Study of the unbound nucleus N-11 by elastic resonance scattering

Resonances in the unbound nucleus N-11 have been studied, using the resonance scattering reaction C-10+p. The data give evidence for three states above the C-10+p threshold with energies 1.30, 2.04, and 3.72 MeV. These states can be interpreted, in a potential-model analysis, as the ground state and the first two excited states with spin-parity 1/2(+), 1/2(-), and 5/2(+) arising from the shell-model orbitals 1s(1/2), Op(1/2), and Od(5/2). A narrow state superposed on a broad structure found at higher energy could be interpreted as the mirror state of the 3/2(-) in Be-11 shifted down in energy. This shift would suggest a large radius of the potential.