Isobaric Mass Quartets in the Mass-21 and Mass-37 Nuclei

The ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$(${}_{}{}^3{}_{}{}^{}\mathrm{He}$, ${}_{}{}^6{}_{}{}^{}\mathrm{He}$)${}_{}{}^{37}{}_{}{}^{}\mathrm{Ca}$ reaction has been used to measure the mass of ${}_{}{}^{37}{}_{}{}^{}\mathrm{Ca}$ in its ground and first excited states. The mass of ${}_{}{}^{37}{}_{}{}^{}\mathrm{Ar}$ and ${}_{}{}^{37}{}_{}{}^{}\mathrm{K}$ in their lowest $T=\frac{3}{2}$ states was also measured. The ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$(${}_{}{}^3{}_{}{}^{}\mathrm{He}$, ${}_{}{}^6{}_{}{}^{}\mathrm{He}$)${}_{}{}^{21}{}_{}{}^{}\mathrm{Mg}$ reaction was used as a calibration, and consequently the energies of several excited states of ${}_{}{}^{21}{}_{}{}^{}\mathrm{Mg}$ were measured. The mass-37 measurements give new precision values for the coefficients of the isobaric multiplet mass equation, and the excited states in ${}_{}{}^{21}{}_{}{}^{}\mathrm{Mg}$ are members of quartets in the mass-21 nuclei.