Coupled-Channel-Born-Approximation Analysis of "Allowed" and "Forbidden"Ne22(p,t)Ne20Transitions

The effects of inelastic excitations on the ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}\mathrm{}(p,t)\mathrm{}{}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ reaction are investigated. Differential cross sections at a proton energy of 39.8 MeV were measured for ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}\mathrm{}(p,t)\mathrm{}{}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ transitions to the $0^{+}$, $2^{+}$, and $4^{+}$ members of the ground-state rotational band, to the $2^{-}$ and $3^{-}$ members of the excited $K^{\pi }=2^{-}$ band; and to the $0^{+}$ and $2^{+}$ members of the first excited $K^{\pi }=0^{+}$ band. The cross sections to members of the ground-state band are compared with distorted-wave Born-approximation (DWBA) and coupled-channel-Born-approximation (CCBA) calculations using both pure Nilsson and pairing-mixed Nilsson rotational wave functions. Only the CCBA calculation with pairing provides a reasonable description of the experimental data. The effects of multistep processes are found to be as large for neon as for rareearth nuclei. The shape and relative strength of the measured cross section to the $2^{-}$ state, a transition which is forbidden by a direct single-step process, are reproduced well by the CCBA calculation, which allows the excitation of the $2^{-}$ state by inelastic processes in the entrance and exit channels.