Spin and isospin modes

Abstract

Sum rule, especially the energy-weighted sum rule (EWSR) of the spin-dipole transition strength is discussed, and the effects of the spin-orbit interaction as well as the kinetic energy term and the tensor interaction on the splitting and distribution of the strength are investigated. Light nuclei such as 12C and 16O are studied by shell-model calculations including up to 3ħω space while HF+TDA is used for an analysis of 208Bi. An application to neutral current neutrino scattering on 16O from supernovae heavy-flavor neutrinos is presented. For the Gamow-Teller mode, effects of quenching and fragmentation of the strength by coupling to 2p-2h configurations are shown to be important. How large or small is the quenching of the strength due to the Δþ contributions is also studied. As an isospin mode, isospin dependence of the spreading width of the isobaric analog state is analyzed and recent experimental data is shown to be well explained.