Particle-decaying states of the light nuclei N-11,N-12 and O-12 were studied using the invariant-mass method. The decay energies and intrinsic widths of a number of states were measured, and the momentum correlations of three-body decaying states were considered. A second 2p-decaying 2(+) state of O-12 was observed for the first time, and a higher-energy O-12 state was observed in the 4p + 2 alpha decay channel. This 4p + 2 alpha channel also contains contributions from fissionlike decay paths, including Be-6(g.s.) + Be-6(g.s.). Analogs to these states in O-12 were found in N-12 in the 2p + B-10 and 2p + alpha + Li-6 channels. The momentum correlations for the prompt 2p decay of O-12(g.s.) were found to be nearly identical to those of Ne-16(g.s.), and the correlations for the new 2(+) state were found to be consistent with sequential decay through excited states in N-11. The momentum correlations for the 2(1)(+) state in O-12 provide a new value for the N-11 ground-state energy. The states in N-12/O-12 that belong to the A = 12 isobaric sextet do not deviate from the quadratic isobaric multiplet mass equation form.
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