Research On The Production Of Final State Particles In The Color Glass Condensation Theor

Quantum Chromodynamics（QCD）shows that a high temperature and high density environment will produce in the central region of the relativistic heavy ion collisions.This can induce the normal hadronic matter transition to quark gluon plasma（QGP）.At present,in high energy nuclear physics,people study the formation and evolution of QGP which is the hot research point.Based on different frameworks of theories,physicists set up many models to study QGP,such as color glass condensate（CGC）model and perturbative QCD model（p QCD）.Under certain uncertainties,these models can provide a good description of experimental data.But physicists are still not very clear about the QGP formation and evolution mechanism.In the 1990s,in order to describe the phenomenon of gluon saturation,physicists propose the CGC effective theory.Before the relativistic heavy ion collisions,the density of gluons within nucleon will increase with the increase of energy or decrease of Bjorken.In the high energy limit（is sufficiently small）,the number of gluons produced per unit phase space becomes very many,and many gluons squeezed begin to overlap.At this point,nonlinear effects dominate,so that the density of gluons does not increase indefinitely to reach a state of dynamic equilibrium,gluon saturation state.In recent years,physicists have also found evidences of the existence of gluon saturation state in experimental study.Therefore,the study of the particles（hadrons）production based on the framework of CGC effective theory has become a hot point in the research field of high energy nuclear physics.In order to have a deeper understanding of QGP,in this paper,we use the6)-factorization hadron production model to study hadron production in the relativistic heavy ion collisions based on the framework of CGC effective theory.The collinearly-improved Balitsky-Kovchegov（ci BK）equation evolved unintegrated gluon distribution（UGD）is used,for the first time,to study the hadron productions in the relativistic heavy ion collisions in order to improve the predictive power of CGC ef-fective theory.We show that the ci BK equation evolved UGD provides a relatively better description of the LHC data on the transverse momentum and rapidity distributions of charged hadron and neutral pion productions for several collision energies,as compared to the running coupling Balitsky-Kovchegov（rc BK）equation evolved UGD,since the the ci BK evolved UGD has a sharper transverse momentum distribution than the rc BK one.The impact of running coupling prescriptions on hadron productions are studied.It shows that the parent dipole and smallest dipole running coupling prescriptions give a similar depiction of the data.Moreover,the scale dependence of the fragmentation func-tion is investigated by taking three typical value of scales.We find that the differences resulting from the scale dependence and the accuracy sensitivity of the fragmentation function can be fully absorbed into the normalization factorwhich lumps higher order corrections.