【摘要】 利用同位旋相关的量子分子动力学模型 ,研究了12 4 Ba +12 4 Ba和12 4 Sn+12 4 Sn两个系统在不同入射能量下对心碰撞的径向膨胀流 .发现丰中子系统12 4 Sn +12 4 Sn的径向膨胀流系统性地小于系统12 4 Ba +12 4 Ba的径向膨胀流 .同时发现这种差别主要来自于核子 -核子碰撞截面的同位旋相关性而几乎与对称能无关更多还原

【Abstract】 Within the framework of an isospin dependent quantum molecular dynamics model which includes isospin dependent symmetry energy, Coulomb energy, nucleon nucleon cross sections, Pauli blocking, and initialization, we have shown that there is a strong isospin dependence of the radial expansion flow from the symmetric central collisions at incident energies of a few hundred MeV per nucleon. It is found that the more neutron rich system exhibits smaller radial expansion flow, which is shown to result from the isospin dependence of nucleon nucleon cross sections and to be independent of the nuclear symmetry energy. It suggests that the experimental measurement of the radial expansion flow for reaction systems with different ratios of neutron to proton provide a novel method for determining the isospin dependent in medium nucleon nucleon cross sections.更多还原