Search for the leptonic decays $D^{\ast +}\to e^{+}{\nu }_e$ and $D^{\ast +}\to {\mu }^{+}{\nu }_{\mu }$

Abstract

We present the first search for the leptonic decays $D^{\ast +}\to e^{+}{\nu }_e$ and $D^{\ast +}\to {\mu }^{+}{\nu }_{\mu }$ by analyzing a data sample of electron-positron collisions recorded with the BESIII detector at center-of-mass energies between 4.178 and 4.226 GeV, corresponding to an integrated luminosity of 6.32~fb${}^{-1}$. No significant signal is observed. The upper limits on the branching fractions for $D^{\ast +}\to e^{+}{\nu }_e$ and $D^{\ast +}\to {\mu }^{+}{\nu }_{\mu }$ are set to be $1.1\times 10^{-5}$ and $4.3\times 10^{-6}$ at 90\% confidence level, respectively.

14 pages, 7 figures