Search for the double Dalitz decays $\hat{I}\cdot /\hat{I}{\cdot }^{\prime }\to e^{+}{e}^{-}\hat{I}{¼}^{+}\hat{I}{¼}^{-}$ and $\hat{I}{\cdot }^{\prime }\to \hat{I}{¼}^{+}\hat{I}{¼}^{-}\hat{I}{¼}^{+}\hat{I}{¼}^{-}$

BESIII Collaboration, M. Ablikim, M. N. Achasov +653

Using a data sample of $(10087\pm 44)\times 10^6$ $J/\ddot{I}ˆ$ events collected with the BESIII detector, we search for the decays $\hat{I}\cdot /\hat{I}{\cdot }^{\prime }\to e^{+}{e}^{-}\hat{I}{¼}^{+}\hat{I}{¼}^{-}$ and $η' \to μ^+μ^-Î…