Sn120 homologous levels via the 123Sb(p→,a)Sn120 reaction: Experimental evidence and microscopic calculations

The Sb123(pâ†,α)Sn120 reaction has been studied in a high resolution measurement at incident energy of 24 MeV using a polarized proton source and a Q3D spectrometer. The differential cross sections and asymmetries for transitions to levels of Sn120 homologous to the lowest energy states of In119 have been measured and interpreted in terms of the experimental differential cross sections and asymmetries of the parent In119 states, on the basis of the weak-coupling model. Several (17) states of the Sn120 residual nucleus, not previously reported in the literature, have been detected and spins and parities have been proposed for seven of them, while parities have been proposed for five other previously known levels. In order to analyze the transitions populating the homologous levels, for both differential cross sections and asymmetries, microscopic DWBA calculations have been performed using spectroscopic amplitudes obtained from a shell-model study.