1. Effect of parton cascade to the medium Hanlin Li IOPP, CCNU, Wuhan Fuming Liu IOPP, CCNU, Wuhan Xin-Nian Wang LBNL, USA Yan Zhu IOPP, CCNU, Wuhan QNP, Beijing, September 21 － 26, 2009

2. 2/14 OUTLINE Introduction Preliminary results Elastic energy loss Medium modification caused by jet propagating Conclusions and Outlook

3. 3/14 Introduction — jet quenching Jet quenching is a good probe of sQGP. Suppression of High P T hadrons. It’s also important to study the modification of medium due to jet propagation. Azimuthal angle correlation caused by jet medium interaction.  Several models:  Putting a source current in hydrodynamic (Chaudhuri and Heinz,2006);  Markovian parton scattering (MPS) model (Charles B. Chiu and Rudolph C. Hwa,2006).  ……

4. 4/14 By now only elastic collisions are considered. where and Our approach — Parton cascade simulation based on Boltzmann Eq.

5. 5/14 Elastic collision rate: Energy distribution of thermal parton: Interaction amplitude: Interval between successive collisions : More useful formulae Gyulassy and Wang, Nucl.Phys.B420,583

6. 6/14 Test our MC with numerical integration Set jet moving along z-axis  Energy distribution of produce partons from single scattering for different energy of jet E 1.  Angle (theta=ATAN(pz/E) ) distribution of produce partons from single scattering for different energy of produce particle. E 1 =20GeV

7. 7/14 Elastic energy loss for qq collision w/o. s.a.a. w. s.a.a. Theory (X.N. Wang,Phys.Rept.280:287-371.)

8. 8/14 Modification of medium by propagating jet t=2fm/c Jet moves along z-axis. r=sqrt(x 2 +y 2 )

9. 9/14 Modification of medium by propagating jet t=4fm/c

10. 10/14 Modification of medium by propagating jet t=8fm/c

11. 11/14 Azimuthal angle distribution — single scattering Jet moves along z-axis. Ф=ACOS(pz/sqrt(pz 2 +px 2 ))  Double-peak appears in single scattering.  Azimuthal angle distribution is energy dependence. pro.  Double-peak appears in single scattering.  Azimuthal angle distribution is energy dependence.

12. 12/14 Azimuthal angle distribution — multiple scattering  Double-peak at the early time as single scattering  Uniform distribution after enough time. Double-peak disappears due to the interaction of associate partons. t=15fm/c t=4fm/c t=1fm/c

13. 13/14 Conclusions and Outlook  A parton cascade simulation has been construced based on Boltzmann eq..  Elastic energy loss has been investigated. Strict calculation shows a lower energy loss than that in previous work.  Cone structure of produced parton can be formed when jets propagate in the medium.  The azimuthal angle distribution of produced partons depends strongly on their energy and the medium size. More realistic medium will be used. Inelastic collision(2 3) will be included.

14. 14 Thanks for your attention!

15. 15 Azimuthal angle correlation —single scattering Jet move along z-axis. Ө =ATAN(p z /E) Azimuthal correlation is energy dependence.

16. 16 Multiple scattering exclude scattering among thermal partons