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Main Author: Correia, Miguel
Format: Preprint
Published: 2022
Subjects:
Online Access:https://arxiv.org/abs/2212.06157
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author Correia, Miguel
author_facet Correia, Miguel
contents Feynman diagrams (notably the triangle diagram) involving heavy enough particles contain branch cuts on the physical sheet - anomalous thresholds - which, unlike normal thresholds and bound-state poles, do not correspond to any asymptotic $n$-particle state. ``Who ordered that?" We show that anomalous thresholds arise as a consequence of established S-matrix principles and two reasonable assumptions: unitarity below the physical region and analyticity in the mass. We find explicit nonperturbative formulas for the anomalous threshold singularity and test them against the Coleman-Thun poles of the exactly solvable $E_8$ integrable model.
format Preprint
id arxiv_https___arxiv_org_abs_2212_06157
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Nonperturbative Anomalous Thresholds
Correia, Miguel
High Energy Physics - Theory
High Energy Physics - Phenomenology
Feynman diagrams (notably the triangle diagram) involving heavy enough particles contain branch cuts on the physical sheet - anomalous thresholds - which, unlike normal thresholds and bound-state poles, do not correspond to any asymptotic $n$-particle state. ``Who ordered that?" We show that anomalous thresholds arise as a consequence of established S-matrix principles and two reasonable assumptions: unitarity below the physical region and analyticity in the mass. We find explicit nonperturbative formulas for the anomalous threshold singularity and test them against the Coleman-Thun poles of the exactly solvable $E_8$ integrable model.
title Nonperturbative Anomalous Thresholds
topic High Energy Physics - Theory
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2212.06157