Search for dark sector and rare decays at BESIII
The BESIII experiment has collected a large data sample of charmonium, charm mesons, hyperons, and other light mesons. These data provide a unique opportunity to explore the dark sector and rare decays. We present recent dark sector results from the BESIII experiment, including searches for sub-GeV dark matter in $η\to π^0 + \text{invisible}$ and $J/ψ\to ϕ+ \text{invisible}$, searches for dark baryon particles in $Ξ^- \to π^- +\rm{invisible}$, and searches for light vector bosons in $χ_{cJ} \to J/ψX$, where $X \to e^+ e^-$. In addition, we also present the recent rare decay searches, including a search for $ψ\to e μ$, as well as searches for several baryon number and lepton number violation processes, and searches for various charmonium weak decays.