Measurements of the absolute branching fractions for Ds+→ηe+νe and Ds+→η′e+νe

Le résumé fourni par la source

By analyzing $482\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$ of ${e}^{+}{e}^{\ensuremath{-}}$ collision data collected at $\sqrt{s}=4.009\text{ }\text{ }\mathrm{GeV}$ with the BESIII detector at the BEPCII collider, we measure the absolute branching fractions for the semileptonic decays ${D}_{s}^{+}\ensuremath{\rightarrow}\ensuremath{\eta}{e}^{+}{\ensuremath{\nu}}_{e}$ and ${D}_{s}^{+}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{e}^{+}{\ensuremath{\nu}}_{e}$ to be $B({D}_{s}^{+}\ensuremath{\rightarrow}\ensuremath{\eta}{e}^{+}{\ensuremath{\nu}}_{e})=(2.30\ifmmode\pm\else\textpm\fi{}0.31\ifmmode\pm\else\textpm\fi{}0.08)%$ and $B({D}_{s}^{+}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{e}^{+}{\ensuremath{\nu}}_{e})=\phantom{\rule{0ex}{0ex}}(0.93\ifmmode\pm\else\textpm\fi{}0.30\ifmmode\pm\else\textpm\fi{}0.05)%$, respectively, and their ratio $\frac{B({D}_{s}^{+}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{e}^{+}{\ensuremath{\nu}}_{e})}{B({D}_{s}^{+}\ensuremath{\rightarrow}\ensuremath{\eta}{e}^{+}{\ensuremath{\nu}}_{e})}=0.40\ifmmode\pm\else\textpm\fi{}0.14\ifmmode\pm\else\textpm\fi{}0.02$, where the first uncertainties are statistical and the second ones are systematic. The results are in good agreement with previous measurements within uncertainties; they can be used to determine the $\ensuremath{\eta}\ensuremath{-}{\ensuremath{\eta}}^{\ensuremath{'}}$ mixing angle and improve upon the ${D}_{s}^{+}$ semileptonic branching ratio precision.

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