Measurement of the branching fraction of $\hat{I}\cdot \to \hat{I}{¼}^{+}\hat{I}{¼}^{-}$ and search for $\hat{I}\cdot \to e^{+}{e}^{-}$

BESIII Collaboration, M. Ablikim, M. N. Achasov +702

We analyze the decay of $\hat{I}\cdot \to {\ell }^{+}{\ell }^{-}(\ell =e,\hat{I}¼)$ via $J/\ddot{I}ˆ\to {\hat{I}}^3\hat{I}{\cdot }^{\prime }$ and $\hat{I}{\cdot }^{\prime }\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}\hat{I}\cdot$, based on (10087 $\pm$ 44) $\times$ 10${}^6$ $J/\ddot{I}ˆ$ event…