Inclusive Semilectronic Decay of the $D_s$ Meson

We present an analysis of the inclusive semielectronic decay of the $D_s$ meson using data collected with the BESIII detector at the BEPCII storage ring in Beijing, China. Our data sample consists of an integrated luminosity of $3.19 \text{ fb}^{-1}$ of $e^+e^-$ annihilations collected at $E_{CM}=4.178 \text{ GeV}$, at which energy $D_s$ production is maximal, with a $\sim 1$ nb cross section for $e^+e^- \rightarrow D_sD_s^*$. We employ a tagged analysis with the use of particle identification and tracking matrix unfolding procedures to obtain our result. An input/output check with a Monte Carlo sample 5 times larger than data demonstrates the validity of our analysis procedure. Our principal results are the world’s most precise measurement of the $D_s$ meson semielectronic branching fraction, improved constraints on the rates for hitherto unobserved exclusive semielectronic modes and the ratio of $D_s$ and $D^0$ semielectronic widths. Prospects for additional studies of inclusive semileptonic $D_s$ decays with BESIII will also be described.