Visualizing 11N by resonance reactions

The proton-rich, unbound nucleus 11N has been studied using the technique of elastic resonance scattering in inverse geometry. The spins and parities of the three lowest resonance levels have been determined as 1/2+, 1/2− and 5/2+, resulting from the orbitals 1s1/2, 0p1/2 and 0d5/2, respectively. This level ordering is the same as the one found in the mirror nucleus of 11N, namely the one-neutron halo nucleus 11Be. Especially, the in 11Be well known level inversion, where the ground state is a 1/2+ intruder state below the from a naive shell model expected ground state 1/2−, is also found in 11N.