Extraction of the symmetry energy coefficients from the masses differences of isobaric nuclei

Abstract

The nuclear symmetry energy coefficients of finite nuclei are extracted by using the differences between the masses of isobaric nuclei. Based on the masses of more than 2400 nuclei with $A=9-270$, we investigate the model dependence in the extraction of symmetry energy coefficient. We find that the extraction of the symmetry energy coefficients is strongly correlated with the forms of the Coulomb energy and the mass dependence of the symmetry energy coefficient adopted. The values of the extracted symmetry energy coefficients increase by about 2 MeV for heavy nuclei when the Coulomb correction term is involved. We obtain the bulk symmetry energy coefficient $S_0=28.26\pm1.3$ MeV and the surface-to-volume ratio $\kappa=1.26\pm 0.25 $ MeV if assuming the mass dependence of symmetry energy coefficient $a_{\rm sym}(A)=S_0(1-\kappa/A^{1/3})$, and $S_0=32.80\pm1.7$ MeV, $\kappa=2.82\pm0.57$ MeV when $a_{\rm sym}(A)=S_0 (1+\kappa/A^{1/3})^{-1}$ is adopted.