Two-Nucleon-Transfer Reactions Induced by Polarized Protons

The ($p,t$) and ($p$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}$) reactions on ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ and ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$ targets have been studied using 43.8-MeV polarized protons. The observed cross sections and asymmetries for most states are well reproduced by distorted-wave Born-approximation calculations. However, of the five $L=2\mathrm{}$ ($S=0\mathrm{}$) transitions observed, two exhibit asymmetries which disagree markedly with the other three and with distorted-wave Born-approximation predictions. Thus asymmetries in two-nucleon-transfer reactions do not always appear to be simply characteristic of the transferred quantum numbers.