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Related papers: Analytic all-plus-helicity gluon amplitudes in QCD

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We combine the unitarity method with the six-dimensional helicity formalism of Cheung and O'Connell to construct loop-level scattering amplitudes. As a first example, we construct dimensionally regularized QCD one-loop four-point…

High Energy Physics - Theory · Physics 2015-03-17 Zvi Bern , John Joseph Carrasco , Tristan Dennen , Yu-tin Huang , Harald Ita

We present the two-loop amplitudes for a self-dual Higgs boson with up to four positive helicity gluons in the heavy top-quark limit. Because the tree amplitudes in the all-plus sector vanish, we can construct simple representations of the…

High Energy Physics - Phenomenology · Physics 2026-05-15 Simon Badger , Christian Biello , Colomba Brancaccio , Federico Ripani

Two-loop four-gluon N=4 susy amplitudes are evaluated via cutting techniques as a testing ground for QCD. A conjecture for four-point amplitudes to all loop orders is described. We also present a new conjecture for the leading-color part of…

High Energy Physics - Phenomenology · Physics 2009-10-30 Z. Bern , J. Rozowsky , B. Yan

We present a new method for computing complete one-loop amplitudes, including their rational parts, in non-supersymmetric gauge theory. This method merges the unitarity method with on-shell recursion relations. It systematizes a…

High Energy Physics - Phenomenology · Physics 2010-11-15 Zvi Bern , Lance J. Dixon , David A. Kosower

We present a computer library for the numerical evaluation of colour-ordered n-gluon amplitudes at one-loop order in pure Yang-Mills theory. The library uses the recently developed technique of generalised unitarity. Running in double…

High Energy Physics - Phenomenology · Physics 2013-03-05 Simon Badger , Benedikt Biedermann , Peter Uwer

We present an explicit expression for a particular $n$-gluon two loop scattering partial amplitude. Specifically we present an analytic form for the single trace $N_c$ independent colour partial amplitude for the case where all external…

High Energy Physics - Phenomenology · Physics 2020-04-08 David C. Dunbar , Warren B. Perkins , Joseph M. W. Strong

We present the first numerical computation of two-loop amplitudes based on the unitarity method. As a proof of principle, we compute the four-gluon process. We discuss the new method, analyze its numerical properties and apply it to…

High Energy Physics - Phenomenology · Physics 2017-10-11 S. Abreu , F. Febres Cordero , H. Ita , M. Jaquier , B. Page , M. Zeng

We present a calculation of the rational terms in two-loop all-plus gluon amplitudes using $D$-dimensional unitarity. We use a conjecture of separability of the two loops, and then a simple generalization of one-loop $D$-dimensional…

High Energy Physics - Phenomenology · Physics 2022-06-30 David A. Kosower , Sebastian Pögel

We compute the two-loop helicity amplitudes for the production of three photons at hadron colliders in QCD at leading-color. Using the two-loop numerical unitarity method coupled with analytic reconstruction techniques, we obtain the…

High Energy Physics - Phenomenology · Physics 2021-01-20 S. Abreu , B. Page , E. Pascual , V. Sotnikov

All positive helicity four-point gluon-graviton amplitudes in Einstein-Yang-Mills theory coupled to a dilaton and axion field are computed at the leading one-loop order using colour-kinematics duality. In particular, all relevant…

High Energy Physics - Theory · Physics 2019-02-20 Josua Faller , Jan Plefka

We compute the helicity amplitudes for the processes $gg\to Zg$ and $gg\to Z\gamma$ to two loops in massless QCD. The perturbative expansion of these processes starts only at the one-loop level, such that our results are a crucial…

High Energy Physics - Phenomenology · Physics 2023-08-21 Thomas Gehrmann , Lorenzo Tancredi , Erich Weihs

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…

High Energy Physics - Phenomenology · Physics 2025-03-14 Simon Badger , Matteo Becchetti , Colomba Brancaccio , Heribertus Bayu Hartanto , Simone Zoia

We compute a complete set of independent leading-color two-loop five-parton amplitudes in QCD. These constitute a fundamental ingredient for the next-to-next-to-leading order QCD corrections to three-jet production at hadron colliders. We…

High Energy Physics - Phenomenology · Physics 2019-04-09 S. Abreu , F. Febres Cordero , H. Ita , B. Page , V. Sotnikov

We present the master integrals relevant for computing the complete set of leading-colour analytic helicity amplitudes for top-quark pair production via gluon fusion at two-loops in QCD. We include corrections due to massive fermion loops…

High Energy Physics - Phenomenology · Physics 2021-11-01 Ekta Chaubey

In this thesis, we study the all same helicity loop amplitudes in self-dual Yang-Mills and self-dual gravity. These amplitudes have long been conjectured to be interpreted as an anomaly and are recently linked to the UV divergence of…

High Energy Physics - Theory · Physics 2023-10-24 Pratik Chattopadhyay

In this talk we review the recent computation of the five- and six-gluon two-loop amplitudes in Yang-Mills theory using local integrands which make the infrared pole structure manifest. We make some remarks on the connection with BCJ…

High Energy Physics - Phenomenology · Physics 2016-07-04 Simon Badger , Gustav Mogull , Tiziano Peraro

We present a symbol-level bootstrap construction of the planar, two-loop six-gluon scattering amplitude for the --++++ helicity configuration in QCD, focusing on the maximal weight pieces-the "most complicated terms" in the sense of Lipatov…

High Energy Physics - Theory · Physics 2026-03-24 Sérgio Carrôlo , Dmitry Chicherin , Johannes Henn , Qinglin Yang , Yang Zhang

We conjecture a simple relationship between the one-loop maximally helicity violating gluon amplitudes of ordinary QCD (all helicities identical) and those of N=4 supersymmetric Yang-Mills (all but two helicities identical). Because the…

High Energy Physics - Theory · Physics 2009-07-09 Z. Bern , L. Dixon , D. C. Dunbar , D. A. Kosower

We compute the complete one-loop corrections to the simplest class of QCD gluon amplitudes, those with two color-adjacent opposite-helicity external particles. We present results for an arbitrary number of external legs. The computation…

High Energy Physics - Phenomenology · Physics 2009-11-11 Darren Forde , David A. Kosower

In this article we present a method to generate analytic expressions for the integral coefficients of loop amplitudes using numerical evaluations only. We use high-precision arithmetic to explore the singularity structure of the…

High Energy Physics - Phenomenology · Physics 2023-10-09 Giuseppe De Laurentis , Daniel Maître