Measurements of branching fractions of $ {\Lambda}_c^{+}\to {\Sigma}^0{K}_S^0{\pi}^{+} $ and $ {\Lambda}_c^{+}\to {\Sigma}^0{K}_S^0{K}^{+} $

Based on a data sample corresponding to an integrated luminosity of 6.4 fb − 1 of e + e − annihilation and collected with the BESIII detector at 13 center-of-mass energy points ranging between 4.600 GeV and 4.950 GeV, we report the first observation of the singly Cabibbo-suppressed decay ${\Lambda}_c^{+}\to {\Sigma}^0{K}_S^0{\pi}^{+}$ with a statistical significance of 5.9 σ . The branching fraction is determined to be $B\left({\Lambda}_c^{+}\to {\Sigma}^0{K}_S^0{\pi}^{+}\right)=\left(0.58\pm 0.{14}_{\mathrm{stat}.}\pm 0.0{4}_{\mathrm{syst}.}\right)\times 1{0}^{-3}$ . In addition, the decay ${\Lambda}_c^{+}\to {\Sigma}^0{K}_S^0{K}^{+}$ has also been investigated, and the evidence for this decay is obtained with a statistical significance of 3.7 σ .