Abstract
The exotic decay mode of has been directly observed for the first time in the Day-one experiment at the Beijing Radioactive Ion-beam Facility. The source was produced by using a 100-MeV proton beam bombarding a stack of microporous MgO thick target and delivered as an intense mass separated beam after online ionization. A high-efficiency simultaneous measurement of , and transitions enables the -delayed and coincidence spectroscopy. Three exotic decay sequences in are discovered, which expands the rare decay modes observed in decay. Moreover, a –decay sequence to the 6130-keV state of is observed, which is likely through the -keV state in . The experimentally deduced and are compared to the shell-model calculation, the allowed transition strengths can be well accounted for by using shell-model space interactions.
- Received 28 May 2020
- Revised 5 January 2021
- Accepted 11 January 2021
DOI:https://doi.org/10.1103/PhysRevC.103.L011301
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