Abstract
The existence of two close-lying nuclear states in has recently been experimentally determined: a spin-parity for the ground state was measured in a laser spectroscopy experiment, while a level was observed in transfer reactions. This scenario is supported by Coulomb excitation studies, which set a limit for the energy splitting of 0.8 keV. In this work, we report on the study of the excited structure of populated in the decay of produced at ISOLDE, CERN. Using -gated, -ray singles, and coincidences, we have searched for energy differences to try to delimit the ground-state energy splitting, providing a more stringent energy difference limit. Three new half-lives of excited states in have been measured using the fast-timing method with (Ce) detectors. From our study, we help clarify the excited structure of and we extend the existing decay to with 8 new energy levels and 35 transitions. We observe a 195-keV transition consistent with a ray de-exciting a short-lived state in the -decay parent .
3 More- Received 25 April 2017
DOI:https://doi.org/10.1103/PhysRevC.96.034311
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