The Density-Dependence Of Symmetry Energy For Nuclear Matter Around Saturation Density

The equation of state （EOS） of nuclear matter, especially the nuclear symmetry energy which describes the isospin-dependent part of the EOS, is a key quantity in nuclear physics. Nuclear symmetry energy plays a crucial role in plenty of issues in nuclear physics, heavy ion physics and nuclear astrophysics. This dissertation has focused on investigating the density dependence of symmetry energy around the satu-ration density.A new approach has been proposed to constrain the density dependence of nu-clear symmetry energy around the saturation density, by using the mass difference of heavy nuclei. Based on the proposed scheme, the mass-dependent symmetry energy coefficient αsym（A） of finite nuclei has been extracted, and the density dependence of symmetry energy of nuclear matter around the saturation density is predicted. The obtained slope parameter is L= （50.0+15.5） MeV.Based on our above-obtained results, we also have studied the density behavior of symmetry energy around the sub-saturation density p= 0.11fm-3 by making use of the nucleon density profile. The symmetry energy and its slope parameter at p= 0.11fm^-3 are estimated to be S*₀.11= （24.8-26.3） MeV and L*₀.11= （40.5-60.3） MeV, respectively. It is shown that there exists a linear relation between the slope parameter L₀.11, calculated directly with Skyrme interactions for nuclear matter, and the neutron skin thickness △R_np of 208Pb. According to this linear relation, the neutron skin thickness △R_np of ²08Pb is predicted to be （0.15-0.21） fm, which turns out to be too small to allow the direct URCA process in the 1.4M☉ neutron stars.