The Nuclear Modification Factor Of Au+Au Collision In RHIC Beam Energy Scan Region

RHIC beam energy scanning(BES)project was designed to study the QCD phase diagram.The beam energy scanning project has three main objectives,one of them is to find signals in the formation of quark-gluon plasma.The nuclear modification factor can be used to study the relationship between nuclear-nuclear collisions and nucleon-nucleon collisions.In the RHIC beam energy scan experiment,it is used to study the quark-gluon plasma.The initial nuclear modification factor is calculated from the results of nuclear-nuclear collisions and nucleon-nucleon collisions in the same conditions,but it is difficult to achieve it in experiments.The researchers in RHIC proposed to use the results of central collision and peripheral collisions Au+Au to calculate the nuclear modification factor.There are differences between the two kinds of nuclear modification factor.In this paper,the differences in the distribution of the two kinds of nuclear modification factor with transverse momentum and the reasons for their differences are analyzed.The Glauber model is based on the concept of mean free path and the primary baryon-baryon section assumption.It provides a quantitative description of the geometry of the collision.We use it to calculate the nuclear modification factor.In Au+Au collisions,Most of the particles are in the low transverse momentum region.It is important to study the properties of the nuclear modification factor in the low transverse momentum region.This paper simulation the distribution of the nuclear modification factor with the transverse momentumn of Au+Au collisions and p+p collisions at part of the BES energy using the AMPT string melting model.The complete collision process,the collision without hadron cascade process and that without parton cascade process are simulated at the beam energy of 14.5Ge V.The relationship between the hadron cascade process,the parton cascade process and the two kinds of modification factor is analyzed.The differences of the distribution of the two kinds of nuclear modification factor with the transverse momentumn and the reasons for their differences are analyzed.The complete collision process and the collision process without hadron cascade are simulated at different beam energy.The energy dependence of the nuclear modification factor with the transverse momentum distribution is studied and analyzed,the influence of the hadron cascade process to the energy dependence is also analyzed.Finally,the relationship between the nuclear modification factor with the transverse momentum distribution and the species of particles is analyzed.