Coulomb Displacement Energies and Neutron-Proton Density Distributions

Abstract

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