Abstract
States above the known 6 s isomer in have been populated with the (,) reaction at a beam energy of 180 MeV at the University of Jyväskylä, Finland. The recoil-isomer tagging technique was utilized to correlate delayed -ray decays, detected in the GREAT focal plane spectrometer, with prompt decays measured in the JUROGAM II spectrometer at the target position. The lifetime of the isomeric state has been remeasured as 6.2(2) s. Two high-lying strongly coupled bands have been established with . Potential-energy surface calculations, in conjunction with factor measurements, reveal that they are built upon four-quasiparticle structures comprising two-quasineutron plus two-quasiproton configurations. The short half-life or lack of hindrance for the decays from these four-quasiparticle band-head states is reasoned to be a consequence of increased triaxial deformation and mixing due to the high density of states relative to the lower two-quasiparticle 6-s isomeric state.
1 More- Received 12 November 2010
DOI:https://doi.org/10.1103/PhysRevC.83.034311
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