Search for the charmonium semi-leptonic weak decay $J/\psi\rightarrow D_s^-e^+\nu_e+c.c.$

TL;DR

This study conducted a highly sensitive search for the rare semileptonic decay of the $J/\psi$ particle into $D_s^-$, $e^+$, and $ u_e$, setting the most stringent upper limit to date and testing Standard Model predictions.

Contribution

First experimental search for the $J/\psi \rightarrow D_s^- e^+ \nu_e$ decay with an improved upper limit, constraining new physics in heavy-quark interactions.

Findings

No significant signal observed.

Upper limit on branching fraction set at $9.9 \times 10^{-8}$.

Result improves previous constraints by an order of magnitude.

Abstract

Using a data sample of $(10087 \pm 44) \times 10^6$ $J/\psi$ events collected with the BESIII detector at a centre-of-mass energy of $\sqrt{s}=3.097\ \textrm{GeV}$, a dedicated search for the charmonium semileptonic weak decay $J/\psi\rightarrow D_s^-e^+\nu_e + \text{c.c.}$ is performed. No significant signal is observed. An upper limit on the branching fraction is set at $\mathcal{B}(J/\psi\rightarrow D_s^- e^+ \nu_e + \text{c.c.}) < 9.9 \times 10^{-8}$ at the 90\% confidence level. This result improves upon previous constraints by an order of magnitude, representing the most stringent experimental limit to date. It thus provides a critical test of Standard Model predictions and new physics scenarios in heavy-quark dynamics.