高能碰撞J/ψ粒子的产生与能量损失效应

Nuclear energy loss effect and the production of J/ψ at high energy collisions

根据色蒸发产生机制、应用能量损失的上限值计算了RHIC和HERA上J/ψ粒子产生中核效应α的xF分布,并与实验数据进行了对比.研究表明:给定初态能量损失上限,较之HERA的结论,RHIC的计算与实验吻合更好,反映出后者的末态效应较弱.加入末态效应后均有所改观,表明解释J/ψ粒子产值的抑制还需要考虑其它的介质效应.

In this paper we calculated the nuclear effect parameter α（xF） in production of J/Ψ with Color Evaporate Model.The plots of α（xF） vs.xF calculated with strict upper limits of energy loss under RHIC and HERA energy were presented.By a comparison with the experimental data,we found that the result calculated under RHIC energy is much better in agreement with data than that of HERA,which indicated that the finalstate effect in HERA is stronger than that in RHIC.Compared with the results including final-state effect we draw a conclusion that some other mechanisms should be responsible for the ＂nomal nuclear absorption＂ of J/Ψ production in high energy collisions.