| High-energy heavy ion collision physics refers to when two heavy nuclei collide with each other,a fresh architecture of high temperature and high density is resulted.When the temperature of the high-temperature high-density system drops to the phase transition point,the hadronization of quarks and gluons occurs and converts to quasiparticles,and when the temperature of the high-density system drops to the temperature of thermal freezing,the quasi-particles in the collision area of the heavy core particles escape to form free particles,The difference in mass between quasiparticles and free particles is called the mass shift effect.In previous discussions of HBT correlation functions,the selection of particle emission sources is mostly completely chaotic,however,In the recent analysis of Pb-Pb collision experimental data by the ALICE experimental Group,there were 23% ±8% coherent emission fractions in the particle emission sources π,it can be seen through experimental facts that the particle emission source model is generally defined as the chaotic source model,which no longer conforms to the facts,therefore,the purpose of this paper is to derive the formula of the two-particle HBT association function containing mass displacement effect by selecting a partially coherent model as the particle emission source model,the influence of media mass width,particle emission source chaos parameter and particle emission source expansion velocity on the correlation function of two particles under partial coherent source conditions is analyzed.The results show that the correlation intensity of the two particles increases with the increase of the momentum of the particles,while the influence of the mass width on the associated intensity does not change significantly with the increase of the momentum of the particles,and the strength of the two-particle association growth apparently with the growth of the chaos parameter at the large momentum.We concluded that in the small momentum region,the rate of expansion increased the value of the twoparticle correlation function,which was consistent with the analysis of the experimental data.However,for large-momentum particles,the expansion rate inhibits the correlation function of two particles,and the effect of relativistic effects on the correlation function should be considered. |
