Isospin dependence of the saturation properties of asymmetric nuclear matter in nonrelativistic mean field model

A phenomenological momentum dependent interaction (MDI) is considered to describe the equation of state (EOS) for isospin asymmetric nuclear matter (ANM), where the density dependence of the nuclear symmetry is the basic input. In this interaction, the symmetry energy shows soft dependence of density. Within the nonrelativistic mean field approach we calculate the nuclear matter fourth-order symmetry energy Esym,4(ρ). Our result shows that the value of Esym,4(ρ) at normal nuclear matter density ρ0( = 0.161 fm-3) is less than 1 MeV conforming the empirical parabolic approximation to the EOS of ANM at ρ0. Then the higher-order effects of the isospin asymmetry on the saturation density ρsat(β), binding energy per nucleon Ksat(β) and isobaric incompressibility Ksat(β) of ANM is being studied, where β = [ρn - ρp]/ρ is the isospin asymmetry. We have found that the fourth-order isospin asymmetry β cannot be neglected, while calculating these quantities. Hence the second-order Ksat,2 parameter basically characterizes the isospin dependence of the incompressibility of ANM at saturation density. (author)