Constraints on Coulomb energy, neutron skin thickness in Pb-208, and symmetry energy

摘要

The charge-symmetry-breaking (CSB) effect in a nuclear medium that gives rise to the first-order symmetry energy in finite nuclei is discussed in detail in the present paper. For heavy and superheavy nuclei with large neutron excesses, it should be nonnegligible in high-precision mass predictions, and importantly it affects the stability of these nuclei. Combined with this CSB effect, the Coulomb energy is constrained by using the experimental Coulomb displacement energy of mirror nuclei, and then the mass-dependent symmetry energy coefficients of heavy nuclei are reextracted with the experimental beta(-)-decay energies of heavy odd-A nuclei and with the experimental mass differences. Based on these results, we probe the neutron skin thickness Delta R-np of Pb-208 and the density-dependent symmetry energy coefficient of nuclear matter. Delta R-np in Pb-208 is found to be 0.158 +/- 0.014 fm, and the slopes L of the symmetry energy coefficient at densities of rho = 0.16 and rho = 0.11 fm(-3) are estimated to be 42 +/- 8 and 42 +/- 3 MeV, respectively. These results would be meaningful to discriminate between the models and the predictions that are relevant for the investigations on properties of nuclei and of neutron stars.