Nuclear pasta structures and symmetry energy

対称エネルギーと原子核パスタ

Xia, C.-J.*; 丸山 敏毅  ; 安武 伸俊*; 巽 敏隆*; Zhang, Y.-X.*

Xia, C.-J.*; Maruyama, Toshiki; Yasutake, Nobutoshi*; Tatsumi, Toshitaka*; Zhang, Y.-X.*

In the framework of the relativistic mean field model with Thomas-Fermi approximation, we study the structures of low density nuclear matter in a three-dimensional geometry with reflection symmetry. The effect of finite cell size is treated carefully by searching for the optimum cell size. Typical pasta structures (droplet, rod, slab, tube, and bubble) arranged in various crystalline configurations are obtained for both fixed proton fractions and -equilibration. It is found that the properties of droplets/bubbles are similar in body-centered cubic (BCC) and face-centered cubic (FCC) lattices, where the FCC lattice generally becomes more stable than BCC lattice as density increases. For the rod/tube phases, the honeycomb lattice is always more stable than the simple one. By introducing an - cross coupling term, we further examine the pasta structures with a smaller slope of symmetry energy MeV, which predicts larger onset densities for core-crust transition and non spherical nuclei. Such a variation due to the reduction of is expected to have impacts on various properties in neutron stars, supernova dynamics, and binary neutron star mergers.