Improved measurements of branching fractions for $\hat{I}{\cdot }_c\to \ddot{I}•\ddot{I}•$ and $\ddot{I}‰\ddot{I}•$

Abstract

Using $(223.7\pm 1.4)\times 10^6$ J/$\ddot{I}ˆ$ events accumulated with the BESIII detector, we study $\hat{I}{\cdot }_c$ decays to $\ddot{I}•\ddot{I}•$ and $\ddot{I}‰\ddot{I}•$ final states. The branching fraction of $\hat{I}{\cdot }_c\to \ddot{I}•\ddot{I}•$ is measured to be $Br(\hat{I}{\cdot }_c\to \ddot{I}•\ddot{I}•)=(2.5\pm 0.3_{-0.7}^{+0.3}\pm 0.6)\times 10^{-3}$, where the first uncertainty is statistical, the second is systematic, and the third is from the uncertainty of $Br(J/\ddot{I}ˆ\to {\hat{I}}^3\hat{I}{\cdot }_c)$. No significant signal for the double OZI-suppressed decay of $\hat{I}{\cdot }_c\to \ddot{I}‰\ddot{I}•$ is observed, and the upper limit on the branching fraction is determined to be $Br(\hat{I}{\cdot }_c\to \ddot{I}‰\ddot{I}•)<2.5\times 10^{-4}$ at the 90\% confidence level.