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In a recent paper, here referred to as part I, we considered the celestial four-gluon amplitude with one gluon represented by the shadow transform of the corresponding primary field operator. This correlator is ill-defined because it…

High Energy Physics - Theory · Physics 2021-12-08 Wei Fan , Angelos Fotopoulos , Stephan Stieberger , Tomasz R. Taylor , Bin Zhu

We explain how one-loop amplitudes with massive fermions can be computed using only on-shell information. We first use the spinor-helicity formalism in six dimensions to perform generalised unitarity cuts in $d$ dimensions. We then show…

High Energy Physics - Phenomenology · Physics 2017-08-02 Simon Badger , Christian Brønnum-Hansen , Francesco Buciuni , Donal O'Connell

This paper presents an evaluation of the wave function coefficients for conformally coupled scalars at both one and two-loop levels at leading order in the coupling constant, in momentum space. We take cues from time-dependent interactions…

High Energy Physics - Theory · Physics 2025-03-06 Chandramouli Chowdhury , Kajal Singh

In these lectures we discuss some of the mathematical structures that appear when computing multi-loop Feynman integrals. We focus on a specific class of special functions, the so-called multiple polylogarithms, and discuss introduce their…

High Energy Physics - Phenomenology · Physics 2014-12-01 Claude Duhr

This article is the second of a series of three presenting an alternative method to compute the one-loop scalar integrals. It extends the results of the first article to general complex masses. Let us remind the main features enjoyed by…

High Energy Physics - Theory · Physics 2020-02-26 J. Ph. Guillet , E. Pilon , Y. Shimizu , M. S. Zidi

In recent work we have developed a new unfolding method for computing one-loop modular integrals in string theory involving the Narain partition function and, possibly, a weak almost holomorphic elliptic genus. Unlike the traditional…

High Energy Physics - Theory · Physics 2015-06-15 Carlo Angelantonj , Ioannis Florakis , Boris Pioline

We use the method of differential equations to analytically evaluate all planar three-loop Feynman integrals relevant for form factor calculations involving massive particles. Our results for ninety master integrals at general $q^2$ are…

High Energy Physics - Phenomenology · Physics 2017-02-01 Johannes M. Henn , Alexander V. Smirnov , Vladimir A. Smirnov

We compute the two-loop master integrals for leading-color QCD scattering amplitudes including a closed light-quark loop in $t\bar{t}H$ production at hadron colliders. Exploiting numerical evaluations in modular arithmetic, we construct a…

High Energy Physics - Phenomenology · Physics 2024-07-18 F. Febres Cordero , G. Figueiredo , M. Kraus , B. Page , L. Reina

In this work, we systematically analyse Feynman integrals in the `t Hooft-Veltman scheme. We write an explicit reduction resulting from partial fractioning the high-multiplicity integrands to a finite basis of topologies at any given loop…

High Energy Physics - Phenomenology · Physics 2024-11-28 Piotr Bargiela , Tong-Zhi Yang

Affine transformations in Euclidean space generates a correspondence between integrable systems on cotangent bundles to the sphere, ellipsoid and hyperboloid embedded in $R^n$. Using this correspondence and the suitable coupling constant…

Exactly Solvable and Integrable Systems · Physics 2022-11-17 A. V. Tsiganov

We report on the calculation of multi-loop Feynman integrals for single-scale problems by means of difference equations in Mellin space. The solution to these difference equations in terms of harmonic sums can be constructed algorithmically…

Mathematical Physics · Physics 2008-12-18 S. Moch , C. Schneider

We use the recently developed generalized double-copy procedure to construct an integrand for the five-loop four-point amplitude of N=8 supergravity. This construction starts from a naive double copy of the previously computed corresponding…

High Energy Physics - Theory · Physics 2017-12-27 Zvi Bern , John Joseph M. Carrasco , Wei-Ming Chen , Henrik Johansson , Radu Roiban , Mao Zeng

We reduce the computation of three point function of three spinning operators with arbitrary polarizations to a statistical mechanics problem via the hexagon formalism. The central building block of these correlation functions is the…

High Energy Physics - Theory · Physics 2022-10-19 Carlos Bercini , Vasco Goncalves , Alexandre Homrich , Pedro Vieira

Modern particle physics is increasingly becoming a precision science that relies on advanced theoretical predictions for the analysis and interpretation of experimental results. The planned physics program at the LHC and future colliders…

High Energy Physics - Phenomenology · Physics 2023-01-04 Ievgen Dubovyk , Ayres Freitas , Janusz Gluza , Krzysztof Grzanka , Martijn Hidding , Johann Usovitsch

We propose a definition of Mellin amplitudes for conformal correlators involving arbitrary spinning operators in tensor representations of the Lorentz group. These representations cover all bosonic local operators. Our strategy is to…

High Energy Physics - Theory · Physics 2025-10-10 Zhongjie Huang , Yichao Tang

In this paper, we outline a method to compute supersymmetric one-loop integrands in ten-dimensional SYM theory. It relies on the constructive interplay between their cubic-graph organization and BRST invariance of the underlying pure spinor…

High Energy Physics - Theory · Physics 2016-01-20 Carlos R. Mafra , Oliver Schlotterer

We evaluate the massless one-loop hexagon integral in six dimensions. The result is given in terms of standard polylogarithms of uniform transcendental weight three, its functional form resembling the one of the remainder function of the…

High Energy Physics - Theory · Physics 2015-05-27 Vittorio Del Duca , Claude Duhr , Vladimir A. Smirnov

Scattering amplitudes with spinning particles are shown to decompose into multiple copies of simple building blocks to all loop orders, which can be used to efficiently reduce these amplitudes to sums over scalar integrals. Absence of…

High Energy Physics - Phenomenology · Physics 2018-05-28 Rutger H. Boels , Qingjun Jin , Hui Luo

In the planar N=4 supersymmetric Yang-Mills theory, the conformal symmetry constrains multi-loop n-edged Wilson loops to be given in terms of the one-loop n-edged Wilson loop, augmented, for n greater than 6, by a function of conformally…

High Energy Physics - Theory · Physics 2014-11-20 Vittorio Del Duca , Claude Duhr , Vladimir A. Smirnov

An analytical-numeric calculation method of extremely complicated integrals is presented. These integrals appear often in magnet soliton theory. The appropriate analytical continuation and a corresponding integration contour allow to reduce…

Computational Physics · Physics 2007-05-23 A. A. Zhmudsky