New aspects of spin degrees of freedom in nuclei Original Research Article

New aspects of quenching effects in Gamow-Teller (GT) transitions and magnetic moments are investigated for p-shell nuclei using an improved shell-model Hamiltonian with enhanced spin-flip neutron-proton interaction and modified single-particle energies. Here, the improved shell model Hamiltonian is used in the configuration space up to 2–3 ħw excitations to study spin dependent transitions. Manifestation of less quenching due to a weakening of intermediate coupling nature of the Cohen-Kurath Hamiltonian is shown in GT transitions; 12C → 12N, 11B → 11Be and 9Li → 9Be. Better agreement with experimental values is obtained by using the present Hamiltonian in most of GT transitions and magnetic moments in p-shell nuclei.