QCD factorization for the B → γ ν decay beyond leading power

The radiative leptonic B → γ ν B → γ ℓ ν ℓ decay serves as an ideal platform to determine the B -meson inverse moment which is a fundamental nonperturbative parameter for the B meson. In this paper, we explore precise QCD contributions to this decay with an energetic photon. We reproduce the next-to-next-to-leading-logarithmic resummation formula for the decay amplitude at leading power in Λ QCD/mb Λ QCD / m b . Employing operator identities, we calculate subleading-power contributions from the expansion of the hard-collinear propagator of the internal up quark and the heavy-quark expansion of the bottom quark. We update the contributions from the hadronic structure of the photon to the B → γ ν B → γ ℓ ν ℓ process with the dispersion technique. Together with other yet known power corrections, phenomenological applications including the partial branching fraction and ratio of the branching fractions of the radiative B decay are investigated.