Search for the leptonic decay $D^{+}\to e^{+}\nu_{e}$

TL;DR

This study searches for the rare leptonic decay $D^{+}\to e^{+}\nu_{e}$ using BESIII data, setting a new upper limit that is significantly more restrictive than previous results.

Contribution

The paper provides the most stringent upper limit to date on the branching fraction of $D^{+}\to e^{+}\nu_{e}$, improving previous constraints by an order of magnitude.

Findings

No significant signal observed for $D^{+}\to e^{+}\nu_{e}$.

Upper limit on branching fraction set at $9.7 \times 10^{-7}$.

Result constrains new physics models affecting leptonic charm decays.

Abstract

We search for the leptonic decay $D^+\to e^+\nu_{e}$ using an $e^+e^-$ collision data sample with an integrated luminosity of 20.3~fb$^{-1}$ collected with the BESIII detector at the center-of-mass energy of 3.773~GeV. No significant signal is observed and an upper limit on the branching fraction of $D^+\to e^+\nu_{e}$ is set as $9.7 \times 10^{-7}$, at the 90\% confidence level. Our upper limit is an order of magnitude smaller than the previous limit for this decay mode.