Observation of $\Lambda_c^+ \to \Lambda^0 K^+$, $\Lambda_c^+ \to \Sigma^0 K^+$ and $\Lambda_c^+ \to \Sigma^+ K^+\pi^-$ decays

Abstract

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