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

Abstract

Based on $(2712.4\pm 14.3)\times 10^6$ $e^{+}{e}^{-}\to \ddot{I}ˆ(3686)$ events collected with the BESIII detector operating at the BEPCII collider, we report the first evidence of $\ddot{I}{‡}_{c0}\to \hat{I}›\bar{\hat{I}}›\ddot{I}•$ decays and the first observation of $\ddot{I}{‡}_{c1,2}\to \hat{I}›\bar{\hat{I}}›\ddot{I}•$ decays, with significances of $4.5\ddot{I}ƒ$, $11.3\ddot{I}ƒ$ and $13.0\ddot{I}ƒ$, respectively. The decay branching fractions of $\ddot{I}{‡}_{c0,1,2}\to \hat{I}›\bar{\hat{I}}›\ddot{I}•$ are measured to be $(2.99\pm 1.24\pm 0.19)\times 10^{-5}$, $(6.01\pm 0.90\pm 0.40)\times 10^{-5}$, and $(7.13\pm 0.81\pm 0.36)\times 10^{-5}$, where the first uncertainties are statistical and the second systematic. No obvious enhancement near the $\hat{I}›\bar{\hat{I}}›$ production threshold or excited $\hat{I}›$ state is found in the $\hat{I}›\ddot{I}•$ (or $\bar{\hat{I}}›\ddot{I}•$) system.

10 pages, 9 figures