On the charge-asymmetric term in the nuclear binding energies of heavy nuclei

The charge-asymmetric term Esub(a)(N-Z) in the volume part of the nuclear binding energy of heavy nuclei is estimated using Brueckner theory and the variational approach. Calculations are performed using phenomenological charge-symmetry-breaking nuclear interactions, which are consistent with Coulomb displacement energies in mirror nuclei. The results obtained using standard Brueckner theory are very close to those obtained in the variational approach with realistic state-dependent correlation functions. An estimate Esub(a) approximately equals -0.6 MeV is obtained, in good agreement with semi-empirical estimates of this quantity. (author)