Local infrared safety in time-ordered perturbation theory

Fuente: arXiv
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Main Authors: Sterman, George, Venkata, Aniruddha
Format: Preprint
Published: 2023
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author Sterman, George
Venkata, Aniruddha
author_facet Sterman, George
Venkata, Aniruddha
contents We develop a general expression for weighted cross sections in leptonic annihilation to hadrons based on time-ordered perturbation theory (TOPT). The analytic behavior of the resulting integrals over spatial momenta can be analyzed in the language of Landau equations and infrared (IR) power counting. For any infrared-safe weight, the cancellation of infrared divergences is implemented locally at the integrand level, and in principle can be evaluated numerically in four dimensions. We go on to show that it is possible to eliminate unphysical singularities that appear in time-ordered perturbation theory for arbitrary amplitudes. This is done by reorganizing TOPT into an equivalent form that combines classes of time orderings into a ``partially time-ordered perturbation theory". Applying the formalism to leptonic annihilation, we show how to derive diagrammatic expressions with only physical unitarity cuts.
format Preprint
id arxiv_https___arxiv_org_abs_2309_13023
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Local infrared safety in time-ordered perturbation theory
Sterman, George
Venkata, Aniruddha
High Energy Physics - Phenomenology
We develop a general expression for weighted cross sections in leptonic annihilation to hadrons based on time-ordered perturbation theory (TOPT). The analytic behavior of the resulting integrals over spatial momenta can be analyzed in the language of Landau equations and infrared (IR) power counting. For any infrared-safe weight, the cancellation of infrared divergences is implemented locally at the integrand level, and in principle can be evaluated numerically in four dimensions. We go on to show that it is possible to eliminate unphysical singularities that appear in time-ordered perturbation theory for arbitrary amplitudes. This is done by reorganizing TOPT into an equivalent form that combines classes of time orderings into a ``partially time-ordered perturbation theory". Applying the formalism to leptonic annihilation, we show how to derive diagrammatic expressions with only physical unitarity cuts.
title Local infrared safety in time-ordered perturbation theory
topic High Energy Physics - Phenomenology
url https://arxiv.org/abs/2309.13023