Exploring the neutron-star matter properties via the deformed nuclear reactions

Abstract

Within the framework of Lanzhou quantum molecular dynamics transport model, the correlation of initial deformation and isospin diffusion is systematically investigated in collisions of ${}^{238}$U + ${}^{238}$U. The impacts of the collision centrality, symmetry energy and initial configuration on the collective flows, neutron/proton and ${\pi }^{-}/{\pi }^{+}$ ratios have been systematically investigated. It is found that the broader neutron-rich region is formed in the body-body collisions in comparison with the ones in the tip-tip collisions. The neutron-star matter might be created in the density region of 0.2-0.5 ${\rho }_0$ (the normal nuclear density ${\rho }_0$=0.165 fm${}^{-3}$) formed in the ${}^{238}$U + ${}^{238}$U reaction at the incident energy of 500 MeV/nucleon. The elliptic flows of protons are related to the incident energy, collision centrality, symmetry energy and collision orientation. The hard symmetry energy enables the larger free neutron/proton ratio at the beam energy of 500 MeV/nucleon. However, the neutron/proton and ${\pi }^{-}/{\pi }^{+}$ ratios in the density regime of $1.2\le \rho /{\rho }_0\le 1.8$ are enhanced by the soft symmetry energy with the slope parameter of L=42 MeV.

Comments: 7 pages, 7 figures