Isospin Dependence of Nucleon-Nucleon Elastic Cross Section

Abstract

The in-medium neutron-proton, proton-proton(neutron-neutron) scattering cross sections(${\sigma }_{np}^{\ast }$, ${\sigma }_{pp(nn)}^{\ast }$) are studied based on QHD-II type Lagrangian within the framework of the microscopic transport theory. The results demonstrate that, for free nucleon-nucleon scattering cross sections, the isospin dependence is dominantly caused by $\rho$ meson field. The medium correction of nucleon-nucleon scattering cross sections is also isospin dependent, ${\sigma }_{np}^{\ast }$ depends on the baryon density weakly and ${\sigma }_{pp(nn)}^{\ast }$ depends on the baryon density significantly, which is due to the different effects of the medium correction of nucleon mass and $\rho$ meson mass on ${\sigma }_{np}$ and ${\sigma }_{pp(nn)}$, respectively

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