Identification of the Lowest $T=2$, $J^{\pi=}0^+$ Isobaric Analog State   in $^{52}$Co and Its Impact on the Understanding of $\beta$-Decay Properties   of $^{52}$Ni
  Masses of $^{52g,52m}$Co were measured for the first time with an accuracy of $\sim 10$ keV, an unprecedented precision reached for short-lived nuclei in the isochronous mass spectrometry. Combining our results with the previous $\beta$-$\gamma$ measurements of $^{52}$Ni, the $T=2$, $J^{\pi}=0^+$ isobaric analog state (IAS) in $^{52}$Co was newly assigned, questioning the conventional identification of IASs from the $\beta$-delayed proton emissions. Using our energy of the IAS in $^{52}$Co, the masses of the $T=2$ multiplet fit well into the Isobaric Multiplet Mass Equation. We find that the IAS in $^{52}$Co decays predominantly via $\gamma$ transitions while the proton emission is negligibly small. According to our large-scale shell model calculations, this phenomenon has been interpreted to be due to very low isospin mixing in the IAS. 
X. Xu, P. Zhang, P. Shuai, R. J. Chen, X. L. Yan, Y. H. Zhang, M.   Wang, Yu. A. Litvinov, H. S. Xu, T. Bao, X. C. Chen, H. ...
nucl-ex