Analysis of Br(B-->Xs gamma) at NNLO with a Cut on Photon Energy
Abstract
By combining a recent estimate of the total B-->Xs gamma branching fraction at O(alphas2) with a detailed analysis of the effects of a cut Egamma>1.6GeV on photon energy, a prediction for the partial B-->Xs gamma branching fraction at next-to-next-to-leading order in renormalization-group improved perturbation theory is obtained, in which contributions from all relevant scales are properly factorized. The result Br(B-->Xs gamma)=(2.98+-0.26)x10-4 is about 1.4 sigma lower than the experimental world average. This opens a window for significant New Physics contributions in rare radiative B decays.
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