Symmetry properties of Wilson loops with a Lagrangian insertion

Abstract Null Wilson loops in N $$ \mathcal{N} $$ = 4 super Yang-Mills are dual to planar scattering amplitudes. This duality implies hidden symmetries for both objects. We consider closely related infrared finite observables, defined as the Wilson loop with a Lagrangian insertion, normalized by the...

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Main Authors: Dmitry Chicherin, Johannes M. Henn
Format: Article
Language:English
Published: SpringerOpen 2022-07-01
Series:Journal of High Energy Physics
Subjects:
Online Access:https://doi.org/10.1007/JHEP07(2022)057
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author Dmitry Chicherin
Johannes M. Henn
author_facet Dmitry Chicherin
Johannes M. Henn
author_sort Dmitry Chicherin
collection DOAJ
description Abstract Null Wilson loops in N $$ \mathcal{N} $$ = 4 super Yang-Mills are dual to planar scattering amplitudes. This duality implies hidden symmetries for both objects. We consider closely related infrared finite observables, defined as the Wilson loop with a Lagrangian insertion, normalized by the Wilson loop itself. Unlike ratio and remainder functions studied in the literature, this observable is non-trivial already for four scattered particles and bears close resemblance to (finite parts of) scattering processes in non-supersymmetric Yang-Mills theory. Moreover, by integrating over the insertion point, one can recover information on the amplitude, as was recently done to compute the full four-loop cusp anomalous dimension. We study the general structure of the Wilson loop with a Lagrangian insertion, focusing in particular on its leading singularities and their (hidden) symmetry properties. Thanks to the close connection of the observable to integrands of MHV amplitudes, it is natural to expect that its leading singularities can be written as certain Grassmannian integrals. The latter are manifestly dual conformal. They also have a conformal symmetry, up to total derivatives. We find that, surprisingly, the conformal symmetry becomes an invariance in the frame where the Lagrangian insertion point is sent to infinity. Furthermore, we use integrability methods to study how higher Yangian charges act on the Grassmannian integral. We evaluate the n-particle observable both at tree- and at one-loop level, finding compact analytic formulas. These results are explicitly written in the form of conformal leading singularities, multiplied by transcendental functions. We then compare these formulas to known expressions for all-plus amplitudes in pure Yang-Mills theory. We find a remarkable new connection: the Wilson loop with Lagrangian insertion in N $$ \mathcal{N} $$ = 4 super Yang-Mills appears to predict the maximal weight terms of the planar pure Yang-Mills all-plus amplitude. We test this relationship for the two-loop n-point Yang-Mills amplitude, as well as for the three-loop four-point amplitude.
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spelling doaj.art-9723afdbe72f413092d1a0e694f4575e2022-12-22T03:01:12ZengSpringerOpenJournal of High Energy Physics1029-84792022-07-012022715310.1007/JHEP07(2022)057Symmetry properties of Wilson loops with a Lagrangian insertionDmitry Chicherin0Johannes M. Henn1LAPTh, Université Savoie Mont Blanc, CNRSMax-Planck-Institut für Physik, Werner-Heisenberg-InstitutAbstract Null Wilson loops in N $$ \mathcal{N} $$ = 4 super Yang-Mills are dual to planar scattering amplitudes. This duality implies hidden symmetries for both objects. We consider closely related infrared finite observables, defined as the Wilson loop with a Lagrangian insertion, normalized by the Wilson loop itself. Unlike ratio and remainder functions studied in the literature, this observable is non-trivial already for four scattered particles and bears close resemblance to (finite parts of) scattering processes in non-supersymmetric Yang-Mills theory. Moreover, by integrating over the insertion point, one can recover information on the amplitude, as was recently done to compute the full four-loop cusp anomalous dimension. We study the general structure of the Wilson loop with a Lagrangian insertion, focusing in particular on its leading singularities and their (hidden) symmetry properties. Thanks to the close connection of the observable to integrands of MHV amplitudes, it is natural to expect that its leading singularities can be written as certain Grassmannian integrals. The latter are manifestly dual conformal. They also have a conformal symmetry, up to total derivatives. We find that, surprisingly, the conformal symmetry becomes an invariance in the frame where the Lagrangian insertion point is sent to infinity. Furthermore, we use integrability methods to study how higher Yangian charges act on the Grassmannian integral. We evaluate the n-particle observable both at tree- and at one-loop level, finding compact analytic formulas. These results are explicitly written in the form of conformal leading singularities, multiplied by transcendental functions. We then compare these formulas to known expressions for all-plus amplitudes in pure Yang-Mills theory. We find a remarkable new connection: the Wilson loop with Lagrangian insertion in N $$ \mathcal{N} $$ = 4 super Yang-Mills appears to predict the maximal weight terms of the planar pure Yang-Mills all-plus amplitude. We test this relationship for the two-loop n-point Yang-Mills amplitude, as well as for the three-loop four-point amplitude.https://doi.org/10.1007/JHEP07(2022)057Scattering AmplitudesWilson’t Hooft and Polyakov loops
spellingShingle Dmitry Chicherin
Johannes M. Henn
Symmetry properties of Wilson loops with a Lagrangian insertion
Journal of High Energy Physics
Scattering Amplitudes
Wilson
’t Hooft and Polyakov loops
title Symmetry properties of Wilson loops with a Lagrangian insertion
title_full Symmetry properties of Wilson loops with a Lagrangian insertion
title_fullStr Symmetry properties of Wilson loops with a Lagrangian insertion
title_full_unstemmed Symmetry properties of Wilson loops with a Lagrangian insertion
title_short Symmetry properties of Wilson loops with a Lagrangian insertion
title_sort symmetry properties of wilson loops with a lagrangian insertion
topic Scattering Amplitudes
Wilson
’t Hooft and Polyakov loops
url https://doi.org/10.1007/JHEP07(2022)057
work_keys_str_mv AT dmitrychicherin symmetrypropertiesofwilsonloopswithalagrangianinsertion
AT johannesmhenn symmetrypropertiesofwilsonloopswithalagrangianinsertion