Pseudorapidity Dependence Of Matter Evolution In High Energy Collisions

The relativistic heavy ion collider(RHIC)and the large hadron collider(LHC)provide the conditions for the exploration of quark matter.The experimental collaborations measure transverse momentum and pseudorapidity distributions of particles in the Xe-Xe,p-p,and p-Pb collision systems.To further understand the high energy collisions,we use statistical model to analyze the spectra of these particles and find the matter evolution and the production process of particles.In this work,we study the Xe-Xe collision at(?)=5.44 TeV,p-p collision at(?)=8 TeV,and p-Pb collision at(?)=8.16 TeV and at(?)=5.02 TeV,respectively.On the basis of the analysis of transverse momentum distribution,we focus on the pseudorapidity spectrum.For p-p and p-Pb collisions,we give the reaction structure pictures at the momentum space,rapidity space and velocity space.We divide the work into the following two parts.In the first part,we discuss the Xe-Xe collision at(?)=5.44 TeV by using the multisource thermal model and the fireball model,respectively.We study the dependence of transverse momentum spectrum and pseudorapidity distribution on different centrality.In the multisource thermal model,we combine Tsallis statistics with the structure of the collision system to investigate the particle production in Xe-Xe collision.By studying the transverse momentum spectra of ?,K and p produced in the collision,we obtain the system temperature and non-equilibrium degree,which vary with the centrality and particle mass.Based on these results,we obtain the pseudorapidity distribution of many charged particles.In the fireball model,we extract the temperature and the non-equilibrium degree of the system by analyzing the transverse momentum distribution.We combine Tsallis statistics with q-Gaussian function to obtain the pseudorapidity spectrum of particles,and analyze the position of the middle peak of the pseudorapidity spectrum and the width of the pseudorapidity distribution.The results of the two models are consistent with the experimental results.In the second part,we use the multisource thermal model to discuss the particle production in p-p collisions at(?)=8 TeV and(?)=5.02 TeV and in p-Pb collisions at(?)=8.16 TeV and(?)=5.02 TeV.We also study the collision centrality dependence of the transverse momentum distribution and the pseudorapidity distribution.The model results keep consistent with the experiment results.Based on the particle production of the multisource thermal model,the transverse momentum distributions of ?,K and p are analyzed.We obtain the temperature and non-equilibrium degree of the system,which vary with the centrality,the collision energy and the particle mass.Based on transverse momentum distribution and pseudorapidity spectrum,the momentum,rapidity and velocity are extracted.In the momentum space,rapidity space and velocity space,the two-dimensional structure pictures of the reaction system are given.They can directly reflect the matter evolution in the collisions.