Analysis Of HBT Intensity Interferometry For Gaussian And Nongaussian Source

In the high-energy nuclear physics, we use particle intensity interferometrymethod to detect the scale of the emission source, spatial distribution, and evolution.And the spatial location, scale information of the Source, most include in the sourcefunction. The kernel of the problem in interferometry is, to calculate and fit thecorrelation function to obtain the source function of the emission source. Correlationfunction affected by many factors, such as, the collective expansion of the source,the resonance state decay, the distribution of the source. To obtain the sourcefunction from the correlation function, you need to know the type of distribution,while it actually cannot be known. People now assume that use Gauss function forthe fitting function of the correlation function. While in the experiment, the realdistribution of the source is not completely Gauss function, and is impacted by th eexpansion of the source, and the resonance states decay. In this paper, we discuss theinfluence of the Gaussian tpye on the HBT radius, in the sight of the differencebetween the calculated HBT radius and Gaussian fitting correlation function to getthe HBT radius. The theory and experiment show that, the calculated HBT radius isthe same as the HBT radius from Gaussian fitting correlation function, when thecorrelation function of two particles is the Gaussian tpye. As the HBT radius, whichdirectly extrated from calculation, will be not impacted by the Gaussian type of thesource, that can be as the standard of HBT radius. So the difference, between theHBT radius extrated form calculation and Gassian fiting correlation function of thesame source, can be as the dependence of the influence on the HBT radius of theGaussian tpye of the source. The influence of Gaussian tpye of the source on theHBT radius can be discussed by the collective expansion, and this is the part reasonof the influence. In this paper, we compare with the HBT radius from the twomethods for static Gaussian source, well-distribution source and shell source, plusthe expansion Gaussian source, well-distribution source and shell source. Finally,compare the differernce between directly extracted HBT radius from calculation andGaussian fitting obtaining the HBT radius, to analysis the influence of the Gaussiantype.