Theoretical Study of M1 and Gamow-Teller Transitions in Nuclei

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1. Effects of halo on the retardation of the Gamow - Teller (GT) beta transition from ^<11>Li as well as on the Coulomb displacement energy of the isobaric analog state (lAS) of ^<11>Li are investigated. The structure of the two-neutron halo state in ^<11>Li is determined.2. Spreading and quenching of the GT strength in ^<90>Zr and ^<208>Pb are found to be mainly caused by the coupling to the 2p - 2h configurations. Observed GT strengths are well reproduced by our calculations.3. Sum rule for the Ml transitions between GT and lAS is derived, which is found to be extremely enhanced compared to the sum rule for the parent nucleus. The effects in ^<11>Li, in particular, are investigated.4. Spreading effects due to the tensor interaction in spin-dipole transition strengths are investigated. Sum rules for the E1 transitions between the GT and spin-dipole states are derived for various configuration spaces.5. Relation between the spreading width of the IAS and the isospin mixing in the parent state is obtained. New formula for the isospin dependence of the spreading width is derived and applied to the recent observations, which prove to be quite successful.6. Importance of the effects of the halo in "Be is pointed out for the muon capture rate in ^<11>B as well as for the hyperfine anomaly in Be isotopes.7. Effects of K and PI meson exchange currents on magnetic moments of hypernuclei are studied. Structure of pigmy E1 resonances in neutron-rich nuclei, ^<18*24>O, soft-GDR in ^<11>Li and GDR on the soft-GDR are investigated.