中国物理学会高能物理分会第十三届全国粒子物理学术会议（2021）

The observed matter-antimatter asymmetry in the universe composes a serious challenge to our understanding of nature. BNV/LNV/cLFV decays have been searched in many experiments to understand this large-scale observed fact, and few in the case of $e^+e^-$ collision experiments are performed. In this talk, we present recent results to search for BNV and LNV/cLFV from $J/\psi$, $D^+$, $D^0$ and $\Sigma^+$ decays at the BESIII experiment. For the process with $\Delta B=2$, a search of $\Lambda$-$\bar\Lambda$ oscillation is performed with $J/\psi\to\Lambda\bar\Lambda$ events, and the oscillation rate and oscillation parameters are extracted.