Multistep inelastic processes in the reactionSi28(He3,d)P29leading to bound and unbound states

Abstract

We analyze the stripping reaction $^{28}\mathrm{Si}(^{3}\mathrm{He},d)^{29}\mathrm{P}$ at an incident $^{3}\mathrm{He}$ energy of 35.3 MeV, considering seven residual states. These extend in excitation energy to 4.8 MeV with the highest four being unbound to proton emission and described via complex energy eigenstates. The results of a distorted-wave Born-approximation analysis are rather disappointing. Through a coupled-channel Born approximation analysis, inelastic excitation in both the entrance and exit channels is shown in several cases to be important in accounting for the detailed shape of the angular distributions. Additional data obtained at 20 and 40 MeV are included in the analysis as a check of the optical potentials and spectroscopic amplitudes adopted. The spectroscopic amplitudes used are consistent with results of large-basis shell-model calculations. Good fits to the ($^{3}\mathrm{He},d$) data are obtained in both shape and magnitude, suggesting that the coupled-channel Born approximation should replace the distorted-wave Born approximation in the analysis of experimental data for single-nucleon transfer reactions in this mass region.