中能重离子碰撞过程中同位旋分馏的特征和机制

利用同位旋依赖的QMD模型主要对中能重离子碰撞中同位旋分馏机制和主要特征进行了讨论和分析， 得到了一些有趣的结果， 并建议将同位旋分馏强度作为提取同位旋相关平均场和建立同位旋不对称核物质状态方程的探针. The degree of isospin fractionation is measured by (N/Z)gas / (N/Z)liq，where (N/Z)gas and (N/Z)liq are the saturated neutron proton ratio of nucleon emissions ( gas phase) and that of fragment emitted (liquid phase) in heavy ion collision at intermediate energy. The calculated results by using the isospin dependent quantum molecular dynamics model show that the degree of isospin fractionation is sensitive to the neutron proton ratio of colliding system. In particular， the degree of isospin fractionation sensitively depends on the symmetry potential and weakly on the in medium nucleon nucleon cross section for the neutron rich system. In this case， we propose that the degree of isospin fractionation can be directly compared with the experimental data so that the information about symmetry potential can be obtained.

Properties and Mechanism of Isospin Fractionation in Intermediate Energy Heavy Ion Collisions

The degree of isospin fractionation is measured by (N/Z)_(gas) / (N/Z)_(liq), where (N/Z)_(gas) and (N/Z)__(liq) are the saturated neutron-proton ratio of nucleon emissions ( gas phase) and that of fragment (emitted) (liquid phase) in heavy ion collision at intermediate energy. The calculated results by using the isospin-dependent quantum molecular dynamics model show that the degree of isospin fractionation is sensitive to the neutron-proton ratio of colliding system. In particular, the degree of isospin fractionation sensitively depends on the symmetry potential and weakly on the in-medium nucleon-nucleon cross section for the neutron-rich system. In this case, we propose that the degree of isospin fractionation can be directly compared with the experimental data so that the information about symmetry potential can be obtained.