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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

A method for the evaluation of the epsilon expansion of multi-loop massless Feynman integrals is introduced. This method is based on the Gegenbauer polynomial technique and the expansion of the Gamma function in terms of harmonic sums.…

High Energy Physics - Phenomenology · Physics 2007-05-23 Stefan Bekavac

We present an algorithm to evaluate multiloop Feynman integrals with an arbitrary number of internal massive lines, with the masses being in general complex-valued, and its implementation in the \textsc{Mathematica} package…

High Energy Physics - Phenomenology · Physics 2022-10-24 Tommaso Armadillo , Roberto Bonciani , Simone Devoto , Narayan Rana , Alessandro Vicini

The operator approach to analytical evaluation of multi-loop Feynman diagrams is proposed. We show that the known analytical methods of evaluation of massless Feynman integrals, such as the integration by parts method and the method of…

High Energy Physics - Theory · Physics 2008-11-26 A. P. Isaev

We introduce a new method to evaluate algebraic integrals over the simplex numerically. This new approach employs techniques from tropical geometry and exceeds the capabilities of existing numerical methods by an order of magnitude. The…

Mathematical Physics · Physics 2023-10-23 Michael Borinsky

One of the main difficulties in studying Quantum Field Theory, in the perturbative regime, is the calculation of D-dimensional Feynman integrals. In general, one introduces the so-called Feynman parameters and associated with them the…

High Energy Physics - Theory · Physics 2008-11-26 A. T. Suzuki , A. G. M. Schmidt

We describe three algorithms for computer-aided symbolic multi-loop calculations that facilitated some recent novel results. First, we discuss an algorithm to derive the canonical form of an arbitrary Feynman integral in order to facilitate…

High Energy Physics - Phenomenology · Physics 2015-06-03 Alexey Pak

A numerical program is presented which facilitates a computation pertaining to the full set of one-gluon loop diagrams (including ghost loop contributions), with M attached external gluon lines in all possible ways. The feasibility of such…

High Energy Physics - Theory · Physics 2009-11-11 A. S. Kapoyannis , A. I. Karanikas , C. N. Ktorides

We present a new approach for obtaining very precise integration results for infrared vertex and box diagrams, where the integration is carried out directly without performing any analytic integration of Feynman parameters. Using an…

High Energy Physics - Phenomenology · Physics 2008-12-18 F. Yuasa , E. de Doncker , J. Fujimoto , N. Hamaguchi , T. Ishikawa , Y. Shimizu

This article describes three Mathematica packages for the automatic calculation of one-loop Feynman diagrams: the diagrams are generated with FeynArts, algebraically simplified with FormCalc, and finally evaluated numerically using the…

High Energy Physics - Phenomenology · Physics 2009-10-31 T. Hahn

In the calculation of cross sections for infrared-safe observables in high energy collisions at next-to-leading order, one approach is to perform all of the integrations, including the virtual loop integration numerically. One would use a…

High Energy Physics - Phenomenology · Physics 2008-11-26 Zoltan Nagy , Davison E. Soper

We discuss a progress in calculations of Feynman integrals based on the Gegenbauer Polynomial Technique and the Differential Equation Method. We demonstrate the results for a class of two-point two-loop diagrams and the evaluation of most…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. V. Kotikov

We present a set of Feynman integrals appearing in calculations of different QED processes to the one-loop accuracy. We consider scalar, vector, and tensor integrals with two, three, four and five denominators. The cases of equal and…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. B. Arbuzov , A. V. Belitsky , E. A. Kuraev , B. G. Shaikhatdenov

In a previous paper a new approach has been introduced for computing, recursively and numerically, one-loop tensor integrals. Here we describe a few modifications of the original method that allow a more efficient numerical implementation…

High Energy Physics - Phenomenology · Physics 2007-05-23 R. Pittau

We propose a novel method to compute multi-loop master integrals by constructing and numerically solving a system of ordinary differential equations, with almost trivial boundary conditions. Thus it can be systematically applied to problems…

High Energy Physics - Phenomenology · Physics 2018-02-28 Xiao Liu , Yan-Qing Ma , Chen-Yu Wang

Three programs are presented for automatically generating and calculating Feynman diagrams: the diagrams are generated with FeynArts, algebraically simplified with FormCalc, and finally evaluated numerically using the LoopTools package. The…

High Energy Physics - Phenomenology · Physics 2011-04-15 T. Hahn

In this paper we describe a method of calculation of master integrals based on the solution of systems of difference equations in one variable. Various explicit examples are given, as well as the generalization to arbitrary diagrams.

High Energy Physics - Phenomenology · Physics 2007-05-23 S. Laporta

We present a method to evaluate numerically Feynman diagrams directly from their Feynman parameters representation. We first disentangle overlapping singularities using sector decomposition. Threshold singularities are treated with an…

High Energy Physics - Phenomenology · Physics 2010-10-27 Charalampos Anastasiou , Stefan Beerli , Alejandro Daleo

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

For the investigation of higher order Feynman integrals, potentially with tensor structure, it is highly desirable to have numerical methods and automated tools for dedicated, but sufficiently 'simple' numerical approaches. We elaborate two…

High Energy Physics - Phenomenology · Physics 2011-03-03 Janusz Gluza , Krzysztof Kajda , Tord Riemann , Valery Yundin