中能重离子碰撞中同位旋相关核子-核子碰撞截面和同位旋相关平均场的探针

在最近几年我们通过使用同位旋相关的量子分子动力学模型（IQMD）系统的研究了同位旋相关的平均场和介质中核子－核子（N－N）碰撞截面对中能重离子碰撞（HIC）中碎裂和耗散的同位旋效应。我们发现原子核阻R和Qzz，中等质量碎片多重性Nimf和质子（中子）发射数Np(Nn）敏感的依赖于介质中N－N碰撞截面的同位旋效应，而弱的依赖于同位旋相关的平均场（对称势），这些物理量作为提取相对高能范围缺中子系统的同位旋相关介质中N－N碰撞截面的探针。我们也可以通过相对低能区到150MeV/u的前平衡核子发射中质比来提取关于对称势的知识和讨论它的同位旋依赖性。

PROBING THE ISOSPIN DEPENDENT IN-MEDIUM NUCLEON-NUCLEON CROSS SECTION AND THE ISOSPIN DEPENDENT MEAN FIELD IN INTERMEDIATE ENERGY HEAVY ION COLLISIONS

In the recent few years we studied systematically the isospin influences of the mean field and the in_medium nucleon_nucleon (NN) cross section on the processes of the fragmentation and dissipation in the intermediate energy heavy ion collisios (HIC) by using an isospin_dependent quantum molecular dynamics model (IQMD). It was found the nuclear stopping R or Qzz, the multiplicity of intermediate mass fragments N imf and the number of proton (neutron) emissions N p N n depend sensitively on the isospin dependence of in_medium NN cross section and weakly on the isospin dependent mean field (symmetry potential) as three probes for extracting the information about the isospin dependence of in_medium NN cross section in relative high energy region for the neutron_deficient systems. Meanwhile we extended the probe for extracting information on the symmetry potential by the neutron_proton ratio of the preequilibriution nucleon emission from the relative low energy region to about 150 MeV/nucleon and discussed its isospin effects. The physical explanations on the isospin effects of above quantities as the probes were discussed more detail. In this paper, based on our studied results combining with the progress in the same project in the world the brief summary of the progress is given and discussed.