The LBK theorem to all orders

Abstract We study the soft limit of one-photon radiation at next-to-leading power (NLP) in the framework of heavy-quark effective theory (HQET) to all orders in perturbation theory. We establish the soft theorem that for unpolarised scattering the radiative contribution up to NLP is entirely determi...

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Main Author: Tim Engel
Format: Article
Language:English
Published: SpringerOpen 2023-07-01
Series:Journal of High Energy Physics
Subjects:
Online Access:https://doi.org/10.1007/JHEP07(2023)177
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author Tim Engel
author_facet Tim Engel
author_sort Tim Engel
collection DOAJ
description Abstract We study the soft limit of one-photon radiation at next-to-leading power (NLP) in the framework of heavy-quark effective theory (HQET) to all orders in perturbation theory. We establish the soft theorem that for unpolarised scattering the radiative contribution up to NLP is entirely determined by the non-radiative amplitude. This generalises the Low-Burnett-Kroll (LBK) theorem for QED to all orders. All hard matching corrections can be calculated by applying the LBK differential operator to the non-radiative amplitude. The virtual corrections in the effective theory vanish beyond one loop, resulting in a one-loop exact soft function. As a first, non-trivial application we calculate the real-virtual-virtual electron-line corrections to muon-electron scattering at NLP in the soft limit.
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spelling doaj.art-a2108070f93b49ac9579bb4a7c5096472023-10-29T12:06:44ZengSpringerOpenJournal of High Energy Physics1029-84792023-07-012023713210.1007/JHEP07(2023)177The LBK theorem to all ordersTim Engel0Physikalisches Institut, Albert-Ludwigs-Universität FreiburgAbstract We study the soft limit of one-photon radiation at next-to-leading power (NLP) in the framework of heavy-quark effective theory (HQET) to all orders in perturbation theory. We establish the soft theorem that for unpolarised scattering the radiative contribution up to NLP is entirely determined by the non-radiative amplitude. This generalises the Low-Burnett-Kroll (LBK) theorem for QED to all orders. All hard matching corrections can be calculated by applying the LBK differential operator to the non-radiative amplitude. The virtual corrections in the effective theory vanish beyond one loop, resulting in a one-loop exact soft function. As a first, non-trivial application we calculate the real-virtual-virtual electron-line corrections to muon-electron scattering at NLP in the soft limit.https://doi.org/10.1007/JHEP07(2023)177Effective Field TheoriesPrecision QEDScattering Amplitudes
spellingShingle Tim Engel
The LBK theorem to all orders
Journal of High Energy Physics
Effective Field Theories
Precision QED
Scattering Amplitudes
title The LBK theorem to all orders
title_full The LBK theorem to all orders
title_fullStr The LBK theorem to all orders
title_full_unstemmed The LBK theorem to all orders
title_short The LBK theorem to all orders
title_sort lbk theorem to all orders
topic Effective Field Theories
Precision QED
Scattering Amplitudes
url https://doi.org/10.1007/JHEP07(2023)177
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