First observation of Cabibbo-suppressed Ξc0 decays

Abstract

We report the first observation of the Cabibbo-suppressed decays Ξc0→Ξ-K+, Ξc0→ΛK +K- and Ξc0→Λφ, using a data sample of 711 fb-1 collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We measure the ratios of branching fractions to be B(Ξc0→Ξ -K+)B(Ξc0→Ξ-π+)=(2. 75±0.51±0.25)×10-2, B(Ξc0→ΛK +K-)B(Ξc0→Ξ-π+)=(2. 86±0.61±0.37)×10-2 and B(Ξc0→Λ φ)B(Ξc0→Ξ-π+)=(3.43±0. 58±0.32)×10-2, where the first uncertainty is statistical and the second is systematic. © 2013 American Physical Society.