同位旋依赖的动量相关作用对同位旋分馏过程的影响和机理

The isospin effect of momentum-dependent interaction in heavy ion collisions

在同位旋相关的量子分子动力学理论的基础上,引入同位旋自由度,将同位旋无关的动量相关作用改造成为在同位旋相关的量子分子动力学中可用的同位旋依赖的动量相关作用.研究了它在中能重离子碰撞中的作用和机理.研究结果表明,考虑同位旋依赖的动量相关作用后,对同位旋分馏过程有很大的影响,使同位旋分馏强度降低.降低的幅度随入射能量的增加而迅速增加.特别是动量相关作用的同位旋效应与对称势的同位旋效应具有大体相同数量级.但两者具有完全不同的动力学机理.所以同位旋依赖的动量相关作用的研究对于定量的研究同位旋非对称核物质状态方程是重要的.

We introduce the isospin degree of freedom into the momentum-dependent interaction to obtain an isospin and momentum dependent interaction given in a form practically usable in isospin-dependent quantum molecular dynamics model. We investigate the isospin effect of momentum-dependent interaction on the observable in the intermediate-energy heavy ion collisions. It is found that momentum-dependent interactions with and without isospin dependence, lead to significant different predictions on the nuclear stopping ( momentum dissipation) and isospin fractionation ratio. In particular, the momentum-dependent interaction with the isospin degree of freedom induces the reduction for the strong dependence of isospin fractionation ratio on the symmetric potential. However, it does not change obviously the above feature for the isospin fractionation ratio as the good probe of symmetric potential respectively. The isospin dependence of momentum-dependent interaction is thus important for studying accurately the equation of state of isospin asymmetry nuclear matter.