Measurement of Branching Fractions of Singly Cabibbo-suppressed Decays Λc+→Σ0K+ And

Based on a sample of $4.\text{5 }{\mathrm{fb}}^{\ensuremath{-}1}$ of ${e}^{+}{e}^{\ensuremath{-}}$ annihilation data collected in the energy region between 4.6 GeV and 4.7 GeV with the BESIII detector at BEPCII, two singly Cabibbo-suppressed decays ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{0}{K}^{+}$ and ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{+}{K}_{S}^{0}$ are studied. The ratio of the branching fraction $\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{0}{K}^{+})$ relative to $\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{0}{\ensuremath{\pi}}^{+})$ is measured to be $0.0361\ifmmode\pm\else\textpm\fi{}0.0073(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.0005(\mathrm{syst}.)$, and the ratio of $\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{+}{K}_{S}^{0})$ relative to $\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{+}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})$ is measured to be $0.0106\ifmmode\pm\else\textpm\fi{}0.0031(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.0004(\mathrm{syst}.)$. After taking the world-average branching fractions of the reference decay channels, the branching fractions $\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{0}{K}^{+})$ and $\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{+}{K}_{S}^{0})$ are determined to be $(4.7\ifmmode\pm\else\textpm\fi{}0.9(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.1(\mathrm{syst}.)\ifmmode\pm\else\textpm\fi{}0.3(\mathrm{ref}.))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ and $(4.8\ifmmode\pm\else\textpm\fi{}1.4(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.2(\mathrm{syst}.)\ifmmode\pm\else\textpm\fi{}0.3(\mathrm{ref}.))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$, respectively. The branching fraction of the ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}^{+}{K}_{S}^{0}$ decay is measured for the first time.