Modification of Jet Properties in Heavy Ion Collisions

1. Modification of Jet Properties in Heavy Ion Collisions Wolf Gerrit Holzmann (Nuclear Chemistry, SUNY Stony Brook) for the Collaboration

2. Outline • Introduction • General Motivation • Heavy Ion Collisions • Jet Observables & What they tell us • Jets in h+h Collisions • Jets in Au+Au Collisions • Modification of Jet Topologies in Au+Au • Summary

3. Phase Diagram for Nuclear Matter General Motivation Probe experimentally via Heavy Ion Collisions!

4. Heavy Ion Collisions at RHIC: • High Energy-density Matter Created in Au + Au Collisions ε ~ 50 - 100ε0 • Rapid Equilibration is Achieved Large Pressures ► large measured v2 • Inferred Hadronization Temperature is Consistent T ~ 176 MeV, μ ~ 40 MeV • Jets are Remarkable Probes for this High-density Matter • Auto-Generated • Calibrated • Calculable (pQCD) • Accessible statistically via correlations in Au+Au The Consequences of this High-density Should be manifestly Present

5. Fragmentation: away-side near-side Jets in h+h Collisions parton hadron hadron parton Azimuthal Correlations Carry Invaluable Information Pertaining To Jet Properties.

6. Fragmentation: Gyulassy et al., nucl-th/0302077 Jets in Au+Au Collisions Induced Gluon Radiation ~ collinear gluons in cone “Softened” fragmentation I. Vitev, nucl-th/0308028 The Predicted Influence of the Medium is Specific.

7. PHENIX Preliminary Adler et al., PRL90:082302 (2003), STAR away-side near-side Calibrated Signal d+Au Distinct Di-jet peaks observed for p + p and d + Au Extracted Di-jet properties serve as baseline

8. Conditional-Yields Area under curve fraction of pairs that are correl. jet pairs Total Area conditional yields are corrected for f-acceptance & efficiency, and are reported in the PHENIX h-acceptance ( | h | < 0.35 ). correlated jet-pairs over combinatoric background conditional yield

9. Calibrated Signal - d+Au Expected Yield Dependence

10. Measured Correlation Functions in Au+Au Associated Mesons PHENIX Preliminary Associated Baryons Au + Au Correlation Functions are Dominated by Harmonic and Jet Correlations

11. Decomposition of Correlation Function It is necessary to decompose the correlation function to obtain reliable jet yields and jet properties

12. Correlation Function Jet Function SIMULATION Out-of-plane In-plane Harmonic Correlations relative to Reaction Plane Correlations Relative to the reaction plane are used as a constraint J. Bielcikova, S.Esumi, KF, S.Voloshin, and J.P.Wurm, nucl-ex/0311007, to appear in PRC(R).

13. Fragmentation: d+Au Is there Broadening of the Away Side Jet in Au+Au Collisions? Associated charged hadrons and mesons show centrality dependent broadening of away-side jet

14. Escaping Jet “Near Side” Suppressed Jet “Away Side” q q Centrality Dependence of Cond. Jet Yields • Charged hadron yields show apparent away-side suppression • Hadron yields dominated by Mesons • Similar near- and away-side for associated baryons.

15. Centrality Dependence of Baryon to Meson Ratios The Observed baryon to meson ratio is higher for away-side jets

16. Out-plane In-plane Di-Jet Tomography X.N. Wang Angular Dependent Jet Modification should be an important observable

17. pTtrig=4.0-6.0 GeV/c, ||<1.0 2.0<pTassoc<pTtrig pTtrig=2.5-4.0 GeV/c, ||<0.35 1.0<pTassoc<2.5 GeV/c STAR Preliminary STAR preliminary color scheme: in-planeout-of-plane 20-60% 20-60% 20-60% 20-60% Di-Jet Tomography Away-side jet is suppressed and broadened

18. Nuclear Modification Factor Gyulassy et al., nucl-th/0302077 Further Test for Modification no effect 

19. Single Particle Distributions Au + Au Experiment d + Au Control Experiment Null Control Cronin effect (initial state effect) dominates in d+Au High-pT Jet Suppression dominate in Au+Au. Final Data Preliminary Data

20. The next frontier: Detailed Studies: Summary and Conclusions: • Jets observed and studied in HI Collisions via Angular Correlations • Can measure Yields, jet-shapes (jT,kT) from correlation functions • Jet quenching manifested via • suppression of conditional yields • away-side broadening • suppression ininclusive pT distribution • angular away-side suppression • Di-Jet Tomography • Flavor Composition of Jets

21. Brazil University of São Paulo, São Paulo China 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-IN2P3, Orsay LLR, Ecòle Polytechnique, CNRS-IN2P3, 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 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 St. Petersburg State Technical University, St. Petersburg Sweden Lund University, Lund 12 Countries; 58 Institutions; 480 Participants* USA Abilene Christian University, Abilene, TX Brookhaven National Laboratory, Upton, NY University of California - Riverside, 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 *as of January 2004

22. BACKUP

23. Low Energy: Squeeze-out High Energy In-plane Large Energy Density lead to pressure gradients  flow Elliptic Flow Probes the global features of the collision, Can serve to constrain the EOS Tells us something about the pressure buildup -> barometer • Measure through correlations: • reaction plane • 2-particle correlations • cumulants

24. First Application of the Azimuthal Correlation Technique at RHIC Correlation Function Method Wang et al., PRC 44, 1091 (1991) Lacey et al. PRL 70, 1224 (1993)

25. s near s far jT, kT & Correlation Functions jT ,kT & Correl.- Functions jT and kT are 2D vectors. We measure the mean value of itsprojection into the transverseplane|jTy|and|kTy|. xh = pT,assoc / pT,trigg