Work

QCD factorization for the $$B \rightarrow \gamma \ell \nu _{\ell }$$ decay beyond leading power

Year: 2025

Type: article

Abstract: The radiative leptonic $$B \rightarrow \gamma \ell \nu _{\ell }$$ 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 $$\Lambda _\textrm{QCD}/m_b$$ 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 $$B \rightarrow \gamma \ell \nu _{\ell }$$ 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.

Source: The European Physical Journal C

DOI: 10.1140/epjc/s10052-025-14772-z

Authors: Bo-Yan Cui, Yue-Long Shen, Chao Wang, Yan-Bing Wei