Two-Neutron Stripping Reaction (O18,O16) onCa48

Differential cross sections for ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}$(${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$)${}_{}{}^{50}{}_{}{}^{}\mathrm{Ca}$ have been measured at 50 MeV. The ground-state transition has been analyzed with a two-nucleon transfer, distorted-wave Born-approximation code including finite-range and recoil effects. The calculations underpredict the experimental cross sections by a factor of 5, which is similar to the factor of 4 for ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}(t, p)$. However a large discrepancy is found between the corresponding factors for two-neutron pickup from ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}$.