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

Abstract The 32 S( d , 3 He) 31 P and 32 S ( 3 He ,α) 31 S 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 31 S 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 ( 3 He, 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 31 S and 31 P nuclei and the ambiguities concerning the J π -values of eleven 31 S levels could be removed.