The rare decay b--> s gluon beyond leading logarithms

Abstract

We calculate the alpha_s virtual corrections to the decay width for b --> s gluon in the standard model. Also the corresponding order alpha_s bremsstrahlung corrections are systematically calculated in this paper. The combined result is free of infrared and collinear singularities, in accordance with the KLN theorem. Taking into account the existing next-to-leading logarithmic (NLL) result for the Wilson coefficient C_8^(eff), a complete NLL result for the branching ratio B(b -> s gluon) is derived. Numerically, we obtain B^(NLL)=(5.0 +/- 1.0) * 10^{-3}, which is more than a factor of two larger than the leading logarithmic result B^(LL)=(2.2 +/- 0.8) * 10^{-3}.