Observation of radiative B⁰ -> ϕK⁰ γdecays

2009/11/09 by Adachi, I.
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex)

paper · doi:10.48550/arxiv.0911.1779

Abstract

We report the first observation of radiative decay B⁰ -> ϕK⁰ γusing a data sample of 772x10⁶ BBar pairs collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We observe a signal of 35+/-8 events with a significance of 5.4 standard deviations including systematic uncertainties. The measured branching fraction is \cal B(B⁰ -> ϕK⁰ γ) = (2.66± 0.60 ± 0.32) × 10^-6. We also precisely measure \cal B(B⁺ -> ϕK⁺ γ) = (2.34± 0.29 ± 0.23) × 10^-6. The uncertainties are statistical and systematic, respectively. The observed M_ϕK mass spectrum differs significantly from that expected in a three-body phase-space decay.

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