Collective 2p-2h intruder states in $^{118}\mathrm{Sn}$ studied via $\ensuremath{\beta}$ decay of $^{118}\mathrm{In}$ using the GRIFFIN spectrometer at TRIUMF

Collective 2p-2h intruder states in ${}^{118}{Sn}$ studied via $β$ decay of ${}^{118}{In}$ using the GRIFFIN spectrometer at TRIUMF

K. Ortner et al.

Phys. Rev. C 102, 024323 – Published 18 August 2020

Abstract

The low-lying structure of semimagic ${}^{118}{Sn}$ has been investigated through the $β$ decay of ${}^{118}{In}$ ( $T_{1 / 2} = 4.45$ min) to study shape coexistence via the reduced transition probabilities of states in the 2p-2h proton intruder band. This high-statistics study was carried out at TRIUMF-ISAC with the GRIFFIN spectrometer. In total, 99 transitions have been placed in the level scheme with 43 being newly observed. Three low-lying $γ$ -ray transitions with energies near 285 keV have been resolved from which the $2_{intr .}^{+} \to 0_{intr .}^{+}$ 284.52-keV transition was determined to have half of the previous branching fraction leading to a $B (E 2; 2_{2}^{+} \to 0_{2}^{+})$ of 21(4) W.u. compared to 39(7) W.u. from the previous measurement. Calculations using $s d$ IBM-2 with mixing have also been made to compare the experimental $B (E 2)$ values to the theoretical values and to make comparisons to the ${}^{114, 116}{Sn}$ isotopes previously studied using the same theoretical model.