Effect of Isospin Dependence of Nucleon-nucleon Cross Section on Isospin Fractionation Ratio as Increase of Neutron-proton Ratio of Collision System

• 作者: Liu Jianye Guo Wenyun Ren Zhongzhou Zuo Wei Li Xiguo
• 来源期刊: 近代物理研究所和兰州重离子加速器实验室年报：英文版
• 学科: 物理学
• 关键词: 核子碰撞截面 同位旋分馏 同位旋依赖性 碰撞系统 质子 中子 神经网络 重离子碰撞
• 年，卷（期）: 2005,（1）
• 页码范围: 12
• 页数: 1页
• 分类号: O571.6

摘要

<正>Effect of isospin dependence of nucleon-nucleon (N-N) cross sectionσNNiso on the isospin fractionation ratio (n/p)free/(n/p)liq as the increase of neutron-proton ratio of collision system (n/p)sys is investigated in heavy ion collisions. Where the isospin independent N-N cross sectionsσ1noiso andσ2noiso are defined asσnn=σpp =σnp(σ1noiso) andσnn=σpp=(1/2) (σnp+σnn)(σ2noiso) respectively. An empirical density dependent expression of the in-medium N-N cross section is