Search for $ {\eta }_{c}(2S)\to {K}^{+}{K}^{-}{\eta }^{\prime }$ decay

Using $ (2.712\pm 0.014)\times {10}^{9}\text{}\text{}\psi (2S)$ events collected with the BESIII detector operating at the BEPCII, we search for the $ {\eta }_{c}(2S)\to {K}^{+}{K}^{-}{\eta }^{\prime }$ decay. Its decay branching fraction is measured to be $ (11.11\pm 4.6{7}_{(\mathrm{stat})}\pm 1.8{2}_{(\mathrm{syst})}\pm 4.2{4}_{(\mathrm{extr})})\times {10}^{-4}$, where the first uncertainty is statistical, the second is systematic, and the third uncertainty is from the branching fraction of the $ \psi (2S)\to \gamma {\eta }_{c}(2S)$ decay. The statistical significance is $ 2.8\sigma $. The upper limit on the product branching fraction $ B[\psi (2S)\to \gamma {\eta }_{c}(2S)]\times B[{\eta }_{c}(2S)\to {K}^{+}{K}^{-}{\eta }^{\prime }]$ is set to be $ 0.94\times {10}^{-6}$ at 90% confidence level. In addition, the branching fractions of $ {\chi }_{c1}\to {K}^{+}{K}^{-}{\eta }^{\prime }$ and $ {\chi }_{c2}\to {K}^{+}{K}^{-}{\eta }^{\prime }$ are updated to be $ (8.48\pm 0.10(\mathrm{stat})\pm 0.47(\mathrm{syst}))\times {10}^{-4}$ and $ (1.53\pm 0.04(\mathrm{stat})\pm 0.08(\mathrm{syst}))\times {10}^{-4}$, respectively. The precision is improved by twofold.