Discovery of a $6^{-}$, $T=1\mathrm{}$ Resonance in ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ via High-Resolution Inelastic Electron Scattering

The unique high-resolution and high-energy features of the electron-scattering facility at the MIT-Bates Accelerator were used to locate a dominant narrow resonance at 15.045 ± 0.035 MeV in ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$. A spin-parity assignment of $6^{-}$ and an isospin $T=1\mathrm{}$ assignment were made. The $M6\mathrm{}$ form factor was measured and compared to the prediction of a theoretical calculation which uses the open-shell random-phase approximation on a shell-model ground state for ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$.