Two-pion Interferometry For (1+1) And (2+1)d Hydrodynamic Sources

In physics of heavy-ion-collision， how to describe the souce of hightemperature and high density which formed in the high-energy heavy-ioncollisions is a challenging problem. To solve this problem,people accumulatedexperimental data analysis, it was found that the HBT radius of a downwardtrend with increasing transverse momentum. Source of high energy heavy ioncollisions is similar to the fluid evolution trend. So to some extent, thehydrodynamic model can be more reasonable to describe the evolution of thesource.As we know the basic equations to describe the hydrodynamicsevolution and introduce a basic algorithm numerical solution of theseequations. First, we use a (1+1)D spherically symmetric hydrodynamic modelto generate some particles, then analyze the information carried by theseparticles. The HBT radius changes with the transverse momentum. Because wewant to know more detail of this souce,so we use this (1+1)D hydrodynamicsmodel to produce more information in different initial temperatureconditions.Then we get more information of these generated particles. The2π interferometry analysis is obtained by fitting the one-dimensional andthree-dimensional situation, to find the change of the HBT radius as thedifferent initial temperature.Then we consider more about this (1+1)Dmodel,if the evolution of source has two different direction, use some basicnumerical soltions,change this (1+1)D model into2+1D hydrodynamicmodel.This (2+1)D model has two directions that along z-direction andtransverse direction. In this (2+1)D model,we can find in different initialconditions HBT radius change with the transverse momentum. And under thesame the initial temperature, we can find the HBT radius different results of(1+1)D and (2+1)D model.