Jet Energy Loss In Quark-Gluon Plasma With Kinetic Theory

Since the beginning of the 21st century,people have made gradual progress in the study of the inner stucture state of matter,and our understanding of it has reached unprecedented depth and breadth,mainly due to the relativistic heavy-ion collider at Brookhaven National Laboratory in the U.S.and the Large Hadron Collider at CERN have created conditions for us to find the new state matter—Quark gluon plasma(QGP).There are two major discoveries on RHIC and LHC,one of which is the strong jet quenching phenomenon and is considered as a potential signal for QGP formation;the other is that the hot QCD plasma produced strongly coupled fluid with small viscosity.In extreme relativistic heavy ion collision experiments,high-energy partons are created in the initial stage of hard scattering.When they pass through the generated high-temperature and high-density materials,collisions occur and energy is lost.Bjorken predicted jet quenching in QCD plasma by investigating the energy loss during collisions.Subsequent studies have shown that the radiation process may be the main mechanism for the formation of jet quenching.For light quarks,the radiation energy loss is much greater than the collision energy loss.To explain heavy quark quenching,it is not enough to consider only radiation energy loss.The study of collision energy loss has rekindled people's attention.Collision is one of the main sources of dissipation.In this paper,under the framework of the transport theory including Bhatnagar-Gross-Krook(BGK)collision term,the collision effect of energy loss in fast partons traveling through the QGP is studied.In this paper,we will first derive the gluon polarization tensor within the framework of the kinetic theory associated with the BGK-type collisional kernel.We have worked out the longitudinal and transverse dielectric functions in terms of the polarization tensor.From the expression we can see that the collision effect manifested by the collision rate can be embedded in the dielectric functions.Based on the dielectric functions,we studied the polarization energy loss when the fast partons travel through the QGP.The numerical result indicates that the collision rate significantly increases the polarization energy loss.We explain the impact of the collision on the loss of polarized energy based on the relationship between the scattering cross section and the collision rate in the dynamics.