Reexamining Gamow-Teller decays near Ni 78

Decays of neutron-rich nuclei Zn 82, 83 and Ga 82, 83 produced in proton-induced fission of U 238 were studied at the Holifield Radioactive Ion Beam Facility using on-line mass separation and ?? ? spectroscopy techniques. New ?-ray transitions were identified and level schemes, which include states at high excitation energies in the range between 3?7 MeV were constructed. These high-energy levels were identified to be populated through allowed Gamow-Teller ? transitions, and their structure was interpreted with new shell-model calculations. A ?-delayed neutron branching ratio of 69?7% was deduced for Zn 82 and revised ?-decay half-life values of Zn 82 [155 (17)(20) ms] and Zn 83 [122 (28) ms] were determined.