Measurements of $Λ^+_c$ Branching Fractions of Cabibbo-Suppressed Decay Modes involving $Λ$ and $Σ^{0}$
We measure the branching ratios of the Cabibbo-suppressed decays $Λ^+_c$ $\to$ $Λ$ $K^+$ and $Λ^+_c$ $\to$ $Σ^{0}$ $K^+$ %(measured with improved accuracy). relative to the Cabibbo-favored decay modes $Λ^+_c$ $\to$ $Λ$ $π^+$ and $Λ^+_c$ $\to$ $Σ^{0}$ $π^+$ to be $ 0.044 \pm 0.004 (\textnormal{stat.}) \pm 0.003 \ (\textnormal{syst.})$ and $ 0.039 \pm 0.005 (\textnormal{stat.}) \pm 0.003 (\textnormal{syst.})$, respectively. We set an upper limit on the branching ratio at 90 % confidence level for $Λ^+_c$ $\to$ $Λ$ $K^+ π^+ π^-$ to be $ 4.1 \times 10^{-2}$ relative to $Λ^+_c$ $\to$ $Λ$ $π^+$ and for $Λ^+_c$ $\to$ $Σ^{0}$ $K^+ π^+ π^-$ to be $ 2.0 \times 10^{-2}$ relative to $Λ^+_c$ $\to$ $Σ^{0}$ $π^+$. We also measure the branching fraction for the Cabibbo-favored mode $Λ^+_c$ $\to$ $Σ^{0}$ $π^+$ relative to $Λ^+_c$ $\to$ $Λ$ $π^+$ to be $0.977 \pm 0.015 (\textnormal{stat.}) \pm 0.051 (\textnormal{syst.})$. This analysis was performed using a data sample with an integrated luminosity of 125 fb$^{-1}$ collected by the $BABAR$ detector at the PEP-II asymmetric-energy $B$ factory at SLAC.