Two-particle Correlation Function With Time-compression Effects

The physics of high energy heavy ion collisions is a new subject in the last century.This subject studies the new nuclear matter phase produced by high energy nucleus-nucleus collisions at relativistic and super-relativistic energies,which helps people to obtain the information of nuclear matter in the experimental process.In the process of high energy heavy ion collision experiment,the high temperature and high density hadron source system can produce mass shift effect through Bogoliubov transformation,which makes free particles become quasi-particles,and a kind of squeezed correlation between positive and negative boson pairs can be produced,which is called squeezed back-to-back correlation.It has been found that in the equilibrium extended source,the particles in the back-to-back correlation of compressed particles and antiparticles will be emitted in a finite time.In Order to study the effect of the emission time on the correlation function,based on the back-to-back correlation function with the mass shift effect and considering the effect of the finite emission time on the back-to-back correlation,two different evolution time factors,Lorentz distribution and Levy distribution,are introduced to act on the two-particle compressed correlation function.The back-to-back correlation function of the boson pair with time compression is obtained.By comparing with the particle emission of instantaneous freezing out,the results show that the influence of different time evolution on the correlation function is very different.Compared with the particle emission of instantaneous freezing out model,the Lorentz distribution and Levy distribution of the evolution time factor are more sensitive to the correlation function.Especially for the Levy distribution model,when the characteristic exponent ? reaches a certain value,the back-to-back correlation is severely suppressed,which may provide necessary information for further study of the back-to-back correlation.