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We propose a method for computing numerically integrals defined via $i \epsilon$ deformations acting on single-pole singularities. We achieve this without an explicit analytic contour deformation. Our solution is then used to produce…

High Energy Physics - Phenomenology · Physics 2022-01-21 Roberto Pittau , Bryan Webber

We study a two-loop contribution to the dark-matter trispectrum and evaluate it numerically using an infrared-safe integrand. The calculation is organized as an expansion around a fixed reference cosmology: the linear matter power spectrum…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-09 Andrea Favorito

We study a recently-proposed approach to the numerical evaluation of multi-loop Feynman integrals using available sector decomposition programs. As our main example, we consider the two-loop integrals for the $\alpha \alpha_s$ corrections…

High Energy Physics - Phenomenology · Physics 2017-11-08 Andreas von Manteuffel , Robert M. Schabinger

We discuss the calculation of two-point three-loop functions with an arbitrary number of massive propagators and one large external momentum. The relevant subdiagrams are generated automatically. The resulting massless two-point integrals…

High Energy Physics - Phenomenology · Physics 2011-04-15 K. G. Chetyrkin , R. Harlander , J. H. Kuehn , M. Steinhauser

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

A framework to represent and compute two-loop $N$-point Feynman diagrams as double-integrals is discussed. The integrands are 'generalised one-loop type" multi-point functions multiplied by simple weighting factors. The final integrations…

High Energy Physics - Phenomenology · Physics 2020-04-15 J. Ph. Guillet , E. Pilon , Y. Shimizu , M. S. Zidi

An analytical approach is applied to the calculation of some dimensionally-regulated two-loop vertex diagrams with essential on-shell singularities. Such diagrams are important for the evaluation of QED corrections to the muon decay, QCD…

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

We present a program for the numerical evaluation of multi-dimensional polynomial parameter integrals. Singularities regulated by dimensional regularisation are extracted using iterated sector decomposition. The program evaluates the…

High Energy Physics - Phenomenology · Physics 2011-05-02 Jonathon Carter , Gudrun Heinrich

Spectral decomposition of matrices is a recurring and important task in applied mathematics, physics and engineering. Many application problems require the consideration of matrices of size three with spectral decomposition over the real…

Numerical Analysis · Mathematics 2021-11-04 Michal Habera , Andreas Zilian

Given the recent progress in computing three-point functions in N=4 SYM via integrability, I provide here a novel direct calculation of some structure constants at weak coupling. The main focus is on correlators involving more than one…

High Energy Physics - Theory · Physics 2019-05-01 Marco S. Bianchi

We propose a new geometric method of IR factorization in sector decomposition. The problem is converted into a set of problems in convex geometry. The latter problems are solved using algorithms in combinatorial geometry. This method…

High Energy Physics - Phenomenology · Physics 2014-11-20 Toshiaki Kaneko , Takahiro Ueda

Motivated by the precision results in the electroweak theory studies of two-loopFeynman diagrams are performed. Specifically this paper gives a contribution to the knowledge of massive two-loop self-energy diagrams in arbitrary and…

High Energy Physics - Phenomenology · Physics 2011-09-30 S. Bauberger , F. A. Berends , M. Boehm , M. Buza

A number of exact results for two-loop three-point diagrams with massless internal particles and arbitrary (off-shell) external momenta are presented. Divergent contributions are calculated in the framework of dimensional regularization.

High Energy Physics - Phenomenology · Physics 2009-10-28 N. I. Ussyukina , A. I. Davydychev

We propose a new method for the computation of quantum three-point functions for operators in su(2) sectors of N=4 super Yang-Mills theory. The method is based on the existence of a unitary transformation relating inhomogeneous and…

High Energy Physics - Theory · Physics 2014-04-11 Yunfeng Jiang , Ivan Kostov , Florian Loebbert , Didina Serban

We present a systematic algorithm for the perturbative computation of soft functions that are defined in terms of two light-like Wilson lines. Our method is based on a universal parametrisation of the phase-space integrals, which we use to…

High Energy Physics - Phenomenology · Physics 2019-09-04 Guido Bell , Rudi Rahn , Jim Talbert

We apply an integral transformation to solutions of a partial differential equation for five-point correlation functions in Liouville theory on a sphere with one degenerate field $V_{-\frac{1}{2b}}$. By repeating this transformation, we can…

High Energy Physics - Theory · Physics 2018-08-15 André Neveu

In this paper, we propose a numerical method of computing an integral whose integrand is a slowly decaying oscillatory function. In the proposed method, we consider a complex analytic function in the upper-half complex plane, which is…

Numerical Analysis · Mathematics 2019-09-12 Hidenori Ogata

We study five-point off-shell conformal integrals and the associated half-BPS correlation functions at two loops in the 't Hooft coupling expansion of maximally supersymmetric Yang-Mills theory. We construct a basis of…

High Energy Physics - Theory · Physics 2026-04-14 Chia-Kai Kuo , Qinglin Yang

Loop amplitudes are conveniently expressed in terms of master integrals whose coefficients carry the process dependent information. Similarly before integration, the loop integrands may be expressed as a linear combination of propagator…

High Energy Physics - Theory · Physics 2016-12-28 Harald Ita

We present the detailed computation of full-color three-loop three-point form factors of both the stress-tensor supermultiplet and a length-three BPS operator in N=4 SYM. The integrands are constructed based on the color-kinematics (CK)…

High Energy Physics - Theory · Physics 2022-03-30 Guanda Lin , Gang Yang , Siyuan Zhang