Decay spectroscopy of 160Sm: The lightest four-quasiparticle K isomer

Z Patel,Z Patel,D Kameda,M Matsushita,A Odahara,H Baba,E Şahin,C.-B Moon,I Kojouharov,H Watanabe,Zs Podolyák,S Go,G Lorusso,J Taprogge,J Taprogge,H Schaffner,Y Fang,T Isobe,I Nishizuka,F Browne,F Browne,R Daido,N Fukuda,S Nishimura,Z Li,P.-A Söderström,G Lorusso,T Sumikama,A Yagi,N Inabe,E Ideguchi,P Doornenbal,S Rice,G Gey,S Michimasa,G Benzoni,K Kobayashi,I Kuti,L Sinclair,A Gottardo,R Yokoyama,P.H Regan,P.H Regan,Zs Dombrádi,L Sinclair,N Kurz,H Watanabe,Zs Vajta,T Kubo,S Rice,T Komatsubara,M Tanaka,J Wu,J Wu,N Aoi,H Sakuraï ,Masao Kobayashi ,F L Bello Garrote ,Z Y Xu ,Hiroshi Suzuki ,Hiroyuki Takeda ,G S Simpson ,G S Simpson ,G S Simpson ,H Nıshıbata ,P M Walker ,G S Simpson ,F R Xu ,H L Liu

doi:10.1016/j.physletb.2015.12.026

Abstract

The decay of a new four-quasiparticle isomeric state in 160Sm has been observed using γ-ray spectroscopy at the RIBF, RIKEN. The four-quasiparticle state is assigned a 2π⊗2νπ52−[532], π52+[413], ν52−[523], ν72+[633] configuration. The half-life of this (11+) state is measured to be 1.8(4) μs. The (11+) isomer decays into a rotational band structure, based on a (6−) ν52−[523]⊗ν72+[633] bandhead, consistent with the gK−gR values. This decays to a (5−) two-proton quasiparticle state, which in turn decays to the ground state band. Potential energy surface and blocked-BCS calculations were performed in the deformed midshell region around 160Sm. They reveal a significant influence from β6 deformation and that 160Sm is the best candidate for the lightest four-quasiparticle K isomer to exist in this region. The relationship between reduced hindrance and isomer excitation energy for E1 transitions from multiquasiparticle states is considered with the new data from 160Sm. The E1 data are found to agree with the existing relationship for E2 transitions.

Highlights

The decay of a new four-quasiparticle isomeric state in 160Sm has been observed using γ -ray spectroscopy at the RIBF, RIKEN
Potential energy surface and blocked-BCS calculations were performed in the deformed midshell region around 160Sm
Patel et al / Physics Letters B 753 (2016) 182–186 and that 160Sm is the best candidate for the lightest four-quasiparticle K isomer to exist in this region

Summary

Introduction

The decay of a new four-quasiparticle isomeric state in 160Sm has been observed using γ -ray spectroscopy at the RIBF, RIKEN. The decay of a new four-quasiparticle isomeric state in 160Sm has been observed using γ -ray spectroscopy at the The nucleus is isomeric when the transition to a lower energy state with a different K value is inhibited by the

Results

Conclusion