Phys. Rev. C 100, 011302(R) (2019) - Observation of a $\ensuremath{\mu}\text{s}$ isomer in $_{\phantom{\rule{0.16em}{0ex}}\phantom{\rule{0.16em}{0ex}}\phantom{\rule{0.16em}{0ex}}49}^{134}\mathrm{In}_{85}$: Proton-neutron coupling ``southeast'' of $_{\phantom{\rule{0.16em}{0ex}}\phantom{\rule{0.16em}{0ex}}\phantom{\rule{0.16em}{0ex}}50}^{132}\mathrm{Sn}

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Observation of a $μ s$ isomer in ${}_{49}^{134}{In}_{85}$ : Proton-neutron coupling “southeast” of ${}_{50}^{132}{Sn}_{82}$

V. H. Phong et al.

Phys. Rev. C 100, 011302(R) – Published 29 July 2019

Abstract

We report on the observation of a microsecond isomeric state in the single-proton-hole, three-neutron-particle nucleus ${}^{134}{In}$ . The nuclei of interest were produced by in-flight fission of a ${}^{238}U$ beam at the Radioactive Isotope Beam Factory at RIKEN. The isomer depopulates through a $γ$ ray of energy 56.7(1) keV and with a half-life of $T_{1 / 2} = 3.5 (4) μ s$ . Based on the comparison with shell-model calculations, we interpret the isomer as the $I^{π} = 5^{-}$ member of the $π 0 g_{9 / 2}^{- 1} \otimes ν 1 f_{7 / 2}^{3}$ multiplet, decaying to the $I^{π} = 7^{-}$ ground state with a reduced-transition probability of $B (E 2; 5^{-} \to 7^{-}) = 0.53 (6) W . u .$ Observation of this isomer, and lack of evidence in the current work for a $I^{π} = 5^{-}$ isomer decay in ${}^{132}{In}$ , provides a benchmark of the proton-neutron interaction in the region of the nuclear chart “southeast” of ${}^{132}{Sn}$ , where experimental information on excited states is sparse.