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Ali, A.; Pecjak, B.D.; Greub, C.
European physical journal. C, Particles and fields, 06/2008, Letnik: 55, Številka: 4Journal Article
We compute NNLO ( (α s 2 )) corrections to the hard-scattering kernels entering the QCD factorization formula for B→Vγ decays, where V is a light vector meson. We give complete NNLO results for the dipole operators Q 7 and Q 8 , and partial results for Q 1 valid in the large-β 0 limit and neglecting the NNLO correction from hard-spectator scattering. Large perturbative logarithms in the hard-scattering kernels are identified and resummed using soft-collinear effective theory. We use our results to estimate the branching fractions for B→K * γ and B s →φγ decays at NNLO and compare them with the current experimental data.
