Two-proton decay from α -cluster states in C 10 and N 11

Two-proton decay from excited states in C10 and N11 has been characterized from an analysis of the 2p+2α and 3p+2α exit channels. Data from four previously published invariant-mass studies associated with inelastic excitation, multinucleon knockout, and neutron pickup reactions have been considered. A rotational band in C10 was identified built on the second 0+ state which has strong α-cluster molecular structure. The members of this band were tentatively identified up to Jπ=4+ and all identified states have a prompt 2p decay branch. The spins of the 0+ and 2+ members were deduced from comparisons of the momentum correlations in their 2p branches to those from known 2p emitters. The 2+ and the tentative 4+ members are both above the α threshold and exhibit large reduced decay widths for α emission. This band exhibits a similar moment of inertia to its analog in the mirror nucleus Be10. Evidence is also presented for a molecular band in N11 built on the second 3/2- state which 2p decays. Tentative members of this band have been assigned up to Jπ=9/2- and their excitation energies also match their likely analogs in the mirror nucleus Be11.