An overview of $\eta$ and ${\eta }^{\prime }$ decays at BESIII

Abstract

The world's largest sample of 1.31 billion $J/\psi$ events accumulated at the BESIII detector, provides a unique opportunity to investigate $\eta$ and ${\eta }^{\prime }$ physics via two body $J/\psi$ radiative or hadronic decays. For many ${\eta }^{\prime }$ decay channels the low background data samples are up to three orders of magnitude larger than collected in any previous experiment. Here we review the most significant results on $\eta$ and ${\eta }^{\prime }$ obtained at BESIII so far. The analyses range from detailed studies of the common decays dynamics, observations of new radiative and Dalitz decays, and search for rare/forbidden decays with sensitivity up to $\mathcal{B}\sim 10^{-5}$. Finally, prospects of the forthcoming runs at $J/\psi$ peak for the $\eta$ and ${\eta }^{\prime }$ physics are discussed.

17pages. 20 figures