Measurements of the absolute branching fractions of $\hat{I}{\text{c◯}}^{-}$ decays and test of the $\hat{I}”I=1/2$ rule

Abstract

Based on a data set of $(27.12\pm 0.10)\times 10^8$ $\ddot{I}ˆ(3686)$ events collected at the BESIII experiment, the absolute branching fractions of the three dominant $\hat{I}{\text{c◯}}^{-}$ decays are measured to be ${\mathcal{B}}_{\hat{I}{\text{c◯}}^{-}\to \hat{I}{ž}^0\ddot{I}{€}^{-}}=(25.03\pm 0.44\pm 0.53)\%$, ${\mathcal{B}}_{\hat{I}{\text{c◯}}^{-}\to \hat{I}{ž}^{-}\ddot{I}{€}^0}=(8.43\pm 0.52\pm 0.28)\%$, and ${\mathcal{B}}_{\hat{I}{\text{c◯}}^{-}\to \hat{I}›K^{-}}=(66.3\pm 0.8\pm 2.0)\%$, where the first and second uncertainties are statistical and systematic, respectively. The ratio between ${\mathcal{B}}_{\hat{I}{\text{c◯}}^{-}\to \hat{I}{ž}^0\ddot{I}{€}^{-}}$ and ${\mathcal{B}}_{\hat{I}{\text{c◯}}^{-}\to \hat{I}{ž}^{-}\ddot{I}{€}^0}$ is determined to be $2.97\pm 0.19\pm 0.11$, which is in good agreement with the PDG value of $2.74\pm 0.15$, but greater by more than four standard deviations than the theoretical prediction of 2 obtained from the $\hat{I}”I=1/2$ rule.