1. N. N. Ajitanand Nuclear Chemistry,SUNY, Stony Brook For the PHENIX Collaboration Three-Particle Correlations From PHENIX to Investigate the Properties of the QGP at RHIC The 20th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (QM2008) Feb. 4 – 10, 2008 Jaipur

2. N. N. Ajitanand QM20082 A Cue from Lattice QCD: Phase Transition Energy density required for QGP formation Necessary to create ε > 0.6 – 1.0 GeV/fm 3 in heavy ion collisions Necessary to create ε > 0.6 – 1.0 GeV/fm 3 in heavy ion collisions

3. N. N. Ajitanand QM20083 PRL87, 052301 (2001) Central collisions peripheral collisions time to thermalize the system (  0 ~ 0.2 - 1 fm/c)  Bjorken  ~ 5 - 15 GeV/fm 3 ~ 35 – 100 ε 0 Extrapolation From E T Distributions Achieved Energy Density is Well Above the Predicted Value for the Phase Transition Predicted Value for the Phase Transition Achieved Energy Density is Well Above the Predicted Value for the Phase Transition Predicted Value for the Phase Transition 200 GeV Au+Au Collisions studies at RHIC!

4. N. N. Ajitanand QM20084 Quark scaling of v2 indicates flow sets in at the partonic stage Strong quenching observed for high pt hadrons hydro-like flow observed High Energy Density matter produced in 200 GeV Au + Au Initial anisotropy gives large pressure gradients

5. N. N. Ajitanand QM20085 Even the phi which has a very low hadronic scattering cross-section develops a v2 which scales with the mesons. Strong indication of flow developing at the partonic stage Phi meson Flow

6. N. N. Ajitanand QM20086 The same applies to lambdas and cascades Lambda & Cascade Flow

7. N. N. Ajitanand QM20087 Observation of significant flow for the D meson which implies charm flow D Meson Flow

8. N. N. Ajitanand QM20088 G. D. Moore, D. Teaney hep-ph/0412346 Calculation of the charm spectrum and the elliptic flow as a function of the diffusion coefficient implies surprisingly strong rescattering behaviour for the heavy quark. An indication of the rather special attributes of the matter formed Charm Diffusion

9. N. N. Ajitanand QM20089 Such a low value is consistent with the observation of substantial elliptic flow and may provide the conditions for a special medium response to hard probes such as Mach flow R. Lacey et al. Phys. Rev. Lett. 98,092301 (2007) The shear viscosity to entropy ratio ( eta /s) is estimated for the hot and dense QCD matter created in 200 GeV Au+Au collisions at RHIC. A very low value is found; eta /s~0.1, which is close to the conjectured lower bound (1/4 pi ) Shear viscosity to Entropy ratio

10. N. N. Ajitanand QM200810 There is strong evidence to support the view that the medium thermalizes rapidly during the partonic stage and exhibits a high degree of collectivity. Study of the medium response to high pT probes is a natural next step

11. 11 Jets are a natural probe of the Medium In relatvistic heavy ion collisions hard parton- parton processes occur early Scattered partons propagate through the medium radiating gluons and interacting with partons of the medium Finally partons fragment, (possibly) outside the medium

12. 12 Jet Study via Assorted Correlations Associated low pT particle pT High pT Hadron Correlation Function N(pT)

13. N. N. Ajitanand QM200813 It is necessary to decompose the correlation function to obtain the Jet Function! H(v2)Obtain using BBC Reaction Plane Large η gap Two source model gives : Correlation Flow Jet Correlation Jet Sets a0 Condition Zero Yield At Minimum Evaluate a0 Phys. Rev. C 72, 011902 (2005) Ajitanand et.al. Phys. Rev. C 72, 011902 (2005)

14. N. N. Ajitanand QM200814 Simulation Test of Jet Recovery Di-jet faithfully recovered Normal Jet Shape abnormal Jet Shape Line : Input Jet Correlation Squares : Extracted Jet Correlation

15. 15 200 GeV Au+Au : Hadron Jet Shapes Jet-pair distributions resulting from decomposition show significant modification Jet-pair distributions resulting from decomposition show significant modification PRL 97, 052301 (2006) 200 GeV Au+Au 1<pT<2.5 vs 2.5<pT<4.0

16. 16 Meson vs. Baryon associated partner (for fixed Hadron trigger) Associated mesons and baryons are similarly modified as would be expected If in-medium modification is the cause of the away side bending PHENIX Preliminary

17. 17 Armesto,Salgado,Wiedemann hep-ph/0411341 Possible Modifications of Jet Topology Mach Cone,Wake Effect or “sonic boom” Stoecker nucl-th/0406018 Muller,Ruppert Hep-ph/0503158 Casalderrey-Solana, Shuryak, Teaney, arXiv hep ph/0411315 (2004) Flow induced Deflection Cherenkov Cone A. Majumdar Hard Probes 2006

18. N. N. Ajitanand QM200818 Three Particle Correlations Used to Extract Jet Topology One high pT hadron 2.5<pT<4.0 GeV/C with two low pT hadrons 1.0<pT<2.5 GeV/c Real Triplets formed from one event Correlation Function Correlation Function Fake Triplets formed from 3 events Total 3P jet = True 3P jet + (2+1) jet True 3P jet : all 3 particles belong to the same di-jet (2+1) jet : 2 particles belong to same di-jet, third one does not

19. 19 along azimuth Polar plot 3 Particle Correlations in High pT Framework (*) Normal Jet Same Side Away Side Assoc. pTs (2,3) *  12 *  = along radius *  12 *  13 *  _ = Hi pT(1)

20. Deflected jet sim 3-Particle di-jet correlations allow a distinction between different mechanistic scenarios ! Mach Cone sim Deflected and Cone Jet Sims 2-particle Correlations matched High pT(1)

21. 21 PHENIX SIM Test of Harmonic removal Jet+Harmonic ZYAM gives good Jet Recovery Input Jet Harmonic removed Jet Correlation = Total Correlation – a0*(Harmonic Correlation) “ao” is adjusted till Jet Correlation surface goes to zero at its minimum (ZYAM ) Phys. Rev. C 72, 011902 (2005) Ajitanand et.al. Phys. Rev. C 72, 011902 (2005)

22. Blue : Input Red : Recovered True 3P correlations successfully recovered (2+1) correlations obtained taking 2P in event 1 and 1P from event 2 For data relative amounts of soft-soft and hard-soft correlations set by relative strengths of observed 2P correlations True 3P Correlations absent True 3P Correlations present Test of (2+1) removal (2+1) processes successfully removed Flat Correlation Surface (offset added)

23. N. N. Ajitanand QM200823 Pairs per trigger from Correlation Pairs per trigger Input Pairs/trigger can be calculated from correlation function knowing detected singles and detected triplets

24. N. N. Ajitanand QM200824 0-5 %5-10 %10-20 % 20-40 % 40-60 % 60-90 % 200 GeV Au+Au Run 7 PHENIX Preliminary 3-particle Correlations without harmonic removal

25. Total 3-particle Jet Correlation Strong away side modification in both total and true 3P Jet Correlations Radial section True 3-particle Jet Correlation Jet Correlations

26. Data Simulated Deflected jet Simulated Mach Cone The data validates the presence of a Mach Cone away-side jet but does not rule out contributions from other topologies. Total 3P jet correlations True 3P jet correlations Azimuthal Sections

27. 27 trigger 10 deg in-plane Jet+flow Input Jet flow (Jet+flow) – flow (ZYAM) Radial Projection SIM Studies of trigger oriented with respect to Reaction Plane Reaction Plane Dispersion 0.8 (obtained in Run 7)

28. N. N. Ajitanand QM200828 trigger out-of-plane Jet+flow Input Jet flow (Jet+flow) – flow (ZYAM) Radial Projection

29. N. N. Ajitanand QM200829 Simulated LHC Event Phi Eta Et Phi Et Eta (PYTHIA + HIJING) PYTHIA Jets Jetfinder algorithms

30. 30 Start Step 1 Step 8Step 20 PYTHIA Jet A novel method of jet location in an event has been developed which utilizes successive filtering of soft background using other events Soft background

31. N. N. Ajitanand QM200831 Expected triplet jet correlation function for Mach flow signal in LHC events Once hard jet candidates have been identified in a large number of events, the three-particle correlation method can be applied to look for medium modification

32. N. N. Ajitanand QM200832 Tsunami : Nature’s awesome medium response to a hard event !!

33. Conclusions The high pt frame is a suitable choice for the study of jet topology via 3-particle correlations 3-particle jet correlations obtained for 200 GeV Au+Au 3-particle correlation without harmonic removal for most central case shows abnormal jet topology 3-particle Jet correlations show strong away side modification True 3-particle jet correlations validate presence of Mach Cone jets but do not rule out small contributions from other topologies. Major implication on limiting viscosity of sQGP Method a potential tool for jet study at LHC The much improved Reaction Plane resolution achieved in the high statistics run 7 will allow RP associated cuts on the high pT particle