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Title: Local infrared safety in time-ordered perturbation theory
A<sc>bstract</sc> 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.  more » « less
Award ID(s):
2210533
PAR ID:
10504765
Author(s) / Creator(s):
;
Publisher / Repository:
JHEP
Date Published:
Journal Name:
Journal of High Energy Physics
Volume:
2024
Issue:
2
ISSN:
1029-8479
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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