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arXiv · 0709.4422

Towards $B \to V γ$ Decays at NNLO in SCET

Ahmed Ali·Ben D. Pecjak·Christoph Greub
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Abstract

We compute NNLO (${\cal O}(α_s^2)$) corrections to the hard-scattering kernels entering the QCD factorization formula for $B\to Vγ$ 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 $B\to K^*γ$ and $B_s\to ϕγ$ decays at NNLO and compare them with the current experimental data.

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Ahmed Ali, Ben D. Pecjak, Christoph Greub. 2008-04-17. Towards $B \to V γ$ Decays at NNLO in SCET. https://doi.org/10.1140/epjc%2Fs10052-008-0623-5

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