General finite two-loop amplitude integrand for photoproduction in quark annihilation

Fuente: arXiv
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Auteurs principaux: Anastasiou, Charalampos, Karlen, Julia, Sahoo, Roshni, Sterman, George, Vicini, Matilde
Format: Preprint
Publié: 2025
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author Anastasiou, Charalampos
Karlen, Julia
Sahoo, Roshni
Sterman, George
Vicini, Matilde
author_facet Anastasiou, Charalampos
Karlen, Julia
Sahoo, Roshni
Sterman, George
Vicini, Matilde
contents The construction of integrands free of infrared and ultraviolet singularities may enable the application of numerical methods to evaluate loop amplitudes that are inaccessible with analytic techniques. At two loops, finite amplitude integrands have been constructed for the production of off-shell or massive colorless particles via quark annihilation. In this article, we extend this class of processes to include real photons in the final state. To achieve this, we introduce appropriate momentum flows and counterterms to eliminate singularities that occur because the photons are massless. These singularities arise only locally at the integrand level and do not lead to divergences upon integration. Our treatment also eliminates all power singularities arising from self-energy corrections in the integrand. We extend the analysis to gluon emission from virtual quarks. We believe these new insights will be useful for future extensions of infrared subtraction methods to processes with final-state jets.
format Preprint
id arxiv_https___arxiv_org_abs_2509_07805
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle General finite two-loop amplitude integrand for photoproduction in quark annihilation
Anastasiou, Charalampos
Karlen, Julia
Sahoo, Roshni
Sterman, George
Vicini, Matilde
High Energy Physics - Phenomenology
High Energy Physics - Theory
The construction of integrands free of infrared and ultraviolet singularities may enable the application of numerical methods to evaluate loop amplitudes that are inaccessible with analytic techniques. At two loops, finite amplitude integrands have been constructed for the production of off-shell or massive colorless particles via quark annihilation. In this article, we extend this class of processes to include real photons in the final state. To achieve this, we introduce appropriate momentum flows and counterterms to eliminate singularities that occur because the photons are massless. These singularities arise only locally at the integrand level and do not lead to divergences upon integration. Our treatment also eliminates all power singularities arising from self-energy corrections in the integrand. We extend the analysis to gluon emission from virtual quarks. We believe these new insights will be useful for future extensions of infrared subtraction methods to processes with final-state jets.
title General finite two-loop amplitude integrand for photoproduction in quark annihilation
topic High Energy Physics - Phenomenology
High Energy Physics - Theory
url https://arxiv.org/abs/2509.07805