Measurement of branching fractions for ${\Lambda }_{c}^{+}\to n{K}_{S}^{0}{\pi }^{+}$ and ${\Lambda }_{c}^{+}\to n{K}_{S}^{0}{K}^{+}$

Based on $4.5\text{}\text{}{\mathrm{fb}}^{-1}$ of ${e}^{+}{e}^{-}$ collision data accumulated at center-of-mass energies between 4599.53 and 4698.82 MeV with the BESIII detector, we measure the absolute branching fraction of the Cabibbo-favored decay ${\Lambda }_{c}^{+}\to n{K}_{S}^{0}{\pi }^{+}$ with the precision improved by a factor of 2.8 and report the first evidence for the singly-Cabibbo-suppressed decay ${\Lambda }_{c}^{+}\to n{K}_{S}^{0}{K}^{+}$. The branching fractions for ${\Lambda }_{c}^{+}\to n{K}_{S}^{0}{\pi }^{+}$ and ${\Lambda }_{c}^{+}\to n{K}_{S}^{0}{K}^{+}$ are determined to be $\left(1.86±0.08±0.04\right)×{10}^{-2}$ and $\left(3.{9}_{-1.4}^{+1.7}±0.3\right)×1{0}^{-4}$, respectively, where the first uncertainties are statistical and the second ones are systematic.