同位旋相关的核子碰撞截面的不同形式与核子的集体流

Isospin-dependent nucleon-nucleon cross section and the collective flow of nucleons in heavy-ion collision at intermediate energy

在详细比较同位旋相关的核子-核子碰撞截面的几种常用形式的基础上,利用IBUU模型,分别对具有相同质量的^(60)Ca+^(60)Ca和^(60)Ni+^(60)Ni的中能重离子碰撞进行了模拟计算,定量地分析了碰撞过程中不同形式的同位旋相关的核子-核子碰撞截面对于核子的快度分布和集体流的影响,结果显示:不同形式的核子碰撞截面,可以给出相差较大的核子的快度分布和横向流,但在同一种截面形式下,对称势的变化对横向流的影响较小,这表明在新的动量相关的对称势下,中能重离子碰撞中集体流对于截面的敏感性依然成立;同时表明,在相同的碰撞截面和对称势形式下,当入射能量在平衡能附近时,入射粒子的中质比对核子在平面流的影响较大,反之,影响较小.

In this paper,the influences of the different forms of nucleon-nucleon（NN） cross sections on the rapidity distributions and the in-plane flows of nucleons in reactions ^（60）Ca＋^（60）Ca and ^（60）Ni＋^（80）Ni are studied by using IBUU04 transport model with the momentdependent symmetry potential.The calculation results indicate that（1） the discrepancies of the rapidity distributions and in-plane flows corresponding to different forms of NN cross sections are large,（2） the sensitivity of the in-plane flow to the NN cross section still holds when the new form of moment-dependent symmetry energy is adopted,and（3） the influence of the N/P ratio of reaction systems on the transverse flow calculated with a certain NN cross section is more obvious when the incident energy is near the balance energy.