Effect of the momentum dependence of the nuclear symmetry potential on theπ−/π+ratio in heavy-ion collisions

Abstract

In the framework of the isospin-dependent Boltzmann-Uehling-Uhlenbeck transport model, the effect of the momentum dependence of the nuclear symmetry potential on the ${\ensuremath{\pi}}^{\ensuremath{-}}/{\ensuremath{\pi}}^{+}$ ratio in the neutron-rich reaction $^{132}\mathrm{Sn}$ $+$ $^{124}\mathrm{Sn}$ at a beam energy of $400$ MeV/nucleon is studied. We find that the momentum dependence of the nuclear symmetry potential affects the compressed density of colliding nuclei, the numbers of produced ${\ensuremath{\pi}}^{\ensuremath{-}}$ and ${\ensuremath{\pi}}^{+}$, as well as the value of the ${\ensuremath{\pi}}^{\ensuremath{-}}/{\ensuremath{\pi}}^{+}$ ratio. The momentum-dependent nuclear symmetry potential increases the compressed density of colliding nuclei, the number of produced resonances $\ensuremath{\Delta}(1232)$, ${N}^{*}(1440)$, ${\ensuremath{\pi}}^{\ensuremath{-}}$, and ${\ensuremath{\pi}}^{+}$, as well as the value of the ${\ensuremath{\pi}}^{\ensuremath{-}}/{\ensuremath{\pi}}^{+}$ ratio.