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Henrik Tydesjö May 5 2004 O UTLINE - The Quark Gluon Plasma - The Relativistic Heavy Ion Collider (RHIC) The PHENIX Experiment - QGP Signals Event-by-Event Net-Charge Fluctuations Simulations PHENIX Analysis
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Phase Diagram of Nuclear Matter Early Universe Hadron Gas QGP Neutron Stars ??? Ultra-Relativistic Heavy-Ion Collisions ??? Henrik Tydesjö May 5 2004
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Q UARK G LUON P LASMA D ECONFINEMENT PHASE TRANSITION Henrik Tydesjö May 5 2004
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Q UARK G LUON P LASMA C HIRAL S YMMETRY R ESTORATION C HIRAL S YMMETRY R ESTORATION Quark Masses 0 Henrik Tydesjö May 5 2004
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Relativistic Heavy Ion Collider (RHIC) Au+Au Collisions 100 AGeV per beam Henrik Tydesjö May 5 2004
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~ 460 Members 57 Institutions 12 Countries ~ 460 Members 57 Institutions 12 Countries Collaboration Henrik Tydesjö May 5 2004
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Central Magnet Beam-Beam Counters Muon Arm Spectrometers Central Arm Spectrometers Henrik Tydesjö May 5 2004
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Central Arms Pad Chambers Charged Particle Tracking Electron, Photon Detection Hadron Identification Henrik Tydesjö May 5 2004
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Pad Chambers - Multi-Wire Proportional Chambers - Fine Granularity Pixel Pad Readout - Provide Space Points for Track Recognition Henrik Tydesjö May 5 2004
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Pad Chambers - Multi-Wire Proportional Chambers - Fine Granularity Pixel Pad Readout - Provide Space Points for Track Recognition - 172,800 Readout Channels - Chip-On-Board Technique Readout Cards (ROCS) Placed on the Chambers - Data Transfer via Fiber Optic Links Readout Card (ROC) Henrik Tydesjö May 5 2004
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Event Display Central Au+Au Collision ~ 400 tracks in central arms Henrik Tydesjö May 5 2004
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QGP SIGNALS - Jet Quenching - J/ Suppression - Strangeness enhancement - Thermal photon production - Light vector meson decays - Fluctuation probes
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- Jet Quenching - J/ Suppression - Strangeness enhancement - Thermal photon production - Light vector meson decays - Fluctuation probes Henrik Tydesjö May 5 2004 QGP SIGNALS
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Henrik Tydesjö May 5 2004 QGP SIGNALS - Jet Quenching - J/ Suppression - Strangeness enhancement - Thermal photon production - Light vector meson decays - Fluctuation probes
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N ET C HARGE F LUCTUATIONS Event-by-Event Net Charge Fluctuations in Local Regions of Phase Space Decrease of Fluctuations proposed as a signal for the QGP Predictions range up to an 80% reduction Henrik Tydesjö May 5 2004
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N ET C HARGE F LUCTUATIONS charge more evenly spread in plasma, due to the fractional charges of quarks HADRON GAS QGP
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N ET C HARGE F LUCTUATIONS Charge q in each event: Variance of q: Random Particle Emission: Normalized Variance: Henrik Tydesjö May 5 2004
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N ET C HARGE F LUCTUATIONS Henrik Tydesjö May 5 2004 Hadron Gas : QGP (assuming thermal distributions) : Hadronized QGP (from theorist calculation) : BUT HEY!!! WAIT A MINUTE!!! Wouldn’t this depend very much on acceptance?
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N ET C HARGE F LUCTUATIONS SIMULATION Charge is globally conserved Henrik Tydesjö May 5 2004
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N ET C HARGE F LUCTUATIONS SIMULATION Efficiency Dependence Henrik Tydesjö May 5 2004
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N ET C HARGE F LUCTUATIONS SIMULATION Uncorrelated Background Contribution Henrik Tydesjö May 5 2004
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N ET C HARGE F LUCTUATIONS SIMULATION Decays of Neutral Resonances (e.g. , ) introduce positive correlations between n + and n – width = 30º Henrik Tydesjö May 5 2004
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N ET C HARGE F LUCTUATIONS SIMULATION Decays of Neutral Resonances f res = 0.3 Henrik Tydesjö May 5 2004
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N ET C HARGE F LUCTUATIONS SIMULATION Simple QGP model: producing 2 or 3 pions, separated in azimuth (Gaussian width=10º) Henrik Tydesjö May 5 2004
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N ET C HARGE F LUCTUATIONS RHIC 1 st run period ~ 500 000 events |z vertex | < 17 cm p T > 200 MeV/c Henrik Tydesjö May 5 2004
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b Centrality of Collision Impact parameter, b < 10 fm Henrik Tydesjö May 5 2004 ~
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N ET C HARGE F LUCTUATIONS BBCs used for triggering corresponding to 92% of inelastic cross-section Centrality classes determined from BBC+ZDC information 0-5% 5-10% Henrik Tydesjö May 5 2004
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N ET C HARGE F LUCTUATIONS p T, of positive and negative particles Henrik Tydesjö May 5 2004
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N ET C HARGE F LUCTUATIONS Reduction not as large as predicted for QGP Consistent with resonance gas Global Charge Conservation 10% most central events Henrik Tydesjö May 5 2004
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N ET C HARGE F LUCTUATIONS Fluctuations independent of centrality 10% most central events: Henrik Tydesjö May 5 2004
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S UMMARY - An introduction was given to: Quark Gluon Plasma Relativistic Heavy-Ion Collider (RHIC) PHENIX Experiment - The behavior of Net-Charge Fluctuations in different scenarios was described in simulations - Results on Net-Charge Fluctuations in PHENIX was presented: Fluctuation result below pure global charge conservation Reduction not as drastic as predicted for a QGP Consistent with resonance gas prediction Henrik Tydesjö May 5 2004
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