Numerical evaluation of two-loop QCD helicity amplitudes for gg → t t ¯ g $$ gg\to t\overline{t}g $$ at leading colour

Abstract We present the first benchmark evaluation of the two-loop finite remainders for the production of a top-quark pair in association with a jet at hadron colliders in the gluon channel. We work in the leading colour approximation, and perform the numerical evaluation in the physical phase spac...

Full description

Saved in:
Bibliographic Details
Main Authors: Simon Badger, Matteo Becchetti, Colomba Brancaccio, Heribertus Bayu Hartanto, Simone Zoia
Format: Article
Language:English
Published: SpringerOpen 2025-03-01
Series:Journal of High Energy Physics
Subjects:
Online Access:https://doi.org/10.1007/JHEP03(2025)070
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850201746449629184
author Simon Badger
Matteo Becchetti
Colomba Brancaccio
Heribertus Bayu Hartanto
Simone Zoia
author_facet Simon Badger
Matteo Becchetti
Colomba Brancaccio
Heribertus Bayu Hartanto
Simone Zoia
author_sort Simon Badger
collection DOAJ
description Abstract We present the first benchmark evaluation of the two-loop finite remainders for the production of a top-quark pair in association with a jet at hadron colliders in the gluon channel. We work in the leading colour approximation, and perform the numerical evaluation in the physical phase space. To achieve this result, we develop a new method for expressing the master integrals in terms of a (over-complete) basis of special functions that enables the infrared and ultraviolet poles to be cancelled analytically despite the presence of elliptic Feynman integrals. The special function basis makes it manifest that the elliptic functions appear solely in the finite remainder, and can be evaluated numerically through generalised series expansions. The helicity amplitudes are constructed using four dimensional projectors combined with finite-field techniques to perform integration-by-parts reduction, mapping to special functions and Laurent expansion in the dimensional regularisation parameter.
format Article
id doaj-art-7c93c5268a0a4e7eae4a2e834ac9b7fc
institution OA Journals
issn 1029-8479
language English
publishDate 2025-03-01
publisher SpringerOpen
record_format Article
series Journal of High Energy Physics
spelling doaj-art-7c93c5268a0a4e7eae4a2e834ac9b7fc2025-08-20T02:11:57ZengSpringerOpenJournal of High Energy Physics1029-84792025-03-012025313210.1007/JHEP03(2025)070Numerical evaluation of two-loop QCD helicity amplitudes for gg → t t ¯ g $$ gg\to t\overline{t}g $$ at leading colourSimon Badger0Matteo Becchetti1Colomba Brancaccio2Heribertus Bayu Hartanto3Simone Zoia4Dipartimento di Fisica and Arnold-Regge Center, Università di Torino, and INFN, Sezione di TorinoDipartimento di Fisica e Astronomia, Università di Bologna and INFN, Sezione di BolognaDipartimento di Fisica and Arnold-Regge Center, Università di Torino, and INFN, Sezione di TorinoAsia Pacific Center for Theoretical PhysicsPhysik-Institut, Universität ZürichAbstract We present the first benchmark evaluation of the two-loop finite remainders for the production of a top-quark pair in association with a jet at hadron colliders in the gluon channel. We work in the leading colour approximation, and perform the numerical evaluation in the physical phase space. To achieve this result, we develop a new method for expressing the master integrals in terms of a (over-complete) basis of special functions that enables the infrared and ultraviolet poles to be cancelled analytically despite the presence of elliptic Feynman integrals. The special function basis makes it manifest that the elliptic functions appear solely in the finite remainder, and can be evaluated numerically through generalised series expansions. The helicity amplitudes are constructed using four dimensional projectors combined with finite-field techniques to perform integration-by-parts reduction, mapping to special functions and Laurent expansion in the dimensional regularisation parameter.https://doi.org/10.1007/JHEP03(2025)070Higher-Order Perturbative CalculationsScattering AmplitudesTop Quark
spellingShingle Simon Badger
Matteo Becchetti
Colomba Brancaccio
Heribertus Bayu Hartanto
Simone Zoia
Numerical evaluation of two-loop QCD helicity amplitudes for gg → t t ¯ g $$ gg\to t\overline{t}g $$ at leading colour
Journal of High Energy Physics
Higher-Order Perturbative Calculations
Scattering Amplitudes
Top Quark
title Numerical evaluation of two-loop QCD helicity amplitudes for gg → t t ¯ g $$ gg\to t\overline{t}g $$ at leading colour
title_full Numerical evaluation of two-loop QCD helicity amplitudes for gg → t t ¯ g $$ gg\to t\overline{t}g $$ at leading colour
title_fullStr Numerical evaluation of two-loop QCD helicity amplitudes for gg → t t ¯ g $$ gg\to t\overline{t}g $$ at leading colour
title_full_unstemmed Numerical evaluation of two-loop QCD helicity amplitudes for gg → t t ¯ g $$ gg\to t\overline{t}g $$ at leading colour
title_short Numerical evaluation of two-loop QCD helicity amplitudes for gg → t t ¯ g $$ gg\to t\overline{t}g $$ at leading colour
title_sort numerical evaluation of two loop qcd helicity amplitudes for gg t t ¯ g gg to t overline t g at leading colour
topic Higher-Order Perturbative Calculations
Scattering Amplitudes
Top Quark
url https://doi.org/10.1007/JHEP03(2025)070
work_keys_str_mv AT simonbadger numericalevaluationoftwoloopqcdhelicityamplitudesforggttgggtotoverlinetgatleadingcolour
AT matteobecchetti numericalevaluationoftwoloopqcdhelicityamplitudesforggttgggtotoverlinetgatleadingcolour
AT colombabrancaccio numericalevaluationoftwoloopqcdhelicityamplitudesforggttgggtotoverlinetgatleadingcolour
AT heribertusbayuhartanto numericalevaluationoftwoloopqcdhelicityamplitudesforggttgggtotoverlinetgatleadingcolour
AT simonezoia numericalevaluationoftwoloopqcdhelicityamplitudesforggttgggtotoverlinetgatleadingcolour