Measurement of Branching Fractions for $\hat{I}{›}_c^{+}\to n{K}_S^0\ddot{I}{€}^{+}$ and $\hat{I}{›}_c^{+}\to n{K}_S^0{K}^{+}$

Abstract

Based on 4.5 fb${}^{-1}$ of $e^{+}{e}^{-}$ collision data accumulated at center-of-mass energies between $4.600\mathrm{GeV}$ and $4.699\mathrm{GeV}$ with the BESIII detector, we measure the absolute branching fraction of the Cabibbo-favored decay $\hat{I}{›}_c^{+}\to n{K}_S^0\ddot{I}{€}^{+}$ with the precision improved by a factor of 2.8 and report the first evidence for the singly-Cabibbo-suppressed decay $\hat{I}{›}_c^{+}\to n{K}_S^0{K}^{+}$. The branching fractions for $\hat{I}{›}_c^{+}\to n{K}_S^0\ddot{I}{€}^{+}$ and $\hat{I}{›}_c^{+}\to n{K}_S^0{K}^{+}$ are determined to be $(1.86\pm 0.08\pm 0.04)\times 10^{-2}$ and $\left(3.9_{-1.4}^{+1.7}\pm 0.3\right)\times 10^{-4}$, respectively, where the first uncertainties are statistical and the second ones are systematic.

12 pages, 2 figures