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arXiv · 2212.14430

Structure-Dependent QED Effects in Exclusive B Decays at Subleading Power

Claudia Cornella·Matthias König·Matthias Neubert
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Abstract

We derive a factorization theorem for the structure-dependent QED effects in the weak exclusive process $B^-\to\ell^-\bar\nu_\ell$, i.e., effects probing the internal structure of the $B$ meson. The derivation requires a careful treatment of endpoint-divergent convolutions common to subleading-power factorization formulas. We find that the decay amplitude is sensitive to two- and three-particle light-cone distribution amplitudes of the $B$ meson as well as to a new hadronic parameter $F(\mu,\Lambda)$, which generalizes the notion of the $B$-meson decay constant in the presence of QED effects. This is the first derivation of a subleading-power factorization theorem in which the soft functions are non-perturbative hadronic matrix elements.

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Claudia Cornella, Matthias König, Matthias Neubert. 2022-12-29. Structure-Dependent QED Effects in Exclusive B Decays at Subleading Power. https://doi.org/10.1103/physrevd.108.l031502

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