Analyzing power measurements of (d,He2) reactions on light nuclei

Spin-flip charge-exchange (d, ${}_{}{}^2{}_{}{}^{}\mathrm{He}$) reactions on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$, and ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ were measured at $E_d=70\mathrm{}$ MeV. At forward angles, negative vector analyzing powers of -0.2 to -0.6 were observed for $\Delta L=0\mathrm{}$ transitions for all targets studied, whereas a positive value was obtained for the transition to the 4.4 MeV excited state of ${}_{}{}^{12}{}_{}{}^{}\mathrm{B}$ in the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(d,${}_{}{}^2{}_{}{}^{}\mathrm{He}$) reaction for which $\Delta L=1\mathrm{}$ is the main component. Distorted-wave Born-approximation calculations reproduce this $\Delta L$ dependence of the analyzing power. The fits to the data for $\Delta L=0\mathrm{}$ transitions are improved if the two-step processes via d-p-${}_{}{}^2{}_{}{}^{}\mathrm{He}$ and d-${}_{}{}^3{}_{}{}^{}\mathrm{He}$-${}_{}{}^2{}_{}{}^{}\mathrm{He}$ channels are taken into account.