Fragmentation Of Gamow-Teller Strength Observed In Sn-117,Sn-120(He-3,T)Sb-117,Sb-120 Charge-Exchange Reactions

The (He-3,t) charge-exchange reaction has been studied at E(He-3) = 200 MeV and angles near 0-degrees on targets of Sn-117 and Sn-120. Fragmentation of the giant Gamow-Teller resonance into separate components of the particle-hole type has been observed in good agreement with theoretical predictions. These components are connected with what is usually referred to in the literature as direct-, core-polarization-, and back-spin-flip Gamow-Teller strength. The observed cross sections near theta = 0-degrees suggest contributions from the isovector spin-flip interaction as well as the isovector tensor interaction. A theoretically predicted configuration splitting of the main Gamow-Teller component into two components involving the 1h11/2 neutron orbital could not uniquely be identified. The data are compatible, though, with such a splitting since the observed widths of the main Gamow-Teller components in Sb-117 and Sb-120 exceed the predicted splittings.