Electromagnetic and Weak Transitions in Halo Nuclei

Electromagnetic and weak transitions in halo nuclei are studied. Magnetic moment of ¹¹Be is analyzed and compared with a recent measurement. Probability of the |¹⁰Be (0⁺) × 1s_1/2> component in the wave function of ¹¹Be is found to be α² ≈ 65%. Coulomb displacement energy of the isobaric analog state of ¹¹Be is investigated, and the effects of the halo and the configuration of the halo wave function is discussed. A value of α² ~ 0.6 for the probability, consistent with the analysis of the magnetic moment, is obtained. A large breaking of the p-shell core in ¹²Be and ¹¹Li, that is, the breaking of magic number at N=8, is shown by analyses of GT transitions. Admixture of 0p_1/2 and 1s_1/2 shells with an almost equal weight in the halo of ¹¹Li is found to be important to obtain the soft dipole strength with two-peak structure in the low energy region.