Evidence for the singly Cabibbo-suppressed decay Ωc0→Ξ−π+ and search for Ωc0→Ξ−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 Ωc0→Ξ−π+ and Ω−K+ and the doubly Cabibbo-suppressed decay Ωc0→Ξ−K+. Evidence for an Ωc0 signal in the Ωc0→ Ξ−π+ mode is reported with a significance of 4.5σ including systematic uncertainties. The ratio of branching fractions to the normalization mode Ωc0→ Ω−π+ is measured to beB(Ωc0→Ξ−π+)/B(Ωc0→Ω−π+)=0.253±0.052(stat.)±0.030(syst.). No significant signals of Ωc0→Ξ−K+ and Ω−K+ modes are found. The upper limits at 90% confidence level on ratios of branching fractions are determined to beB(Ωc0→Ξ−K+)/B(Ωc0→Ω−π+)<0.070 andB(Ωc0→Ω−K+)/B(Ωc0→Ω−π+)<0.29. [Figure not available: see fulltext.].