中能重离子碰撞中的中子(质子)发射的同位旋效应

利用同位旋相关的量子分子动力学,对中能重离子碰撞过程中的中子和质子发射的同位旋效应进行了分析.计算结果表明在有动量相关作用条件下,在很宽的能量和碰撞参数范围内,缺中子碰撞系统的中子(质子)发射数强烈地依赖于同位旋相关的核子–核子碰撞截面,而较弱地依赖于对称势.在对丰中子碰撞系统的研究中,上述规律减弱.这样就可以通过实验上对缺中子碰撞系统的中子(质子)发射数的探测,来提取介质中同位旋相关核子–核子碰撞截面的知识.

Isospin Effect of Neutron (Proton) Emission Number in Intermediate Energy Heavy Ion Collisions

Effects of the symmetry potential U sym and the isospin dependence of in-medium nucleon-nucleon cross section N n( N p) on the number of neutron (proton) emitted as well as their dependence on the momentum dependent interaction (MDI) are studied within an isospin dependent Quantum Molecular Dynamics (IQMD) model. The isospin dependence nucleon-nucleon cross section is found to have a much stronger influence on the N n( N P) especially for the neutron-deficient collision system with MDI in the energy region from about 100 to 400MeV/nucleon. The calculation results are clear to show that the number of neutron (proton) emitted during reaction in the neutron-deficient system,depends sensitively on the isospin dependence of in-medium nucleon-nucleon cross section and weakly on the symmetry potential with MDI. In this case one can make use of the number of neutron (proton) emitted as a probe to extract simultaneously both the magnitude and the in-medium nucleon-nucleon cross section. = =