First measurements of the branching fractions of $J/\ddot{I}ˆ\to \hat{I}{ž}^0\bar{\hat{I}}›K_S^0+c.c.$, $J/\ddot{I}ˆ\to \hat{I}{ž}^0\bar{\hat{I}}{\pounds }^0{K}_S^0+c.c.$, and $J/\ddot{I}ˆ\to \hat{I}{ž}^0\bar{\hat{I}}{\pounds }^{-}{K}^{+}+c.c.$

Abstract

By analyzing $(10087\pm 44)\times 10^6$ $J/\ddot{I}ˆ$ events collected with the BESIII detector at the BEPCII, the decays $J/\ddot{I}ˆ\to \hat{I}{ž}^0\bar{\hat{I}}›K_S^0+c.c.$, $J/\ddot{I}ˆ\to \hat{I}{ž}^0\bar{\hat{I}}{\pounds }^0{K}_S^0+c.c.$, and $J/\ddot{I}ˆ\to \hat{I}{ž}^0\bar{\hat{I}}{\pounds }^{-}{K}^{+}+c.c.$ are observed for the first time. Their branching fractions are determined to be $\mathcal{B}(J/\ddot{I}ˆ\to \hat{I}{ž}^0\bar{\hat{I}}›K_S^0+c.c.)=(3.76\pm 0.14\pm 0.23)\times 10^{-5}$, $\mathcal{B}(J/\ddot{I}ˆ\to \hat{I}{ž}^0\bar{\hat{I}}{\pounds }^0{K}_S^0+c.c.)=(2.24\pm 0.32\pm 0.31)\times 10^{-5}$, and $\mathcal{B}(J/\ddot{I}ˆ\to \hat{I}{ž}^0\bar{\hat{I}}{\pounds }^{-}{K}^{+}+c.c.)=(5.64\pm 0.17\pm 0.28)\times 10^{-5}$, where the first uncertainties are statistical and the second systematic.