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In this talk, we discuss how ideas from geometry help to improve Feynman integral reduction and the construction of $\varepsilon$-factorised differential equations. In particular, we outline a systematic procedure to obtain an…

We consider the problem of obtaining higher order in regularization parameter $\epsilon$ analytical results for master integrals with elliptics. The two commonly employed methods are provided by the use of differential equations and direct…

High Energy Physics - Phenomenology · Physics 2022-09-07 M. A. Bezuglov , A. I. Onishchenko

A systematic study of the scalar one-loop two-, three-, and four-point Feynman integrals is performed. We consider all cases of mass assignment and external invariants and derive closed expressions in arbitrary space-time dimension in terms…

High Energy Physics - Phenomenology · Physics 2016-04-14 Johannes Bluemlein , Khiem Hong Phan , Tord Riemann

In this paper we develop and demonstrate a method to obtain epsilon factorized differential equations for elliptic Feynman integrals. This method works by choosing an integral basis with the property that the period matrix obtained by…

High Energy Physics - Theory · Physics 2022-03-30 Hjalte Frellesvig

We describe a systematic approach to cast the differential equation for the $l$-loop equal mass banana integral into an $\varepsilon$-factorised form. With the known boundary value at a specific point we obtain systematically the term of…

High Energy Physics - Theory · Physics 2023-05-10 Sebastian Pögel , Xing Wang , Stefan Weinzierl

We explore inequality constraints as a new tool for numerically evaluating Feynman integrals. A convergent Feynman integral is non-negative if the integrand is non-negative in either loop momentum space or Feynman parameter space. Applying…

High Energy Physics - Phenomenology · Physics 2023-10-05 Mao Zeng

We evaluate the three-loop five-point pentagon-box-box massless integral family in the dimensional regularization scheme, via canonical differential equation. We use tools from computational algebraic geometry to enable the necessary…

High Energy Physics - Phenomenology · Physics 2025-01-15 Yuanche Liu , Antonela Matijašić , Julian Miczajka , Yingxuan Xu , Yongqun Xu , Yang Zhang

The two-loop QCD corrections to vector boson pair production at hadron colliders involve a new class of Feynman integrals: two-loop four-point functions with two off-shell external legs. We describe their reduction to a small set of master…

High Energy Physics - Phenomenology · Physics 2013-08-26 Thomas Gehrmann , Lorenzo Tancredi , Erich Weihs

The method of differential equations has been proven to be a powerful tool for the computation of multi-loop Feynman integrals appearing in quantum field theory. It has been observed that in many instances a canonical basis can be chosen,…

High Energy Physics - Phenomenology · Physics 2017-05-23 Christoph Meyer

We discuss for the first time canonical differential equations for hyperelliptic Feynman integrals. We study hyperelliptic Lauricella functions that include in particular the maximal cut of the two-loop non-planar double box, which is known…

High Energy Physics - Theory · Physics 2025-10-17 Claude Duhr , Franziska Porkert , Sven F. Stawinski

We apply a recently suggested new strategy to solve differential equations for Feynman integrals. We develop this method further by analyzing asymptotic expansions of the integrals. We argue that this allows the systematic application of…

High Energy Physics - Theory · Physics 2015-06-18 Johannes M. Henn , Alexander V. Smirnov , Vladimir A. Smirnov

In this paper we exploit factorisation properties of Picard-Fuchs operators to decouple differential equations for multi-scale Feynman integrals. The algorithm reduces the differential equations to blocks of the size of the order of the…

High Energy Physics - Phenomenology · Physics 2017-04-12 Luise Adams , Ekta Chaubey , Stefan Weinzierl

Some problems related to the structure of higher terms of the epsilon-expansion of Feynman diagrams are discussed.

High Energy Physics - Theory · Physics 2007-05-23 A. I. Davydychev , M. Yu. Kalmykov

We consider the question of reducibility of the differential system to normalized Fuchsian form on the Riemann sphere. The differential equations for the multiloop integrals in $\epsilon$-form constitute a particular example of the…

High Energy Physics - Theory · Physics 2017-07-26 Roman N. Lee , Andrei A. Pomeransky

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 provide a comprehensive summary of concepts from Calabi-Yau motives relevant to the computation of multi-loop Feynman integrals. From this we derive several consequences for multi-loop integrals in general, and we illustrate them on the…

High Energy Physics - Theory · Physics 2022-10-19 Kilian Bönisch , Claude Duhr , Fabian Fischbach , Albrecht Klemm , Christoph Nega

In this paper we study the calculation of multiloop Feynman integrals that cannot be expressed in terms of multiple polylogarithms. We show in detail how certain types of two- and three-point functions at two loops, which appear in the…

High Energy Physics - Phenomenology · Physics 2019-06-26 Johannes Broedel , Claude Duhr , Falko Dulat , Brenda Penante , Lorenzo Tancredi

Problems occurring in physically important non-trivial examples of loop calculations are discussed. A procedure of deriving expansions of two-loop self-energy diagrams with different masses is constructed. The cases of small and large…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. I. Davydychev

A connection between one-loop $N$-point Feynman diagrams and certain geometrical quantities in non-Euclidean geometry is discussed. A geometrical way to calculate the corresponding Feynman integrals is considered. (This paper contains a…

High Energy Physics - Theory · Physics 2011-03-17 A. I. Davydychev , R. Delbourgo

In this talk we show that dual conformal symmetry has unexpected applications to Feynman integrals in dimensional regularization. Outside $4$ dimensions, the symmetry is anomalous, but still preserves the unitarity cut surfaces. This…

High Energy Physics - Theory · Physics 2018-07-24 Zvi Bern , Michael Enciso , Harald Ita , Mao Zeng