Weak Radiative B-Meson Decay Beyond Leading Logarithms

Abstract

We present our results for three-loop anomalous dimensions necessary in analyzing $B{\to}X_sγ$ decay at the next-to-leading order in QCD. We combine them with other recently calculated contributions, obtaining a practically complete next-to-leading order prediction for the branching ratio ${\cal B}(B{\to}X_sγ) = (3.28 \pm 0.33) \times 10^{-4}$. The uncertainty is more than twice smaller than in the previously available leading order theoretical result. The Standard Model prediction remains in agreement with the CLEO measurement at the $2 σ$ level.