Evidence for Intermediate Structure Near an Isobaric Analog Resonance

A particular $J={\frac{1}{2}}^{+}$ analog resonance in $^{71}\mathrm{As}$, observed in elastic and inelastic scattering of protons on $^{70}\mathrm{Ge}$, and corresponding to a single $l=0$ state at 2.22-MeV excitation in $^{71}\mathrm{Ge}$, is found to contain significant substructure encompassing many ultimate finestructure levels.