Multiparticle Angular Correlation Measurements: A Powerful Probe for the s. QGP at RHIC 22 nd Winter Workshop on Nuclear Dynamics La Jolla – California March. 12 – 18 2006 Wolf G Holzmann for the PHENIX Collaboration
Strongly interacting, high energy density matter created at RHIC! Pressure Flow Extrapolation From ET Distributions time to thermalize the system (t 0 ~ 0. 2 - 1 fm/c) e. Bjorken ~ 5 - 15 Ge. V/fm 3 ~ 35 – 100 ε 0 Phase Transition: The Energy Density is Well Above the Predicted Value for the Phase Transition ! M. Issah, this session The matter is strongly interacting with quark degrees of freedom !
Tomographic Probe of the medium: Jets PHENIX Preliminary 3. 0<p. T<6. 0 p+p Jets are Remarkable Probes for this High-density Matter • Auto-Generated on the right time-scale • Calibrated • Calculable (p. QCD) • Accessible statistically via correlations in Au+Au
Reminder: (Di)Jet correlations strongly modified in Au+Au T. Renk, J. Ruppert hep-ph/0509036 Away-side peak consistent with mach-cone scenario nucl-ex/0507004 Strong centrality dependent modification of away-side jet in Au+Au What are the next steps? nucl-th/0406018 Stoecker hep-ph/0411315 Casalderrey-Solana, et al Not the only explanation: Cherenkov gluon radiation: nucl-th/0507063 Koch, Majumder, X. -N. Wang Jets and Flow couple: hep-ph/0411341 Armesto, Salgado, Wiedemann
The next steps: Issues: mechanistic details of quenching Ø new and reliable jet extraction methodologies Ø particle species dependence of jet modification Ø system size dependence of jet modification Ø mach cones or what: novel three particle correlation approach
Decomposition of flow and jet signals Subtraction Phys. Rev. C 72, 011902 (2005) Two source model : Flow (H) & Jet (J) a 0 is obtained without putting any constraint on the Jet shape by requiring Extinction High pt particle constrained perpendicular to RP Unconstrained 1 (A) LP harmonic Constrained 2 (B) i. e. Zero Yield At Minimum (ZYAM) Constraint byte Reliable decomposition of flow and jet signal via two separate methods!
Test of Ansatz SIMULATION DATA ZYAM subtracted J(Df) Flow extinguished C(Df) = J(Df) Robust extraction of J(Df)! Both methods agree! Input jet faithfully recovered!
Particle species dependent correlations Meson-Meson (High Asymmetry) Flow anisotropy Jet asymmetry Baryon-Baryon (Low Asymmetry) Strongly particle species dependent Asymmetries and Anisotropies observed in Two-Particle Correlations
Associated particle species dependent correlation function Meson vs. Baryon associated partner (for fixed Hadron trigger) PHENIX Preliminary Differneces in asymmetry between associated meson/baryon jet functions! Similar away-side shape for associated baryon/meson jet functions! Differences in Yield for associated baryon/meson jet functions!
Yield Summary for associated identified partner correlations Meson vs. Baryon associated partner (for fixed Hadron trigger) Slope of associated meson yield vs p. T changes with centrality! Different p. T trends for associated meson and baryon yields!
Yield Summary for associated identified partner correlations Meson vs. Baryon associated partner (for fixed Hadron trigger) Away side baryon/meson ratio 2 x larger than on near side ! Strong centrality dependent trend of baryon to meson ratio! Qualitatively similar to singles ratio from PHENIX. Particle species dependent jet modification!
Trigger particle species dependent away-side modification Meson vs. Baryon trigger (for fixed Meson partner) Distribution of partner mesons per trigger-particle depends on trigger particle species in this p. T range Particle species dependent jet modification!
At higher p. T the trend appears different STAR preliminary Selection criteria: • 3. 0 Ge. V/c<p. Ttrigger<3. 5 Ge. V/c • 1 Ge. V/c<p. Tassociated<2 Ge. V/c • |h|<1 • hint of a trend: yield for “meson” triggered correlations appears to be systematically lower than for “baryon” triggers J. Bielcikova, PANIC 2005, Santa Fe
Mechanistic Details of Jet Quenching nucl-ex/0409015 What are the relative influences of: Energy-density Path-length (L, L 2, La) Need to look at problem in several different ways to pin down mechanistic details! One approach: fix e via Npart, vary path length by looking in and out of reaction plane
Complimentary Approach: Varying System Size nucl-ex/0409015 d. Nch/dh very similar for Au+Au and Cu+Cu at the same Npart ! At RHIC almost all transverse energy goes into particle production Complementary opportunity for jet-tomography: -> fix energy density -> vary path length
System Size Dependence of Jet Quenching PHENIX Preliminary Broadening of away-side jet observed in central/semicentral Cu+Cu collisions No striking differences for jet functions in Cu+Cu and Au+Au at same Npart Energy density major actor!
Novel Method to unravel Jet-Topology: Three Particle Correlations Operational Strategy to a complex Problem: Ø Get guidance from simple simulation ØGradually move to more sophisticated methodology Added topological information as compared to two particle correlations
Simulated 3 -particle jet functions (3 event mixing i. e. 2 + 1 processes not excluded) “Normal” Jet Mach cone “Deflected” Jet
Flow+Jet Experimental 3 -particle jet functions PHENIX Preliminary Jet only extinction Diagonal projection PHENIX Preliminary Horizontal projections PHENIX Preliminary Jet functions show strong away side modification -> “Mach cone” not ruled out
PID Dependence PHENIX Preliminary Hadron-Hadron (HHH) PHENIX Preliminary Strong PID Dependence observed Hadron-Meson (HMM) Hadron-Baryon (HBB)
Two Particle Jet Functions Deflected Cherenkov Recent theoretical studies indicate Cherenkov jets can also suffer from directional smearing. Satarov et al: Physics Letters B 627 (2005) 64â 70 Therefore in the sim study we introduced k. T and cone width smearing for Cherenkov jets so that the two particle jet-pair distributions look alike.
Simulation Results Coord. Syst. for Polar Plot: q f trigger Jet-axis Deflected jet - PHENIX Acceptance. Deflected jet full acceptance Cherenkov PHENIX accpt. Cherenkov full acceptance Simulations indicate characteristic signatures Analysis of the data in progress
Summary v Flow measurements give compelling evidence of strongly interacting low viscosity fluid with quark degrees of freedom v Robust decomposition techniques allow detailed study of jets Extracted jet functions indicate: • Strong away-side jet modification in h-h correlations • dependence of modification on particle species permutation v Jet modification/quenching show dependence on: • centrality, eccentricity and system size • for same Npart Au+Au and Cu+Cu show similar jet functions (similar energy density, path length not too different) v. Smooth Npart evolution of near and away side jet width v Three Particle Correlations indicate strong PID dependent modification of away-side jet, Mach Cones cannot be excluded at present. Simulations suggest that distinction between deflected jets and Mach cones is possible. v. Combination of observations crucial for elucidating mechanistic origin of jet quenching
Brazil China University of São Paulo, São Paulo 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-IN 2 P 3, Orsay LLR, Ecòle Polytechnique, CNRS-IN 2 P 3, 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 USA 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 State Technical University, St. Petersburg Sweden Lund University, Lund 12 Countries; 58 Institutions; 480 Participants* *as of January 2004 Abilene Christian University, Abilene, TX Brookhaven National Laboratory, Upton, NY University of California - 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
Particle species dependent momentum spectra in e-e collisions DELPHI Baryon yield dependence consistent with jet physics in e-e collisions
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