Observation of $D^{0(+)}\to K_S^0\ddot{I}{€}^{0(+)}\hat{I}{\cdot }^{\prime }$ and improved measurement of $D^0\to K^{-}\ddot{I}{€}^{+}\hat{I}{\cdot }^{\prime }$

Abstract

By analyzing $2.93\mathrm{f}{\mathrm{b}}^{-1}$ of data taken at a center-of-mass energy of 3.773~GeV with the BESIII detector, we measure the branching fractions of the Cabibbo-favored hadronic decays $D^0\to K^{-}\ddot{I}{€}^{+}\hat{I}{\cdot }^{\prime }$, $D^0\to K_S^0\ddot{I}{€}^0\hat{I}{\cdot }^{\prime }$ and $D^{+}\to K_S^0\ddot{I}{€}^{+}\hat{I}{\cdot }^{\prime }$, which are determined to be $(6.43\pm 0.15_{stat.}\pm 0.31_{syst.})\times 10^{-3}$, $(2.52\pm 0.22_{stat.}\pm 0.15_{syst.})\times 10^{-3}$ and $(1.90\pm 0.17_{stat.}\pm 0.13_{syst.})\times 10^{-3}$, respectively. The precision of the branching fraction of $D^0\to K^{-}\ddot{I}{€}^{+}\hat{I}{\cdot }^{\prime }$ is significantly improved, and the processes $D^0\to K_S^0\ddot{I}{€}^0\hat{I}{\cdot }^{\prime }$ and $D^{+}\to K_S^0\ddot{I}{€}^{+}\hat{I}{\cdot }^{\prime }$ are observed for the first time.