β-decay spectroscopy of Ho173,174 (Z = 67, N = 106,107) was conducted at Radioactive Isotope Beam Factory at RIKEN by using in-flight fission of a 345-MeV/u U238 primary beam. A previously unreported isomeric state at 405 keV with half-life of 3.7(12) μs and a spin and parity of (3/2+) is identified in Ho173. Moreover, a new state with a spin and parity of 9- was discovered in Er174. The experimental log ft values of 5.84(20) and 5.25(18) suggest an allowed-hindered β decay from the ground state of Ho174 to the Kπ=8- isomeric state in Er174. Configuration-constrained potential energy surface (PES) calculations were performed and the predictions are in reasonable agreement with the experimental results.
Bibliographical noteFunding Information:
This measurement was carried out at the RIBF operated by RIKEN Nishina Center and CNS, University of Tokyo, the EUROBALL Owners Committee for the loan of germanium detectors, the PreSpec Collaboration for the readout electronics of the cluster detectors. Part of the WAS3ABi was supported by the Rare Isotopes Science Project which is funded by MSIP and NRF of Korea. This work was supported by JSPS KAKENHI Grants No. 24740188, No. 25247045, and No. 25287065, STFC (UK authors), the UK National Measurement Office (P.H.R.), the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contract No. DE-AC02-06CH11357 (F.G.K.), NRF Korea Grants No. 2016R1D1A1A09917463, No. 2017M2A2A6A02071071 (C.S.L.), No. 2019R1F1A1058370, and No. 2016R1A5A1013277 (K.Y.C.), and Science Foundation Ireland under Grant No. 12/IP/1288 (O.J.R.).
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