Search for the electromagnetic Dalitz decays $\ddot{I}{‡}_{cJ}\to e^{+}{e}^{-}\ddot{I}•$

Abstract

Using a data sample of $(2.712\pm 0.014)\times 10^9$ $\ddot{I}ˆ(3686)$ events collected at $\sqrt{s}=3.686$ GeV by the BESIII detector, we search for the rare electromagnetic Dalitz decays $\ddot{I}{‡}_{cJ}\to e^{+}{e}^{-}\ddot{I}•(J=0,1,2)$ via the radiative transitions $\ddot{I}ˆ(3686)\to {\hat{I}}^3\ddot{I}{‡}_{cJ}$. No statistically significant $\ddot{I}{‡}_{cJ}\to e^{+}{e}^{-}\ddot{I}•$ signals are observed. The upper limits on the branching fractions of $\ddot{I}{‡}_{cJ}\to e^{+}{e}^{-}\ddot{I}•(J=0,1,2)$, excluding the $\ddot{I}•$ resonance to $e^{+}{e}^{-}$ final states, are set to be $2.4\times 10^{-7},6.7\times 10^{-7}$ and $4.1\times 10^{-7}$ at 90\% confidence level, respectively. This is the first search for the electromagnetic Dalitz transition of P-wave charmonium $\ddot{I}{‡}_{cJ}$ states to a light vector meson.