Two-Phonon Structures For Beta-Decay Theory

The beta-decay rates of Ca-60 have been studied within a microscopic model, which is based on the Skyrme interaction T45 to construct single-particle and phonon spaces. We observe a redistribution of the Gamow-Teller strength due to the phonon-phonon coupling, considered in the model. For Sc-60, the spin-parity of the ground state is found to be 1(+). We predict that the half-life of Ca-60 is 0.3 ms, while the total probability of the beta xn emission is 6.1%. Additionally, the random matrix theory has been applied to analyze the statistical properties of the 1(+) spectrum populated in the beta-decay to elucidate the obtained results.