Spectroscopy of N 10 with the invariant-mass method

Proton decays of N10 states have been investigated with the invariant-mass technique using data from two reactions. In the first experiment, N10 states were created via multinucleon knockout from a fast O13 beam. The second experiment involved proton pickup from a Be9 target to a fast C9 beam. Both data sets produce similar distributions with a peak centered at a decay energy of 2.8 MeV and a width of ≈2.5 MeV. This result is consistent with a previous study using a multinucleon transfer reaction which was originally fit with an ℓ=0 resonance but later interpreted as an ℓ=1 resonance. This later interpretation is affirmed as the proton pickup reaction should favor ℓ=1. This strength is located near the predicted energies of two ℓ=1 resonances in calculations using complex scaling and the Gamow shell model. The multinucleon knockout data also show excess strength below the main peak which is interpreted as contributions from one or more ℓ=0 resonances.