Coulomb displacement energies and neutron-proton density distributions

We call attention to the fact that an accumulation of recent data concerning rn, the rms radius of neutron density distributions, in neutron-rich nuclei indicate that values of Δr=rn-rp are considerably smaller than those obtained from simple shell-model prescriptions or predicted by common Hartree-Fock calculations. We show that values of Δr consistent with these data can explain the long-standing Coulomb energy problem (Nolen-Schiffer anomaly).