Proton decay of states in 11N

The proton-unbound nucleus N-11 has been studied via kinematic reconstruction of the emitted proton in coincidence with the residual C-10 daughter nucleus. Resonances in N-11 were populated by using a 40 MeV/ nucleon radioactive beam of N-12 to induce the reaction Be-9/(N-12,N-11), followed by the proton decay of N-11. The decay energy spectrum was constructed from the energies and separation angle of the C-10 and the proton. In addition to protons from the known 1/2(-) state, at 2.24 MeV above the proton decay threshold, another peak is seen near 1.45 MeV. This peak could potentially be due to the predicted 1/2(+) ground state and/or due to the decay of the 3/2(-) state to the first excited state of C-10.