One-nucleon pickup reactions on 32S: Experimental results and shell-model calculations

The ³²S( d, ³He) ³¹P and ³²S( ³He,α) ³¹S reactions have been investigated at incident energies of E_d = 27 MeV and E_{3 He} = 25 MeV. The experimental values of excitation energies (0 ⩽ E_x(MeV) ⩽ 8) have been compared with the predictions of a complete sd-shell space, shell-model calculation. Spectroscopic factors obtained for 22 levels of ³¹S through the DWBA analysis of the experimental angular distributions have also been compared with the shell-model predictions. In order to reconcile the experimental and shell-model predicted values of the spectroscopic factors, the geometrical parameters of the spin-orbit part of the transferred nucleon potential are required to be smaller than those of the central part as it was previously observed in studies of the one-proton ( ³He, d) stripping reaction. The experimental fragmentation of the 1d _{5}/{2} and 2s _{1}/{2} strengths is correctly reproduced by the shell-model calculations. Twenty pairs of levels were identified as mirror states in the ³¹S and ³¹P nuclei and the ambiguities concerning the J^π-values of eleven ³¹S levels could be removed.