An exactly solvable $\mathfrak{sp}(4)$ algebraic approach extends beyond the traditional isospin-conserving nuclear interaction to bring forward effects of isospin symmetry breaking and isospin mixing resulting from a two-body nuclear interaction that includes proton-neutron (pn) and like-particle isovector pairing correlations plus significant isoscalar pn interactions. The model yields an estimate for the extent to which isobaric analog $0^{+}$ states in light and medium-mass nuclei may mix with one another and reveals possible, but still extremely weak, nonanalog $\beta$-decay transitions.

• Received 23 August 2004

DOI:https://doi.org/10.1103/PhysRevC.72.054302