Neutron occupancy of the 0d5/2 orbital and the N=16 shell closure in 24O

One-neutron knockout from O-24 leading to the first excited state in O-23 has been measured for a proton target at a beam energy of 62 MeV/nucleon. The decay energy spectrum of the neutron unbound state of O-23 was reconstructed from the measured four momenta of the O-22 fragment and emitted neutron. A sharp peak was found at E-decay = 50 +/- 3 keV, corresponding to an excited state in O-23 at 2.78 +/- 0.11 MeV, as observed in previous measurements. The longitudinal momentum distribution for this state was consistent with d-wave neutron knockout, providing support for a J(pi) assignment of 5/2(+). The associated spectroscopic factor was deduced to be C-2 S(0d(5/2)) = 4.1 +/- 0.4 by comparing the measured cross section (sigma(exp)(-1n) = 61 +/- 6 mb) with a distorted wave impulse approximation calculation. Such a large occupancy for the neutron 0d(5/2) orbital is in line with the N = 16 shell closure in O-24. (C) 2014 The Authors. Published by Elsevier B.V.