1. Background introduction Model introduction Analysis method Results and discussions Conclusions Collaborators: S. Zhang, Y. G. Ma, H. Z. Huang, X. Z, Cai, J. H. Chen, Z. J. He, J. L. Long, W. Q. Shen, X. H. Shi, J. X. Zuo. Shanghai Institute of Applied Physics Two- and Three-particle Correlations in a Partonic Transport Model Guo-Liang Ma (1)

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

3. Mach-like Structures (3)

4. Mach cone shock waves 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 Gluon radiations ( Cherenkov or Bremsstrahlung) 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)) (4)

5. 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.) (5)

6.  (1) Get raw  correlation signal in same event.  (2)Get corresponding background by mixing events in same centrality.  (3)Get  correlation by removing background with ZYAM method ( PHENIX Collaboration PRL 97, 052301 (2006)). Mixing-event Technique (6) Background Subtracted signal AMPT model

7. (7) PLB 641, 362 (2006) G. L. Ma et al. ▲ melting version with hadronic rescattering (10mb) ● melting version without hadronic rescattering (10mb) ■ STAR data 0-5% (4-6)x(0.15-4)GeV/c  Mach-like structure is born in strong parton cascade process, and furthermore developed in hadronic rescattering process.  The problem of excessive correlation magnitude.  correlations from AMPT ( (3<p T trigger <6GeV/c,0.15<p T assoc <3GeV/c) PLB 641, 362 (2006) G. L. Ma et al.

8. ■ STAR data 0-5% (4-6)x(0.15-4)GeV/c ◆ default version with hadronic rescattering ★ default version without hadronic rescattering  No splitting is seen on away side under the soft p T cut in default version (only with hadronic resacttering )!  correlations from AMPT ( (3<p T trigger <6GeV/c,0.15<p T assoc <3GeV/c) (8) PLB 641, 362 (2006) G. L. Ma et al.

9. More information from 3-particle correlation --- deflected jets or Mach cone shock waves? (9) ① deflected-jets Medium away near ② Mach cone shock waves: away near Medium Δ2Δ2 Δ1Δ1 π π 0 0 Δ2Δ2 Δ1Δ1 π π 0 0

10. 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) nucl-th/0608050, G. L. Ma et al. (1) (3)(5) (4)(2)

11. ■ PHENIX data (nucl-ex/0510019 ) □ parton cascade + hadronic rescattering ○ hadronic rescattering Parton cascade effect on 2- and 3- particle correlations 1) Hadronic rescattering mechanism alone can not give big enough splitting parameters and correlation areas. 2) Parton cascade mechanism is essential for describing the splitting amplitude of experimental Mach-like structure. 3) Large energy loss in dense partonic medium. (11) parton cascade + hadronic rescattering hadronic rescattering alone

12. Au+Au 200GeV (0-10%) Partonic Mach-like Shock Waves ? (12) nucl-th/0610088, G. L. Ma et al.

13. p T dependences of Mach-like structures (13) p T -dependent Mach-like shock waves See S. Zhang’s poster, for the detail of p T and η dependences of Mach-like structures (49, section 2).

14. Conclusions 1)Partonic Mach-like shock waves are born in the strong dynamical parton cascade and further developed in hadronic rescattering process. The problem of excessive correlation magnitude is still not solved in current AMPT model. 2)Hadronic rescattering mechanism alone can produce similar correlations, but it can not give big enough splitting parameters and correlation areas. 3)The partonic Mach-like shock waves are centrality- dependent,p T -dependent within the AMPT model. (14)

15. Thanks for your attentions! (15)