Search for dark sector and rare decays at BESIII

TL;DR

The BESIII experiment utilizes its extensive data to investigate dark sector particles and rare decay processes, providing new experimental constraints and insights into beyond Standard Model physics.

Contribution

This paper reports recent experimental searches for dark matter, dark baryons, light vector bosons, and rare decays using BESIII data, highlighting novel search channels and results.

Findings

Constraints on sub-GeV dark matter in $ ext{eta} o ext{pi}^0 + ext{invisible}$

Search limits for dark baryon particles in $ ext{Xi}^- o ext{pi}^- + ext{invisible}$

Results on light vector bosons in $ ext{chi}_{cJ} o J/ X$, with $X o e^+ e^-$

Abstract

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 $\eta \to \pi^0 + \text{invisible}$ and $J/\psi \to \phi + \text{invisible}$, searches for dark baryon particles in $\Xi^- \to \pi^- +\rm{invisible}$, and searches for light vector bosons in $\chi_{cJ} \to J/\psi X$, where $X \to e^+ e^-$. In addition, we also present the recent rare decay searches, including a search for $\psi \to e \mu$, as well as searches for several baryon number and lepton number violation processes, and searches for various charmonium weak decays.