta, GA 30303, USA University of Illinois Urbana-Champaign, Urbana-Champaign, IL, USA Iowa State University (ISU) and Ames Laboratory, Ames, IA 50011, USA Los Alamos National Laboratory (LANL), Los Alamos, NM 87545, USA Lawrence Livermore National Laboratory (LLNL), Livermore, CA 94550, USA University of Maryland, College Park, MD 20742, USA Department of Physics, University of Massachusetts, Amherst, MA , USA Old Dominion University, Norfolk, VA 23529, USA University of New Mexico, Albuquerque, New Mexico, USA New Mexico State University, Las Cruces, New Mexico, USA Department of Chemistry, State University of New York at Stony Brook (USB), Stony Brook, NY 11794, USA Department of Physics and Astronomy, State University of New York at Stony Brook (USB), Stony Brook, NY 11794, USA Oak Ridge National Laboratory (ORNL), Oak Ridge, TN 37831, USA University of Tennessee (UT), Knoxville, TN 37996, USA Vanderbilt University, Nashville, TN 37235, USA University of São Paulo, São Paulo, Brazil Academia Sinica, Taipei 11529, China China Institute of Atomic Energy (CIAE), Beijing, P. R. China Peking University, Beijing, P. R. China Charles University, Faculty of Mathematics and Physics, Ke Karlovu 3, Prague, Czech Republic Czech Technical University, Faculty of Nuclear Sciences and Physical Engineering, Brehova 7, Prague, Czech Republic Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, Prague, Czech Republic University of Jyvaskyla, P.O.Box 35, FI Jyvaskyla, Finland Laboratoire de Physique Corpusculaire (LPC), Universite de Clermont-Ferrand, F Aubiere, Clermont-Ferrand, France Dapnia, CEA Saclay, Bat. 703, F Gif-sur-Yvette, France IPN-Orsay, Universite Paris Sud, CNRS-IN2P3, BP1, F Orsay, France Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS-IN2P3, Route de Saclay, F Palaiseau, France SUBATECH, Ecòle des Mines at Nantes, F Nantes, France University of Muenster, Muenster, Germany KFKI Research Institute for Particle and Nuclear Physics at the Hungarian Academy of Sciences (MTA KFKI RMKI), Budapest, Hungary Debrecen University, Debrecen, Hungary Eövös Loránd University (ELTE), Budapest, Hungary Banaras Hindu University, Banaras, India Bhabha Atomic Research Centre (BARC), Bombay, India Weizmann Institute, Rehovot 76100, Israel Center for Nuclear Study (CNS-Tokyo), University of Tokyo, Tanashi, Tokyo 188, Japan Hiroshima University, Higashi-Hiroshima 739, Japan KEK - High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki , Japan Kyoto University, Kyoto, Japan Nagasaki Institute of Applied Science, Nagasaki-shi, Nagasaki, Japan RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama , Japan RIKEN – BNL Research Center, Japan, located at BNL Physics Department, Rikkyo University, Nishi-Ikebukuro, Toshima, Tokyo , Japan Tokyo Institute of Technology, Oh-okayama, Meguro, Tokyo , Japan University of Tsukuba, Tennodai, Tsukuba-shi Ibaraki-ken , Japan Waseda University, Tokyo, Japan Cyclotron Application Laboratory, KAERI, Seoul, South Korea Ewha Womans University, Seoul, Korea Kangnung National University, Kangnung , South Korea Korea University, Seoul , Korea Myong Ji University, Yongin City , Korea System Electronics Laboratory, Seoul National University, Seoul, South Korea Yonsei University, Seoul , Korea IHEP (Protvino), State Research Center of Russian Federation, Protvino , Russia Joint Institute for Nuclear Research (JINR-Dubna), Dubna, Russia Kurchatov Institute, Moscow, Russia PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region , Russia Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Vorob'evy Gory, Moscow , Russia Saint-Petersburg State Polytechnical Univiversity, Politechnicheskayastr, 29, St. Petersburg , Russia Lund University, Lund, Sweden *as of July 2006 and growing 14 Countries; 68 Institutions; 550 Participants* Collaboration, 2006

N.N. Ajitanand RHIC-AGS Recent ( ) Publications Measurement of high-p_T Single Electrons from Heavy-Flavor Decays in p+p Collisions at sqrt(s) = 200 GeV Phys. Rev. Lett.. 97, (2006) Production of omega meson at Large Transverse Momenta in p+p and d+Au Collisions at sqrt(s_NN)=200 GeV Phys. Rev. C 75, (2007) Measurement of Direct Photon Production in p+p collisions at sqrt(s) = 200 GeV Phys. Rev. Lett. 98, (2007) Spectra 10 papers Nuclear Modification of Single Electron Spectra and Implications for Heavy Quark Energy Loss in Au + Au Collisions at sqrt(s_NN) = 200 GeV Phys. Rev. Lett. 96, (2006) Common suppression pattern of high pT eta and pi0 in Au+Au at sqrt(s_NN) = 200 GeV Phys. Rev. Lett. 96, (2006) Centrality Dependence of pi^0 and eta Production at Large Transverse Momentum in sqrt(s_NN) = 200 GeV d+Au Collisions Phys. Rev. Lett. 98, (2007) High transverse momentum eta meson production in p+p, d+Au, and Au+Au collisions at sqrt(s_NN)=200 GeV Phys. Rev. C 75, (2007) cite 71 cite 28 cite 11 cite 1 cite 8 cite 7 cite

N.N. Ajitanand RHIC-AGS Spectra (Contd.) Nuclear Effects on Hadron Production in d+Au and p+p Collisions at sqrt(s_NN)=200 GeV Phys. Rev. C 74, (2006) J/psi Production and Nuclear Effects for d+Au and p+p Collisions at sqrt(s_NN) = 200 GeV Phys. Rev. Lett 96, (2006) Helicity An Update on the Double Helicity Asymmetry in Inclusive Midrapidity $\pi^{0}$ Production for Polarized $p+p$ Collisions at $\sqrt{s}=200$ GeV Phys. Rev. D 73, (R) (2006) Imaging Evidence for a long-range component in the pion emission source in Au+Au Collisions at sqrt(s_NN)=200 GeV Phys. Rev. Lett. 98, (2007) Single Electrons from Heavy-Flavor Decays in p+p Collisions at sqrt(s) = 200 GeV Phys. Rev. Lett. 96, (2006) cite 54 cite 25 cite 8 cite 4 cite

N.N. Ajitanand RHIC-AGS Jet Structure from dihadron correlations in d+Au collisions at sqrt(s_NN)=200 GeV Phys. Rev. C 73, (2006) Modifications to Di-Jet Hadron Pair Correlations in Au+Au Collisions at sqrt(s_NN) = 200 GeV Phys. Rev. Lett. 97, (2006) Jet Properties from Di-Hadron Correlations in p+p Collisions at \sqrt{s} = 200 GeV Phys. Rev. D 74, (2006) Jets 4 papers Azimuthal Angle Correlations for Rapidity Separated Hadron Pairs in d+Au Collisions at sqrt(s_NN) = 200 GeV Phys. Rev. Lett. 96, (2006) Anisotropy 3 papers Scaling properties of azimuthal anisotropy in Au+Au and Cu+Cu collisions at $\sqrt{s_{NN}}=200$ GeV Phys. Rev. Lett. 98, (2007) pi0/photon v_2 in Au+Au collisions at sqrt(s_NN)=200 GeV Phys. Rev. Lett. 96, (2006) Energy Loss and Flow of Heavy Quarks in Au+Au Collisions at sqrt(s_NN) = 200 GeV Phys. Rev. Lett. 98, (2007), cite 115 cite 20 cite 7 cite 24 cite 18 cite

N.N. Ajitanand RHIC-AGS We now look at some schematic perspectives of RHIC Collisions

N.N. Ajitanand RHIC-AGS QCD “Phase Diagram” RHIC collision trajectories start at the low density high temperature region of the phase diagram Questions : What are the phases through which the system evolves and how far is it from the critical point ?

11 Space-time Evolution of Collisions space time Hard Scattering  Expansion  Hadronization Freeze-out jet J/  QGP Thermaliztion  e pK   Au

N.N. Ajitanand RHIC-AGS Lattice QCD prediction: Phase Transition Energy density required for QGP formation Necessary to create ε > 0.6 – 1.0 GeV/fm 3 in heavy ion collisions Necessary to create ε > 0.6 – 1.0 GeV/fm 3 in heavy ion collisions F. Karsch, Prog. Theor. Phys. Suppl. 153, 106 (2004)

N.N. Ajitanand RHIC-AGS PRL87, (2001) Central collisions peripheral collisions time to thermalize the system (  0 ~ fm/c)  Bjorken  ~ GeV/fm 3 ~ 35 – 100 ε 0 Estimate From Measured E T Achieved Energy Density is Well Above the Predicted Value for the Phase Transition Predicted Value for the Phase Transition Achieved Energy Density is Well Above the Predicted Value for the Phase Transition Predicted Value for the Phase Transition 200 GeV Au+Au Collisions studies at RHIC!

N.N. Ajitanand RHIC-AGS Strong quenching observed for high pt hadrons hydro-like flow observed High Energy Density matter produced in 200 GeV Au + Au Initial anisotropy gives large pressure gradients

N.N. Ajitanand RHIC-AGS Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX collaboration Nuclear Physics A Volume 757, Issues 1-2, 8 August 2005, Pages Abstract: Extensive experimental data from high-energy nucleus-nucleus collisions were recorded using the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). The comprehensive set of measurements from the first three years of RHIC operation includes charged particle multiplicities, transverse energy, yield ratios and spectra of identified hadrons in a wide range of transverse momenta (p_T), elliptic flow, two-particle correlations, non- statistical fluctuations, and suppression of particle production at high p_T. Conclusion after first three years of study The results are examined with an emphasis on implications for the formation of a new state of dense matter. We find that the state of matter created at RHIC cannot be described in terms of ordinary color neutral hadrons.

16 Phi meson mT spectra Improved detector systems and high statistics have yielded quality measurements

N.N. Ajitanand RHIC-AGS Direct photons as a function of centrality

N.N. Ajitanand RHIC-AGS In minimum bias collisions the dielectron yield in the mass range between 150 and 750 MeV/c^2 is enhanced by a factor (sta)+- 1.3(syst)+-0.7(model) Dielectrons

N.N. Ajitanand RHIC-AGS

20 Azimuthal Anisotropy in Au+Au Collisions at sqrt(s_NN) = 200 GeV Phys. Rev. Lett. 98, (2007) A universal scaling for the flow of both mesons and baryons is observed for the full transverse kinetic energy range of the data when quark number scaling is employed – strong indication of partonic flow

21 Even the phi which has a very low hadronic scattering cross- nic section develops a v2 which scales with the mesons. The same applies to lambdas and cascades – a strong indication of flow developing at the partonic stage. v_2 values for (d^bar)d suggest that elliptic flow is additive for composite particles. Phi meson Flow nucl-ex/

N.N. Ajitanand RHIC-AGS Such a low value is consistent with the observation of substantial elliptic flow and may provide the conditions for a special medium response to hard probes such as Mach flow R. Lacey et al. Phys. Rev. Lett. 98, (2007) The shear viscosity to entropy ratio ( eta /s) is estimated for the hot and dense QCD matter created in 200 GeV Au+Au collisions at RHIC. A very low value is found; eta /s~0.1, which is close to the conjectured lower bound (1/4 pi ) Shear viscosity to Entropy ratio

N.N. Ajitanand RHIC-AGS G. D. Moore, D. Teaney hep-ph/ Calculation of the charm spectrum and the elliptic flow as a function of the diffusion coefficient implies surprisingly strong rescattering behaviour for the heavy quark. An indication of the rather special attributes of the matter formed Charm Diffusion

24 Energy Loss and Flow of Heavy Quarks Phys. Rev. Lett. 98, (2007) A comparison to transport models which simultaneously describe RAA(pT) and v2(pT) suggests that the viscosity to entropy density ratio is close to the conjectured quantum lower bound, i.e., near a perfect fluid.

N.N. Ajitanand RHIC-AGS Although a part of this effect may be trivially related to the contribution of resonances, the possibility of medium modification contributions is an interesting area of investigation. One way to do this would be to look at the source function at different orientations with respect to the reaction plane Imaging Studies Source functions extracted for charged pions produced in Au+Au collisions show non-Gaussian tails. Phys. Rev. Lett. 98, (2007)

26 Inclusive charged hadron multiplicity fluctuations PHENIX Preliminary Exhibit a universal power law scaling as a function of Npart. Further studies of this type are required for investigating the neighborhood of the critical point.

N.N. Ajitanand RHIC-AGS There is strong evidence to support the view that the medium thermalizes rapidly during the partonic stage and exhibits a high degree of collectivity. One now needs to study the medium further in terms of its response to various probes

28 Jets are a natural probe of the Medium In relatvistic heavy ion collisions hard parton- parton processes occur early Scattered partons propagate through the medium radiating gluons and interacting with partons of the medium Finally partons fragment, (possibly) outside the medium

29 Armesto,Salgado,Wiedemann hep-ph/ Possible Modifications of Jet Topology Mach Cone,Wake Effect or “sonic boom” Stoecker nucl-th/ Muller,Ruppert Hep-ph/ Casalderrey-Solana, Shuryak, Teaney, arXiv hep ph/ (2004) Flow induced Deflection Cherenkov Cone Strong pT dependence Cherenkov Cone Strong pT dependence A. Majumdar Hard Probes 2006

30 J. Friess, S. Gubser, G. Michalogiorgakis, S. Pufu hep-th/ Graviton perturbations of AdS_5- Schwarzschild generated by a string trailing behind an external quark moving with constant velocity Components of the stress tensor exhibit directional structures in Fourier space at both large and small momentum. Green lines are experimental peaks of away side jet structure seen by PHENIX ADS-CFT approach

31 Jet Study via Assorted Correlations Associated low pT particle pT High pT Hadron Correlation Function N(pT)

32 It is necessary to decompose the correlation function to obtain the Jet Function! Two source model gives : Correlation Flow Jet Sets a0 Condition Zero Yield At Minimum (ZYAM) nucl-ex/ Ajitanand et. al. Normal Jet Shapeabnormal Jet Shape Simulation Test of Jet Recovery Di-jet faithfully recovered. Method has become the standard method of jet analysis

GeV Au+Au : Hadron Jet Shapes Jet-pair distributions resulting from decomposition show significant away side modification. Deflection or medium response ? Jet-pair distributions resulting from decomposition show significant away side modification. Deflection or medium response ? PRL 97, (2006) 200 GeV Au+Au 1<pT<2.5 vs 2.5<pT<4.0

34 System Size and Energy Dependence of Jet-Induced Hadron Pair Correlation Shapes The broadening and peak location are found to depend upon the number of participants in the collision, but not on the collision energy or beam nuclei. These results are consistent with sound or shock wave models, but pose challenges to Cherenkov gluon radiation models nucl-ex/ D,rms are shape parameters for double Gaussian fit to jet correlation

35 Dip to Shoulder ratio vs pT for different trigger pT ranges Behaviour for Au+Au is quite different from p+p, indicative of “shoulder” region containing medium response to energetic jets Disentangling “Mach Cone ” (Shoulder) and normal jet (dip) regions Dip Shoulder

36 Associated mesons and baryons are similarly modified as would be expected If in-medium modification is the cause of the away side bending PHENIX Preliminary Meson vs. Baryon associated partner (for fixed Hadron trigger)

37 Phys. Rev. C 69, (2004) In central collisions at intermediate transverse momenta ~ GeV/c, proton and anti-proton yields constitute a significant fraction of the charged hadron production and show a scaling behavior different from that of pions. This can be explained on the basis of parton coalescence and fragmentation. Rcp of Identified Charged Particle Spectra in Au+Au Collisions at sqrt(s_NN) = 200 GeV

38 The conditional yield of mesons triggered by baryons (and anti-baryons) and mesons in the same pT range rises with increasing centrality. These data are consistent with a picture in which hard scattered partons produce correlated p and p^bar in the p_T region of the baryon excess Effects of parton coalescence on jet yields Phys. Lett. B 649 (2007) ,

N.N. Ajitanand RHIC-AGS Probing medium modification via 3-particle correlations

40 along azimuth Polar plot 3 Particle Correlations in High pT Framework (*) Normal Jet Same Side Away Side Assoc. pTs (2,3) *  12 *  = along radius *  12 *  13 *  _ = Hi pT(1)

41 Deflected jet sim Data shows strong away side modification Mach Cone sim High pT(1) Normal jet sim Same Side Away Side High pT(1) 3Particle Correlations in High pT Framework

42 Simulated Deflected jet Simulated Mach Cone The data validates the presence of a Mach Cone but does not rule out contributions from other topologies. Azimuthal variation along ridge Data

43 Looking ahead to the LHC Phi Eta Et Phi Et Eta Jet+Flow Jets Remove Flow & soft background A Simulated Event

44 Expected landscape for Mach flow signal Once leading jet candidates have been identified the three-particle correlation method can be applied to look for medium modification in the event !

45 Tsunami : Nature’s awesome medium response to a hard event !!

46 Future Investigations Energy scan of fluctuations for critical point determination Reaction Plane associated studies – energy loss, charge asymmetry,jet properties, imaging … v2 fluctuations : seperating partonic and hadronic contributions Detailed study of medium response Detailed study of deconfinement signals Conclusions Global properties such as flow arise early during the partonic stage QGP medium formed exhibits properties of a near-perfect, near-zero viscosity fluid Indications of medium excitation e.g. Mach cone formation System probably evolves through a second order phase transition with some evidence to indicate trajectory is not far from the critical point

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