Higher order bulk characteristic parameters of asymmetric nuclear matter

Abstract

The bulk parameters characterizing the energy of symmetric nuclear matter and the symmetry energy defined at normal nuclear density $ρ_0 $ provide important information on the equation of state (EOS) of isospin asymmetric nuclear matter. While significant progress has been made in determining some lower order bulk characteristic parameters, such as the energy $E_0(ρ_0)$ and incompressibility $K_0$ of symmetric nuclear matter as well as the symmetry energy $E_{sym}(ρ_0)$ and its slope parameter $L$, yet the higher order bulk characteristic parameters are still poorly known. Here, we analyze the correlations between the lower and higher order bulk characteristic parameters within the framework of Skyrme Hartree-Fock energy density functional and then estimate the values of some higher order bulk characteristic parameters. In particular, we obtain $J_0=-355 \pm 95$ MeV and $I_0=1473 \pm 680$ MeV for the third-order and fourth-order derivative parameters of symmetric nuclear matter at $ρ_0 $ and $K_{sym} = -100 \pm 165$ MeV, $J_{sym} = 224 \pm 385$ MeV, $I_{sym} = -1309 \pm 2025$ MeV for the curvature parameter, third-order and fourth-order derivative parameters of the symmetry energy at $ρ_0 $, using the empirical constraints on $E_0(ρ_0)$, $K_0$, $E_{sym}(ρ_0)$, $L$, and the isoscalar and isovector nucleon effective masses. Furthermore, our results indicate that the three parameters $E_0(ρ_0)$, $K_0$, and $J_0$ can reasonably characterize the EOS of symmetric nuclear matter up to $2ρ_0 $ while the symmetry energy up to $2ρ_0 $ can be well described by $E_{sym}(ρ_0)$, $L$, and $K_{sym}$.