The $\beta$ decay of $^{81}$Zn and excitations of the $^{78}$Ni core
ORAL
Abstract
The $\beta$ decay of the neutron rich N=51 nucleus $^{81}$Zn was investigated in order to establish the ground state configuration of $^{81}$Zn and to study excited states in the N=50 isotone $^{81}$Ga. A high detection efficiency, digital $\beta$$\gamma$ spectroscopy setup at the HRIBF (Oak Ridge) was used with an isotopically pure beam of $^{81}$Zn. The $^{81}$Zn decay properties result from a competition between high energy forbidden $\beta$ decays to negative parity states and allowed Gamow-Teller transitions to positive parity, core excited states in $^{81}$Ga. Our data on the $\beta$ decay branching ratios suggest a 5/2$^+$ assignment for the $^{81}$Zn ground state. The analysis also establishes the N=50 shell gap energy near $^{78}$Ni.
*NNSA, DOE Cooperative Agreement DE-FG52-08NA28552
