Two-phonon structures for beta-decay theory

The β-decay rates of ⁶⁰Ca 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 ⁶⁰Sc, the spin-parity of the ground state is found to be 1+. We predict that the half-life of ⁶⁰Ca is 0.3 ms, while the total probability of the βxn emission is 6:1%. Additionally, the random matrix theory has been applied to analyze the statistical properties of the 1⁺ spectrum populated in the β-decay to elucidate the obtained results.