Study of the $\ddot{I}{‡}_{cJ}\to \hat{I}›\bar{\hat{I}}›\hat{I}{\cdot }^{\prime }$ decays

Abstract

Using a data sample of $(2.712\pm 0.014)\times 10^9$ $\ddot{I}ˆ(3686)$ events collected with the BESIII detector at the BEPCII collider, we investigate the decays $\ddot{I}{‡}_{cJ}\to \hat{I}›\bar{\hat{I}}›\hat{I}{\cdot }^{\prime }$ for $J=0,1,2$ via the radiative transition $\ddot{I}ˆ(3686)\to {\hat{I}}^3\ddot{I}{‡}_{cJ}$. The decays $\ddot{I}{‡}_{c0,2}\to \hat{I}›\bar{\hat{I}}›\hat{I}{\cdot }^{\prime }$ are observed for the first time, with statistical significances of 6.7$\ddot{I}ƒ$ and 6.4$\ddot{I}ƒ$, respectively. Evidence for the decay $\ddot{I}{‡}_{c1}\to \hat{I}›\bar{\hat{I}}›\hat{I}{\cdot }^{\prime }$ is found with a statistical significance of 3.3$\ddot{I}ƒ$. The corresponding branching fractions are measured to be $\mathcal{B}(\ddot{I}{‡}_{c0}\to \hat{I}›\bar{\hat{I}}›\hat{I}{\cdot }^{\prime })=(7.56\pm 1.42\pm 0.90)\times 10^{-5}$, $\mathcal{B}(\ddot{I}{‡}_{c1}\to \hat{I}›\bar{\hat{I}}›\hat{I}{\cdot }^{\prime })=(1.54\pm 0.51\pm 0.16)\times 10^{-5}$, and $\mathcal{B}(\ddot{I}{‡}_{c2}\to \hat{I}›\bar{\hat{I}}›\hat{I}{\cdot }^{\prime })=(3.03\pm 0.61\pm 0.29)\times 10^{-5}$, where the first uncertainties are statistical and the second systematic. No significant excited $\hat{I}›$ baryon states or $\hat{I}›\bar{\hat{I}}›$ near-threshold enhancements are observed.