Evidence for the singly Cabibbo-suppressed decay Ω c 0 → Ξ − π + $$ {\Omega}_c^0\to {\Xi}^{-}{\pi}^{+} $$ and search for Ω c 0 → Ξ − K + $$ {\Omega}_c^0\to {\Xi}^{-}{K}^{+} $$ and Ω − K + decays at Belle

Abstract Using a data sample of 980 fb −1 collected with the Belle detector at the KEKB asymmetric-energy e + e − collider, we study for the first time the singly Cabibbo-suppressed decays Ω c 0 → Ξ − π + $$ {\Omega}_c^0\to {\Xi}^{-}{\pi}^{+} $$ and Ω − K + and the doubly Cabibbo-suppressed decay Ω c 0 → Ξ − K + $$ {\Omega}_c^0\to {\Xi}^{-}{K}^{+} $$ . Evidence for an Ω c 0 $$ {\Omega}_c^0 $$ signal in the Ω c 0 $$ {\Omega}_c^0 $$ → Ξ − π + mode is reported with a significance of 4.5σ including systematic uncertainties. The ratio of branching fractions to the normalization mode Ω c 0 $$ {\Omega}_c^0 $$ → Ω − π + is measured to be B Ω c 0 → Ξ − π + / B Ω c 0 → Ω − π + = 0.253 ± 0.052 stat . ± 0.030 syst . . $$ \mathcal{B}\left({\Omega}_c^0\to {\Xi}^{-}{\pi}^{+}\right)/\mathcal{B}\left({\Omega}_c^0\to {\Omega}^{-}{\pi}^{+}\right)=0.253\pm 0.052\left(\textrm{stat}.\right)\pm 0.030\left(\textrm{syst}.\right). $$ No significant signals of Ω c 0 → Ξ − K + $$ {\Omega}_c^0\to {\Xi}^{-}{K}^{+} $$ and Ω − K + modes are found. The upper limits at 90% confidence level on ratios of branching fractions are determined to be B Ω c 0 → Ξ − K + / B Ω c 0 → Ω − π + < 0.070 $$ \mathcal{B}\left({\Omega}_c^0\to {\Xi}^{-}{K}^{+}\right)/\mathcal{B}\left({\Omega}_c^0\to {\Omega}^{-}{\pi}^{+}\right)