利用imaging方法提取高能重离子碰撞中Core-Halo模型发射源的信息

Extracting Information of Core Halo Model in Heavy ion Collisions by Imaging Technique

摘要: 根据对高斯源的检验，引入两个π介子相对距离的均方根半径R_rmst来表示高能重离子碰撞中π介子发射源的空间尺寸。利用imaging计算方法可以不依赖于源模型计算出相对距离的均方根半径。对Core-Halo模型进行计算并与高斯拟合结果比较，结果显示，由于长寿命共振态衰变产生的π介子的贡献，半径R_rmst显示出较大的π介子发射空间。另外，对于π介子为混沌发射的情况，通过imaging方法计算得到的π介子发射源的混沌性参量明显大于高斯拟合所得到的结果。

Abstract: We characterize the spatial dimension of pionemitting source in highenergy heavy ion collisions with the radius of rootmeansquared of twopion relativedistance R_rmst. Based on the imaging technique， one can calculate R_rmst modelindependently. Applying this method to the Core-Halo model and comparing the results with that of Gaussian fitted， the results indicate that due to the effects of longlived resonance decay， the values of R_rmst show a larger spatial size of pionemitting region. Meanwhile， for the chaotic source the chaoticity factors calculated by imaging technique are larger than that of Gaussian fitted.