Exclusive quasi-free proton knockout from oxygen isotopes at intermediate energies

The dependence of the single-particle strength on the difference between proton and neutron separation energies is studied for oxygen isotopes in a wide range of isospins. The cross sections of the quasi-free (p, 2p) reaction on O-14,O-16,O-18,O-22,O-24 were measured at intermediate energies. The measured cross sections are compared to predictions based on the distorted wave impulse approximation and shell-model psd valence-space spectroscopic factors. The reduction factors, which are the ratio of the experimental cross sections to the theoretical predictions, show no apparent dependence on the proton-neutron separation energy difference. The result is compatible with the result of the (e, e'p) reaction on stable targets and with the predictions of recent ab initio calculations.