Observation of $Λ_c^+ \to Λ^0 K^+$, $Λ_c^+ \to Σ^0 K^+$ and $Λ_c^+ \to Σ^+ K^+π^-$ decays

Abstract

We present measurements of the Cabibbo-suppressed decays $Λ_c^+ \to Λ^0 K^+$ and $Λ_c^+ \to Σ^0 K^+$ (both first observations), $Λ_c^+ \to Σ^+ K^+π^-$ (seen with large statistics for the first time), $Λ_c^+ \to p K^+ K^-$ and $Λ_c^+ \to p ϕ$ (measured with improved accuracy). Improved branching ratio measurements for the decays $Λ_c^+ \to Σ^0 K^+ K^-$ and $Λ_c^+ \to Σ^0 ϕ$, which are attributed to W-exchange diagrams, are shown. We also present the first evidence for $Λ_c^+ \to Ξ(1690) K^+$ and set an upper limit on non-resonant $Λ_c^+ \to Σ^0 K^+ K^-$ decay. This analysis was performed using 23.6 fb$^{-1}$ of data collected by the Belle detector at the $e^+ e^-$ asymmetric collider KEKB.