Measurement of the resonant and nonresonant branching ratios in Ξc0 → Ξ0K+K-

Using the entire data sample of 980 fb-1 integrated luminosity collected with the Belle detector at the KEKB asymmetric-energy e+e- collider, we present an amplitude analysis measuring the branching fractions of the Cabibbo-allowed, W-exchange resonant decay Ξc0→Ξ0φ(→K+K-) with a polarized φ and the nonresonant decay via a direct process Ξc0→Ξ0K+K-. We present these measurements, relative to the normalization mode Ξ-π+, and find branching ratios B(Ξc0→Ξ0φ(→K+K-))(BΞc0→Ξ-π+)=0.036±0.004(stat.)±0.002(syst.) and B(Ξc0→Ξ0K+K-)B(Ξc0→Ξ-π+)=0.039±0.004(stat.)±0.002(syst.), which suggest that only minor cusping peaks occur in the combinatorial background of ω∗-→Ξ0K- due to these Ξc0 decays.