Measurements of the branching fractions of Ξ 0 c → Λ K 0 S , Ξ 0 c → Σ 0 K 0 S , and Ξ 0 c → Σ + K − decays at Belle

Abstract

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 Ξ 0 c → Λ K 0 S , Ξ 0 c → Σ 0 K 0 S , and Ξ 0 c → Σ + K − . Taking the decay Ξ 0 c → Ξ − π + as the normalization mode, we measure the branching fraction ratio B ( Ξ 0 c → Λ K 0 S ) / B ( Ξ 0 c → Ξ − π + ) = 0.229 ± 0.008 ± 0.012 with improved precision, and measure the branching fraction ratios B ( Ξ 0 c → Σ 0 K 0 S ) / B ( Ξ 0 c → Ξ − π + ) = 0.038 ± 0.006 ± 0.004 and B ( Ξ 0 c → Σ + K − ) / B ( Ξ 0 c → Ξ − π + ) = 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 ( Ξ 0 c → Λ K 0 S ) = ( 3.27 ± 0.11 ± 0.17 ± 0.73 ) × 10 − 3 , B ( Ξ 0 c → Σ 0 K 0 S ) = ( 0.54 ± 0.09 ± 0.06 ± 0.12 ) × 10 − 3 , and B ( Ξ 0 c → Σ + K − ) = ( 1.76 ± 0.10 ± 0.14 ± 0.39 ) × 10 − 3 . The first and second uncertainties above are statistical and systematic, respectively, while the third ones arise from the uncertainty of the branching fraction of Ξ 0 c → Ξ − π + .