The role of core excitations in the structure and decay of the 16(+) spin-gap isomer in Cd-96

P. J. Davies et al. -- 6 pags., 4 figs., 3 tabs.-- Open Access funded by Creative Commons Atribution Licence 4.0
The first evidence for β-delayed proton emission from the 16 spin gap isomer in Cd is presented. The data were obtained from the Rare Isotope Beam Factory, at the RIKEN Nishina Center, using the BigRIPS spectrometer and the EURICA decay station. βp branching ratios for the ground state and 16 isomer have been extracted along with more precise lifetimes for these states and the lifetime for the ground state decay of Cd. Large scale shell model (LSSM) calculations have been performed and WKB estimates made for ℓ=0,2,4 proton emission from three resonance-like states in Ag, that are populated by the β decay of the isomer, and the results compared to the new data. The calculations suggest that ℓ=2 proton emission from the resonance states, which reside ∼5 MeV above the proton separation energy, dominates the proton decay. The results highlight the importance of core-excited wavefunction components for the 16 state.
This work was partially supported by the German BMBF grant 05P12PKFNE, the UK Science and Technology Facilities Council(STFC) grants ST/J000124/1 and ST/L005727/1, and the U.S. DOE grant DE-FG02-91ER40609.