Partial wave analysis of $J/\psi \to \gamma {\eta }^{\prime }{\eta }^{\prime }$

Using a sample of $\left(10.09±0.04\right)×{10}^{9}$ $J/\psi $ events collected with the BESIII detector, a partial wave analysis of $J/\psi \to \gamma {\eta }^{\prime }{\eta }^{\prime }$ is performed. The masses and widths of the observed resonances and their branching fractions are reported. The main contribution is from $J/\psi \to \gamma {f}_{0}\left(2020\right)$ with ${f}_{0}\left(2020\right)\to {\eta }^{\prime }{\eta }^{\prime }$, which is found with a significance of greater than $25\sigma $. The product branching fraction $B\left(J/\psi \to \gamma {f}_{0}\left(2020\right)\right)·B\left({f}_{0}\left(2020\right)\to {\eta }^{\prime }{\eta }^{\prime }\right)$ is measured to be $\left(2.63±0.06\left(\mathrm{stat}.{\right)}_{-0.46}^{+0.31}\left(\mathrm{syst}.\right)\right)×{10}^{-4}$.