Measurements of the branching ratios for $6P_{1/2}$ decays in ${}^{138}$Ba${}^{+}$

Abstract

Measurement of the branching ratios for $6P_{1/2}$ decays to $6S_{1/2}$ and $5D_{3/2}$ in ${}^{138}$Ba${}^{+}$ are reported with the decay probability from $6P_{1/2}$ to $5D_{3/2}$ measured to be $p=0.268177\pm (37{)}_{\mathrm{stat}}-(20{)}_{\mathrm{sys}}$. This result differs from a recent report by $12\sigma$. A detailed account of systematics is given and the likely source of the discrepancy is identified. The new value of the branching ratio is combined with a previous experimental results to give a new estimate of $\tau =7.855(10)\mathrm{ns}$ for the $6P_{1/2}$ lifetime. In addition, ratios of matrix elements calculated from theory are combined with experimental results to provide improved theoretical estimates of the $6P_{3/2}$ lifetime and the associated matrix elements.

12 pages, 7 figure, updated corrected a few minor typos