Investigations of multi-particle exit channels of levels in light nuclei

The HiRA array was used to study the many-particle exit channels produced from the interactions of an $E/A$ = 70 MeV $^{9}$C beam with a $^{9}$Be target. Correlations between these particles were studied to analyze the decays, particularly whether they occur in one prompt step or sequentially through long-lived intermediates. The five-body decay of $^{8}$C is found to occur in two steps of two proton decay through a $^{6}$Be ground-state. In the first step, the correlations between the protons clearly show the enhanced diproton character of the decay, and the second step was found to be consistent with the independently measured $^{6}$Be two-proton decay. A new mass and uncertainty for $^{8}$C were deduced from these data and used in a refit of the A = 8 data to the isobaric multiplet mass equation (IMME). The fit indicates the need for terms beyond quadratic meaning that isospin symmetry is clearly broken for the A = 8 multiplet.