Measurements of the branching fractions for the semi-leptonic decays $D_s^{+}\to \varphi e^{+}{\nu }_e$, $\varphi {\mu }^{+}{\nu }_{\mu }$, $\eta {\mu }^{+}{\nu }_{\mu }$ and ${\eta }^{\prime }{\mu }^{+}{\nu }_{\mu }$

Abstract

By analyzing 482 pb${}^{-1}$ of $e^{+}{e}^{-}$ collision data collected at the center-of-mass energy $\sqrt{s}=4.009$ GeV with the BESIII detector, we measure the %absolute branching fractions for the semi-leptonic decays $D_s^{+}\to \varphi e^{+}{\nu }_e$, $\varphi {\mu }^{+}{\nu }_{\mu }$, $\eta {\mu }^{+}{\nu }_{\mu }$ and ${\eta }^{\prime }{\mu }^{+}{\nu }_{\mu }$ to be $\mathcal{B}(D_s^{+}\to \varphi e^{+}{\nu }_e)=(2.26\pm 0.45\pm 0.09)$\%, $\mathcal{B}(D_s^{+}\to \varphi {\mu }^{+}{\nu }_{\mu })=(1.94\pm 0.53\pm 0.09)$\%, $\mathcal{B}(D_s^{+}\to \eta {\mu }^{+}{\nu }_{\mu })=(2.42\pm 0.46\pm 0.11)$\% and $\mathcal{B}(D_s^{+}\to {\eta }^{\prime }{\mu }^{+}{\nu }_{\mu })=(1.06\pm 0.54\pm 0.07)$\%, where the first and second uncertainties are statistical and systematic, respectively. The branching fractions for the three semi-muonic decays $D_s^{+}\to \varphi {\mu }^{+}{\nu }_{\mu },\eta {\mu }^{+}{\nu }_{\mu }$ and ${\eta }^{\prime }{\mu }^{+}{\nu }_{\mu }$ are determined for the first time and that of $D_s^{+}\to \varphi e^{+}{\nu }_e$ is consistent with the world average value within uncertainties.

8 pages, 2 figures