Abstract
-decay spectroscopy of the proton-rich nucleus was performed. The decay scheme was reconstructed from results of delayed -ray and proton measurements. We observed two branches to bound states in for the first time. The branching ratios were determined to be and for the state at MeV and the state at MeV, respectively. The observation of an allowed transition to the -MeV state enabled us to firmly determine its spin-parity as . In the proton measurements performed with the method, we observed a new unbound level at MeV. The branching ratios to three unbound states, including the new level, were also determined for the first time. Based on the decay scheme, the values of were deduced. The values were smaller than those of the mirror nucleus by and for the and states, respectively. The mirror asymmetries of , observed in both the and the states, indicate changes in configuration in the wave function associated with the Thomas-Ehrman shift. To clarify the mechanism of this asymmetry, a comparison with shell-model calculations is also discussed. The calculations attribute the changes in configuration to the lowering of the orbital.
2 More- Received 26 June 2009
DOI:https://doi.org/10.1103/PhysRevC.80.044302
©2009 American Physical Society