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Main Authors: Mishnyakov, Victor, Morozov, Alexei, Suprun, Pavel
Format: Preprint
Published: 2023
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Online Access:https://arxiv.org/abs/2303.08851
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author Mishnyakov, Victor
Morozov, Alexei
Suprun, Pavel
author_facet Mishnyakov, Victor
Morozov, Alexei
Suprun, Pavel
contents The answers for Feynman diagrams satisfy various kinds of differential equations -- which is not a surprise, because they are defined as Gaussian correlators, possessing a vast variety of Ward identities and superintegrability properties. We study these equations in the simplest example of banana diagrams. They contain any number of loops, but can be efficiently handled in position rather than momentum representation, where loop integrals do not show up. We derive equations for the case of scalar fields, explain their origins and drastic simplification at coincident masses. To further simplify the story we do not consider coincident points, i.e. ignore delta-function contributions and ultraviolet divergences for the most part. The equations in this case reduce to homogeneous and have as many solutions as there are different Green functions -- $2^n$ for $n$ loops in quadratic theory, what reduces to just $n+1$ for coincident masses, i.e. for a single field. We comment on the recovery of the delta-functions directly from the homogeneous equations and also compare our result with momentum space formulas known in the literature.
format Preprint
id arxiv_https___arxiv_org_abs_2303_08851
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Position Space Equations for Banana Feynman Diagrams
Mishnyakov, Victor
Morozov, Alexei
Suprun, Pavel
High Energy Physics - Theory
Mathematical Physics
The answers for Feynman diagrams satisfy various kinds of differential equations -- which is not a surprise, because they are defined as Gaussian correlators, possessing a vast variety of Ward identities and superintegrability properties. We study these equations in the simplest example of banana diagrams. They contain any number of loops, but can be efficiently handled in position rather than momentum representation, where loop integrals do not show up. We derive equations for the case of scalar fields, explain their origins and drastic simplification at coincident masses. To further simplify the story we do not consider coincident points, i.e. ignore delta-function contributions and ultraviolet divergences for the most part. The equations in this case reduce to homogeneous and have as many solutions as there are different Green functions -- $2^n$ for $n$ loops in quadratic theory, what reduces to just $n+1$ for coincident masses, i.e. for a single field. We comment on the recovery of the delta-functions directly from the homogeneous equations and also compare our result with momentum space formulas known in the literature.
title Position Space Equations for Banana Feynman Diagrams
topic High Energy Physics - Theory
Mathematical Physics
url https://arxiv.org/abs/2303.08851