高能Au+Au、Pb+Pb和In+In碰撞产生的大不变质量双轻子

Large invariant mass dilepton production from high energy Au+Au, Pb+Pb and In+In collisions

摘要: 利用部分子模型，计算了高能重离子碰撞的大不变质量双轻子产生. 分析了双轻子产生的Drell−Yan过程的领头阶贡献和次领头阶（夸克−胶子康普顿散射、夸克−反夸克湮灭过程）贡献. 数值计算结果能够较好地解释RHIC能区Au+Au 200A GeV碰撞和SPS能区Pb+Pb、In+In 158A GeV碰撞产生的大不变质量双轻子实验结果，验证了Drell−Yan过程在不变质量M>4 GeV区域的主导作用.

Abstract: The large invariant mass dilepton produced from the high energy heavy ion collisions is calculated by using the parton modle. The leading order contribution and the next−to−leading order contribution (Compton, quark anti−quark annihilation) of Drell−Yan processes are analysed. The numerical results can explain the large invariant mass data from the Au+Au 200A GeV collisions at RHIC energies and Pb+Pb, In+In 158A GeV collisions at SPS energies. The results verify the leading role of the Drell−Yan process in the region of M>4 GeV.