The Study For Fluctuations And Correlations Of Conserved Charges In Relativistic Heavy Ion Collision From JAM Model

From ancient times to the present, Humans keep exploring the mysteries of the world. The elementary particles and the interaction between the elementary particles of the constituent material is one of the basic problems that humans have been exploring.Heavy ion collision is an important method to study extreme high temperature and high density environment, In the case of high temperature and high density, the system may have a change called phase transition, namely from the hadron state transfer to the quark gluon plasma state. As a new matter ,QGP has led to the forefront of physics research boom. The Relativistic Heavy Ion Collider at the Brookhaven National Laboratory accelerates heavy ions and collides them to produce extreme environments with high temperature and high density, make it possible to study the QCD phase diagram and to study the properties of quark gluon plasma.There are four fundamental interactions in the nature : the strong interaction, the weak interaction, the electromagnetic interaction and the gravitational interaction, where it is the strong interaction that confines the quarks and gluons in the hadrons. Quantum Chromodynamics can successfully explain plenty of physics phenomena and is considered to be the correct theory of strong interaction. The phase structure of the nuclear matter described by the strong interaction can be expressed by the QCD phase diagram. The QCD phase diagram is a two-dimensional structure. The abscissa represents the chemical potential( ?B) and the ordinate indicates the temperature( T ). The finite temperature lattice QCD calculation predict that it is a smooth cross-over transition at high temperature and small chemical potential( ?B) region , however , the first phase transition occurs in the hadron phase to the QGP phase at high chemical potential. With the increase of the baryon chemical potential and the increase of temperature, there is an initial point along the boundary of the first order transition. The initial point is called the critical point.The fluctuation and correlation of conserved quantities are very sensitive observations for studying the QCD phase transitions and critical points in heavy ion collisions. Recently, the QCD calculations show that the fluctuation of net-strangeness and the correlation between net-strangeness with net-baryon and net-charge are sensitive to the quark-hadron phase transition. We have studied the pseudo-rapidity dependence and centrality dependence of mixed-cumulants of net-baryon and net-strangeness correlation, net-baryon and net-charge correlation as well as net-charge and net-strangeness correlation in Au+Au collision with JAM model. We normalize the mixed culmulants in order to compare with theoretical calculations. In addition. we also studied the correlation of different hadron species and their contribution to net-baryon and the net-strangeness, the net-baryon and the net-charge as well as the net-charge and net-strangeness correlations. These models provide a baseline for studying the QCD phase transition signals and critical points in heavy ion collisions.