Mirror energy differences of $2s_{1/2}$ single-particle states: Masses of ${}^{10}$N and ${}^{13}$F

I have examined mirror energy differences between 2$s_{1/2}$ states in neutron-excess nuclei with $N$ $=$ 7 and 9 and their proton-excess mirrors having $Z$ $=$ 7 and 9. I find they can be fitted by a simple expression, which I then use to predict the masses of ${}^{10}$N and ${}^{13}$F.

Figure 1

Plot of Diff′ (see text) vs neutron separation energy with linear (light) and quadratic (heavy) fits.

Figure 2

Difference between calculated and experimental proton separation energies. The solid curve is for the linear fit, and the dashed curve is for the quadratic fit of Fig. 1.