Measurements of Mixing Ratios in $^{\mathrm{116}}$Sn.

The $\beta $ decay of $^{\mathrm{116m1,g}}$In to $^{\mathrm{116}}$Sn, conducted at TRIUMF-ISAC utilizing the 8$\pi $ array of 20 HPGe detectors augmented with 5 Si(Li) detectors, produced a high statistics data set from which E2/M1 mixing ratios from $\gamma \gamma $ angular correlations were obtained. Several new mixing ratios were measured for the first time for transitions among the I$^{\mathrm{\pi }} \quad =$ 4$^{\mathrm{+}}$ states within $^{\mathrm{116}}$Sn. Additionally, a re-measurement of mixing ratios between the 2$_{\mathrm{2}}^{\mathrm{+}}$ to 2$_{\mathrm{1}}^{\mathrm{+}}$ and 2$_{\mathrm{3}}^{\mathrm{+}}$ to 2$_{\mathrm{1}}^{\mathrm{+}}$ states shows consistency with mixing ratio systematics in neighboring even-even tin isotopes. Previous analyses of $^{\mathrm{116}}$Sn have rationalized the nature and mixing of the 4$^{\mathrm{+}}$ states on the basis of shared phonon strength [1]. The results presented here demonstrate that generalized seniority, without the inclusion of vibrational components, may better describe these states. This has implications for ongoing theoretical and experimental research on $^{\mathrm{116}}$Sn and neighboring tin isotopes. [1] S. Raman \textit{et al.}, Phys Rev C 43 521 (1991)