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RHIC: Physics Results

RHIC: Physics Results. Gunther Roland. IV International Symposium on LHC Physics and Detectors Fermilab 5/1-5/3 2003. Exploring QCD with Heavy Ions. I. II. III. IV. Early Universe. II. Temperature (MeV). Quark-Gluon Plasma. Structure of Relativistic Nuclei

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RHIC: Physics Results

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  1. RHIC: Physics Results Gunther Roland IV International Symposium on LHC Physics and Detectors Fermilab 5/1-5/3 2003

  2. Exploring QCD with Heavy Ions I II III IV Early Universe II Temperature (MeV) Quark-Gluon Plasma Structure of Relativistic Nuclei Mechanism of Entropy Production QCD phase diagram Properties of QGP I III 200 Critical Point IV Phase Boundary Hadron Gas Atomic Nuclei 0 0 1 Matter Density mB (GeV)

  3. Interlude: Collision Geometry Participant Region Spectators b 2R ~ 15fm Spectators Smaller Impact Parameter b More Participants (Npart) Bigger Collision System More Produced Particles!

  4. Relativistic Heavy Ion Collider First Physics in ‘00 Versatile machine • Au+Au (‘00-’02) • 19.6 GeV • 56 GeV • 130 GeV • 200 GeV • p+p (‘02,’03) • 200 GeV polarized • d+Au (‘03) • 200 GeV • 4 Experiments • 2 big • 2 small • Complementary capabilities

  5. Large acceptance tracking detector Mass, charge and momentum for >1000 hadrons per event STAR

  6. PHENIX • High Rate, Particle ID, Triggering • Rare particles: Leptons, High pT

  7. PHOBOS • Full Acceptance Multiplicity Detector • High precision spectrometer near y=0 (low pT)

  8. Particle Production at small angles High resolution spectrometer & good particle ID BRAHMS

  9. Bulk Particle Production @ RHIC • Initial Conditions/Energy Density • Thermalization • Hadro-Chemistry • Expansion Dynamics

  10. 4-p Multiplicity at RHIC BRAHMS PLB 523 (2001) 227, PRL 88 (2002) 202301 BRAHMS 130 GeV BRAHMS 200 GeV dN/dh Nice agreement! PHOBOS nucl-ex/0210015 200 GeV 19.6 GeV 130 GeV PHOBOS PHOBOS PHOBOS dN/dh Pseudo-rapidity

  11. Energy Density W. Busza, Moriond ‘03 Density of Particles Produced at y=0 Total energy released ~2000GeV Max. initial overlap volume Initially released energy density ~ 5GeV/fm3 Note: energy density inside proton ≈ 0. 5GeV/fm3 Energy of Collision

  12. 2*v2 Azimuthal Angle (rad) Interaction! Final State Anisotropy Momentum Space Azimuthal Anisotropy “Head on” view of colliding nuclei Peripheral Central Initial State Anisotropy Coordinate Space

  13. PHOBOS Anisotropy v2 vs Centrality STAR || < 1.3 0.1 < pt < 2.0 PHENIX Consistent results Hydro-limit reached for mid-central collisions from R. Snellings

  14. Bulk Particle Production @ RHIC • Initial Conditions/Energy Density: > 5 GeV/fm3 • Thermalization: • Hadro-Chemistry • Expansion Dynamics

  15. Charged Particle Spectra Th. Ullrich QM’02 Results (largely) consistent Clear Mass Hierarchy of Slopes

  16. STAR Preliminary Multi-Strange Particles J. Castillo SQM’03

  17. Statistical Model Fit Relative Abundance: Two Parameters !

  18. Bulk Particle Production @ RHIC • Initial Conditions/Energy Density: > 5 GeV/fm3 • Thermalization: • Hadro-Chemistry: Tch ~ 180 MeV, mB~25MeV • Expansion Dynamics

  19. ‘Hydro’ Fits to Spectra Simultaneous Fit to p,k,p gives Kinetic Freeze-Out Temperature, Transverse Expansion velocity

  20. ‘Hydro’ Fit to Correlation Data Consistent Data from STAR, PHENIX, PHOBOS Also HBT vs reaction plane Unlike particles Balance Functions Short-lived Resonances Consistent Results Lifetime ~ 10 fm/c Particle emission over few fm/c Fabrice Retiere SQM ‘03, Mike Lisa

  21. Bulk Particle Production @ RHIC • Initial Conditions/Energy Density: > 5 GeV/fm3 • Thermalization: • Hadrochemistry: Tch ~ 180 MeV, mB~25MeV • Expansion Dynamics: Tth ~ 110 MeV, <bT> ~ 0.6c <tfo>~ 10 fm/c, Dtfo~ 0-3 fm/c

  22. Bulk Particle Production @ RHIC • Initial Conditions/Energy Density: > 5 GeV/fm3 • Thermalization: • Hadrochemistry: Tch ~ 180 MeV, mB~25MeV • Expansion Dynamics: Tth ~ 110 MeV, <bT> ~ 0.6c <tfo>~ 10 fm/c, Dtfo~ 0-3 fm/c Consistent Description of Final State But we’re missing a picture of Dynamical Evolution

  23. II. Dense Matter Diagnostics @ RHIC • Jets • Virtual and Real Photons • Quarkonia

  24. Hadrons Hadrons q q q q Hadrons Hadrons Leading Particle Leading Particle Dense Matter Diagnostics Study fate of jets in dense matter in Au+Au Jet cross-section calculable in QCD Leading Particle Leading Particle

  25. Opal e+e- STAR Au+Au

  26. Hadrons Hadrons q q q q Hadrons Hadrons Leading Particle Leading Particle Dense Matter Diagnostics Study fate of jets in dense matter in Au+Au Jet cross-section calculable in QCD Leading Particle Leading Particle Poor man’s jet: Leading Particles

  27. “Jet Quenching” at High pT expected proton+proton observed Au+Au Yield at high pT in AA is 6 times smaller than expected

  28. Hadrons q q Hadrons Leading Particle Jets in Dense Matter Leading Particle Are we really looking at jets? • Look for jet structure by measuring • small angle correlations • back-to-back correlations relative to high pT leading particle

  29. Peripheral Au+Au data D. Hardtke QM ‘02 • Jets seen in peripheral Au+Au and p+p • Azimuthal correlations • Small angle (Df ~ 0) • Back-to-Back (Df ~ p)

  30. Central Au+Au data D. Hardtke QM ‘02 • Disappearance of back-to-back correlations in central Au+Au • Away-side particles absorbed or scattered in medium

  31. STAR “Instant” Thermalization E. Shuryak, nucl-th/0112042 Peripheral Limit (lmfp = 0) High pT particles produced early: Biggest anisotropy Central

  32. To fully preserve anisotropy: Instant formation of dense system (lmfp small) Why “instant”? Once washed out, anisotropy can’t be recovered! Thermalization timescale t=0 time

  33. Peripheral Central Anisotropy in Parton Cascade HIJING x 80 HIJING x 35 HIJING x 13 HIJING x 1 hydro , sBC 0.1 Anisotropy 0.06 Molnar, Gyulassy 0.02 Parton cascade can describe data… …if cross-sections are multiplied by 13!

  34. “Proton puzzle” ?

  35. Understanding low vs high pT Fries, Mueller, Nonaka,Bass nucl-th/0301087

  36. III. RHIC in Context

  37. A+A e+e- <Nch>/e+e- Fit pp/pp (Mueller 1983) Central A+A Total Multiplicity vs. Beam Energy PHOBOS QM’02, Steinberg

  38. Nucl. Phy. A697: 902-912 (2002) Chemistry vs sqrt(s)

  39. A+A e+e- pp/pp Asymptotic region at RHIC? Universality? Energy Hadrons e+e- What about strangeness?

  40. Mid-Rapidity K/ NA49 (V. Friese SQM’03) Non-monotonic Evolution! Oeschler et al: Thresholds vs Baryo-chemical potential

  41. Kaon Slope Parameters NA49 (V. Friese SQM’03) PHENIX PHENIX NA49 NA49 AGS AGS

  42. Summary • Extensive and Consistent Data Sets • BRAHMS, PHENIX, PHOBOS, STAR • AGS, SPS, RHIC • Consistent and Concise description of Final State • Bulk particle production • Intermediate pT spectra + correlations • Challenge: Consistent Dynamical Scenario • What makes all this happen in 10fm/c?

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