The soft quark Sudakov

Abstract There has been recent interest in understanding the all loop structure of the subleading power soft and collinear limits, with the goal of achieving a systematic resummation of subleading power infrared logarithms. Most of this work has focused on subleading power correctio...

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Main Authors: Moult, Ian, Stewart, Iain W, Vita, Gherardo, Zhu, Hua X
Other Authors: Massachusetts Institute of Technology. Center for Theoretical Physics
Format: Article
Language:English
Published: Springer Berlin Heidelberg 2021
Online Access:https://hdl.handle.net/1721.1/131712
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author Moult, Ian
Stewart, Iain W
Vita, Gherardo
Zhu, Hua X
author2 Massachusetts Institute of Technology. Center for Theoretical Physics
author_facet Massachusetts Institute of Technology. Center for Theoretical Physics
Moult, Ian
Stewart, Iain W
Vita, Gherardo
Zhu, Hua X
author_sort Moult, Ian
collection MIT
description Abstract There has been recent interest in understanding the all loop structure of the subleading power soft and collinear limits, with the goal of achieving a systematic resummation of subleading power infrared logarithms. Most of this work has focused on subleading power corrections to soft gluon emission, whose form is strongly constrained by symmetries. In this paper we initiate a study of the all loop structure of soft fermion emission. In N $$ \mathcal{N} $$ = 1 QCD we perform an operator based factorization and resummation of the associated infrared logarithms using the formalism introduced in [1], and prove that they exponentiate into a Sudakov due to their relation to soft gluon emission. We verify this result through explicit calculation to O α s 3 $$ \mathcal{O}\left({\alpha}_s^3\right) $$ . We show that in QCD, this simple Sudakov exponentiation is violated by endpoint contributions proportional to (CA−CF)n which contribute at leading logarithmic order. Combining our N $$ \mathcal{N} $$ = 1 result and our calculation of the endpoint contributions to O α s 3 $$ \mathcal{O}\left({\alpha}_s^3\right) $$ , we conjecture a result for the soft quark Sudakov in QCD, a new all orders function first appearing at subleading power, and give evidence for its universality. Our result, which is expressed in terms of combinations of cusp anomalous dimensions in different color representations, takes an intriguingly simple form and also exhibits interesting similarities to results for large-x logarithms in the off diagonal splitting functions.
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spelling mit-1721.1/1317122023-11-07T19:40:40Z The soft quark Sudakov Moult, Ian Stewart, Iain W Vita, Gherardo Zhu, Hua X Massachusetts Institute of Technology. Center for Theoretical Physics Abstract There has been recent interest in understanding the all loop structure of the subleading power soft and collinear limits, with the goal of achieving a systematic resummation of subleading power infrared logarithms. Most of this work has focused on subleading power corrections to soft gluon emission, whose form is strongly constrained by symmetries. In this paper we initiate a study of the all loop structure of soft fermion emission. In N $$ \mathcal{N} $$ = 1 QCD we perform an operator based factorization and resummation of the associated infrared logarithms using the formalism introduced in [1], and prove that they exponentiate into a Sudakov due to their relation to soft gluon emission. We verify this result through explicit calculation to O α s 3 $$ \mathcal{O}\left({\alpha}_s^3\right) $$ . We show that in QCD, this simple Sudakov exponentiation is violated by endpoint contributions proportional to (CA−CF)n which contribute at leading logarithmic order. Combining our N $$ \mathcal{N} $$ = 1 result and our calculation of the endpoint contributions to O α s 3 $$ \mathcal{O}\left({\alpha}_s^3\right) $$ , we conjecture a result for the soft quark Sudakov in QCD, a new all orders function first appearing at subleading power, and give evidence for its universality. Our result, which is expressed in terms of combinations of cusp anomalous dimensions in different color representations, takes an intriguingly simple form and also exhibits interesting similarities to results for large-x logarithms in the off diagonal splitting functions. 2021-09-20T17:29:51Z 2021-09-20T17:29:51Z 2020-05-20 2020-06-26T13:24:51Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/131712 Journal of High Energy Physics. 2020 May 20;2020(5):89 PUBLISHER_CC en https://doi.org/10.1007/JHEP05(2020)089 Creative Commons Attribution https://creativecommons.org/licenses/by/4.0/ The Author(s) application/pdf Springer Berlin Heidelberg Springer Berlin Heidelberg
spellingShingle Moult, Ian
Stewart, Iain W
Vita, Gherardo
Zhu, Hua X
The soft quark Sudakov
title The soft quark Sudakov
title_full The soft quark Sudakov
title_fullStr The soft quark Sudakov
title_full_unstemmed The soft quark Sudakov
title_short The soft quark Sudakov
title_sort soft quark sudakov
url https://hdl.handle.net/1721.1/131712
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