Large-scale shell-model study for beta-decay properties of neutron-rich nuclei*

Beta decays in neutron-rich nuclei provide beneficial information on nuclear structure through their selective populations of states with specific spin/parity quantum numbers. Among them, the halflives of neutron-rich nuclei are important to elucidate r-process nucleosynthesis. In this talk, we present our shell-model study about the beta-decay properties of neutron-rich N=82, 81 isotones, some of which are r-process waiting point nuclides. The shell-model result shows excellent agreement with the experimental half-lives. We found that the low-energy peak of the Gamow Teller transition increases as the proton number

decreases from Z=50 to Z=40 due to the shell evolution. In addition, the beta-decay half-lives of neutron-rich nuclei of A~40 nuclei

are estimated by the shell-model calculations including the recently measured data at the FRIB facility.