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PHENIX Overview

PHENIX Overview. U.S.-Japan Collaboration Site Visit. Geography. PHENIX Goals. Two Major Goals: Study “the structure of the vacuum” Closely related to physics of the early universe Key questions: Properties of the Quark-Glupn Plasma (QGP) Nature and order of the phase transition to QGP

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PHENIX Overview

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  1. PHENIX Overview U.S.-Japan Collaboration Site Visit W.A. Zajc

  2. Geography W.A. Zajc

  3. PHENIX Goals • Two Major Goals: • Study “the structure of the vacuum” • Closely related to physics of the early universe • Key questions: • Properties of the Quark-Glupn Plasma (QGP) • Nature and order of the phase transition to QGP • Origin of 98% of the msss of the proton (and neutron) • Study “the spin structure of the proton” • Logical extension of work done in Deep Inelastic Scattering • Key questions: • How much of the spin is carried by gluons? • How much of the spin is carried by anti-quarls? • One major principle • Measure simultaneously as many probes of dense matter as possible • Focus on • Self-generated probes of the plasma • Quality spectra of identified particles W.A. Zajc

  4. PHENIX Approach to QGP Detection 1. Deconfinement R(U) ~ 0.13 fm < R(J/Y) ~ 0.29 fm < R(Y ’ ) ~ 0.56 fm • Electrons, Muons 2. Chiral Symmetry Restoration Mass, width, branching ratio of F to e+e-, K+K- with dM < 5 Mev: • Electrons, Muons, Charged Hadrons Baryon susceptibility, color fluctuations, anti-baryon production: • Charged hadrons DCC’s, Isospin fluctuations: • Photons, Charged Hadrons 3. Thermal Radiation of Hot Gas Prompt g, Prompt g * toe+e-, m+m - : • Photons, Electrons, Muons 4. Strangeness and Charm Production Production of K+, K- mesons: • Hadrons Production of F, J/Y, D mesons: • Electrons, Muons 5. Jet Quenching High pT jet via leading particle spectra: • Hadrons, Photons 6. Space-Time Evolution HBT Correlations of p±p±, K± K± : • Hadrons Summary: Electrons, Muons, Photons, Charged Hadrons W.A. Zajc

  5. PHENIX-- Coming Attractions • A complex apparatus to to measure • Hadrons • Muons • Electrons • Photons One Crowded Hall One “Central Arm” W.A. Zajc

  6. PHENIX (Central) PID via TOF Executive Summary: • Superb Particle Identification for hadrons: • Measure time difference between Beam-Beam (START) counters and “TOF” wall or EmCal elements. • Beam-Beam: • 2 x 64 Cerenkov radiators + PMT’s • s ~ 50 ps • Time-of-Flight (TOF) wall: • ~ 2000 PMT’s reading out ~1000 “slats” • s ~ 80 ps • EmCal: • Both PbSc and PbGl have timing capability(greatly extends coverage) • s(PbSc) ~ 300 ps • s(PbGl) ~ 400 ps Calculation by B.A. Cole W.A. Zajc

  7. PHENIX (Central) PID via Cerenkov Executive Summary: • Superb electron/hadron discrimination • Key Features: • Ring imaging Cherenkov with gaseous radiator • Radiator gas:ethane (n = 1.00082) or methane (n = 1.00044) • Electron identification efficiency: Close to 100% for a single electron with momentum less than ~ 4 GeV/c • Pion rejection factor: > 103 for a single charged pion with momentum less than ~ 4 GeV/c • Ring angular resolution: ~ 1 degree in both q andf • Two ring separation: ~ few degrees in both q andf W.A. Zajc

  8. PHENIX Data Acquisition • Executive Summary: • A distributed system designed to read out PHENIX in a “deadtime-less” mode • Key parameters: • Recording rate: 20 MB/s • Level 1 trigger rate: 25 kHz • Au-Au rate at design luminosity: ~100 Hz W.A. Zajc

  9. Prototypical Heavy Ion Signals • Iconography: “The pictorial illustration of a given subject” (American Heritage Dictionary) • Ratings based on: • Interest generated • Relation to primordial state • Subjective impression • PHENIX: • Will measure all of these (and more) in a single experiment NA44 E859 WA80 NA50 Nota Bene: These are not the ratings of the experiments! W.A. Zajc

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