Measurements of the branching fractions of Ξ0c→ΛK0S, Ξ0c→Σ0K0S, and Ξ0c→Σ+K− decays at Belle

Abstract

[EN] Using the entire data sample of 980 fb(-1) collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider, we present measurements of the branching fractions of the Cabibbo-favored decays Xi c(0) -> Lambda K-S(0), Xi(0)(c) ->Sigma K-0(S)0, and Xi c(0) -> Sigma K-+(-). Taking the decay Xi c(0) -> Xi(-)pi(+) as the normalization mode, we measure the branching fraction ratio B(Xi(0)(c) -> Lambda K-S(0))=B(Xi(0)(c) -> Xi(-)pi(+)) = 0.229 + 0.008 + 0.012 with improved precision, and measure the branching fraction ratios B(Xi 0c -> Sigma K-0(S)0)=B(Xi(0)(c) -> Xi(-)pi(+)) = 0.038 + 0.006 + 0.004 and B(Xi(0)(c) -> Sigma K-+(-))=B(Xi(0)(c) -> Xi(-)pi(+)) = 0.123 + 0.007 + 0.010 for the first time. Taking into account the branching fraction of the normalization mode, the absolute branching fractions are determined to be B(Xi(0)(c) -> Lambda K-S(0)) = (3.27 + 0.11 + 0.17 + 0.73) x 10(-3), B(Xi(0)(c) -> Sigma K-0(S)0) = (0.54 + 0.09 + 0.06 +0.12) x 10(-3), and B(Xi(0)(c) -> Sigma K-+(-)) = (1.76 + 0.10 + 0.14 + 0.39) x 10(-3). The first and second uncer-tainties above are statistical and systematic, respectively, while the third ones arise from the uncertainty of the branching fraction of Xi(0)(c) -> Xi(-)pi(+).