Search for the decay ${\eta }^{\prime }\to \gamma \gamma \eta$

Abstract

Using a data sample of $1.31\times 10^{9}J/\psi$ events collected with the BESIII detector, a search for ${\eta }^{\prime }\to \gamma \gamma \eta$ via $J/\psi \to \gamma {\eta }^{\prime }$ is performed for the first time. No significant ${\eta }^{\prime }$ signal is observed in the $\gamma \gamma \eta$ invariant mass spectrum, and the %upper limit of the branching fraction of ${\eta }^{\prime }\to \gamma \gamma \eta$ is determined to be less than $1.33\times 10^{-4}$ at the 90$\%$ confidence level.