Light meson decays at BESIII

Abstract

The world's largest sample of $J/ψ$ events accumulated with the BESIII detector offers a unique opportunity to investigate $η$ and $η'$ physics via the radiative transition processes $J/ψ\to γη/η'$. A selection of recent highlights in light meson spectroscopy achieved at BESIII is reviewed in these proceedings, including evidence for the cusp effect in $η' \to π^0π^0η$, precision studies of the decay mechanisms of $η\to 3π$ and $η' \to 4π$, electromagnetic transition form factor measurements with $η/η' \to γe^+e^-$ and $η' \to π^+π^-l^+l^-$, as well as searches for rare decays of $η$ and $η'$ into lepton pairs, including $η\to l^+l^-$ and $η/η' \to l^+l^-l^+l^-$~($l = e, μ$).