Search for the rare decay of $\psi(3686) \rightarrow \Lambda_c^+ \overline{p} e^+ e^- + c.c.$ at BESIII

TL;DR

This study searches for a rare decay of the $ ext{psi}(3686)$ particle into a specific baryonic final state with an electron-positron pair, setting an upper limit on its occurrence and finding no evidence of physics beyond the Standard Model.

Contribution

First experimental search for the flavor changing neutral current decay of $ ext{psi}(3686)$ into $ ext{Lambda}_c^+ ar{p} e^+ e^-$, establishing an upper limit on its branching fraction.

Findings

No signal observed for the decay.

Upper limit on branching fraction set at $1.7 imes 10^{-6}$.

Results consistent with Standard Model predictions.

Abstract

Based on a data sample of $(448.1\pm2.9)\times10^6~\psi(3686)$ decays collected with the BESIII experiment, a search for the flavor changing neutral current transition $\psi(3686)\rightarrow \Lambda_c^+ \overline{p} e^+ e^- + c.c.$ is performed for the first time. No signal candidates are observed and the upper limit on the branching fraction of $\psi(3686)\rightarrow \Lambda_c^+ \overline{p} e^+ e^-$ is determined to be $1.7\times10^{-6}$ at the 90\% confidence level. The result is consistent with expectations from the Standard Model, and no evidence for new physics is found.