1. Background introduction Model introduction Analysis method Results and discussions Conclusions G.L. Ma, S. Zhang, YGM et al., Phys Lett B 641, 362 (2006) G.L.Ma, YGM, S. Zhang et al., arXiv:nucl-th/0608050, sub to PLB G.L.Ma, S. Zhang, YGM et al., arXiv:nucl-th/0610088, sub to APS Y.G. Ma, G.L. Ma, S. Zhang, X. Z. Cai, H. Z. Huang et al. Shanghai Institute of Applied Physics, CAS Two- and Three-particle Correlations in a Partonic Transport Model (1

2. Di-hadron correlations p T (assoc) > 2 GeV/c p T (assoc) > 0.15 GeV/c 4 < p T (trig) < 6 GeV/c Soft associated particles → enhancement Hard associated particles → suppression Associated particles On away side : (2

3. Soft Associated particles on Away side (thermalization) near side away side thermalization??? thermalized What happens to a hard probe that traverses a colored medium? softened + broadened =?= thermalized (3 from away jets from medium decay SOFTENED BROADENED

4. Mach-like Structures (4 NPA 774, 581 (2006) PRL 97, 052301 (2006)PHENIX

5. Wake Effect or “sonic boom” NPA 750, 121 (2005) Stöecker hep-ph/0411315, hep-ph/0602183 Casalderrey-Solana PLB 618, 123 (2005) J. Ruppert PRC 73, 011901(R) (2006) T. Renk PRL 97, 062301(2006) A. K. Chaudhuri PRC 72, 064910 (2005) Armesto Correlation of Jet with flowing medium Cherenkov gluon radiation PRL 96, 172302 (2006) Koch, Majumder, X.-N. Wang PLB 630, 78 (2005) I. Vitev NPA 767, 233 (2006) I.M. Dremin Possible interpretations of Mach-like structures Θ emission = arccos (c s /c) Θ emission = arccos (1/n(p)) (5

6. AMPT model (1) Default AMPT Model (2) Melting AMPT Model a multi-phase transport model (by C. M. Ko and Z. W. Lin et al.) (6

7.  (1) Get raw  correlation signal in same event.  (2)Get respective background by mixing events in same centrality.  (3)Get  correlation by removing background with ZYAM method. Mixing-event Technique Background Subtracted signal (7

8.  correlations from AMPT ( (3<p T trigger <6GeV/c,0.15<p T assoc <3GeV/c) (1) ▲ melting version after hadronic rescattering (2) ● melting version before hadronic rescattering (3) ◆ default version after hadronic rescattering (4) ★ default version before hadronic rescattering (5) ■ Star Data 0-5% (4-6)*(0.15- 4)GeV/c factor=1.58 Au+Au 200GeV (0-10%) (8

9. Mach-like Structures in AMPT model  correlations in Au+Au 200GeV (  correlations in Au+Au 200GeV (2.5<p T trigger <4GeV/c,1<p T assoc <2.5GeV/c) Mach-like Structures in AMPT model  correlations in Au+Au 200GeV (  correlations in Au+Au 200GeV (2.5<p T trigger <4GeV/c,1<p T assoc <2.5GeV/c) D (9

10. Is there conical flow? away near Medium mach cone Medium away near deflected jets hard-soft-corr + soft-bkgd. soft-soft-corr in underlying event. trigger soft bkgd assoc 3-4 GeV/c1-2 GeV/c flow modulated background: 3-particle correlation Medium away near di-jets  1  2  1  2

11. Three-particle correlations in AMPT mix-event technique background subtracted 3-particle correlation signal ( (2.5<p T trigger <4GeV/c,1<p T assoc <2.5GeV/c) (10

12. The N part dependences of three-particle correlations 3-particle correlation density definition: (11

13. What happens for p+p?  No Mach-cone behavior!

14. Correlations between forward- and mid-rapidity in d+Au collisions STAR Preliminary Mid-rapidity Forward-rapidity trig. asso.

15. Parton cascade effect on 2- and 3- particle correlations (1)Hadronic rescattering mechanism also can produce 2- and 3-particle correlations, but it can not give big enough splitting parameters. (2) Parton cascade mechanism is essential for describing the amplitude of experimental mach-like structure. (12

16. Time Evolution of Mach-like Structures in AMPT model  At least a lifetime of partonic matter of 1.5 fm/c is needed for the birth of Mach- like structures for 10mb. parton cascade hadronic rescattering Lifetime(13

17. Au+Au 200GeV (0-10%) Partonic Mach-Like Shock Waves ?(14

18. (15 p T dependences of Mach-like structures(15 p T -dependent Mach-like shock waves

19. ? ? √ ??? η dependences of Mach-like structures PHOBOS (16

20. 1) Special trigger particles and associated particles 2) System-size dependence including d+Au and p+p 3) Δη and ridge- correlations Conclusions and Outlook 1) Partonic Mach-like shock waves are born in the strong parton cascade and further developed in hadronic rescattering process. 2) Hadronic rescattering mechanism can produce similar correlation, but it can not give big enough splitting parameters and correlation areas. 3) The partonic shock waves are centrality- dependent,p T -dependent and η -dependent. (17 Outlook: Conclusions: