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A recently derived approach to the tensor reduction of 5-point one-loop Feynman integrals expresses the tensor coefficients by scalar 1-point to 4-point Feynman integrals completely algebraically. In this letter we derive extremely compact…

High Energy Physics - Phenomenology · Physics 2011-07-20 J. Fleischer , T. Riemann

A new approach is presented to evaluate multi-loop integrals, which appear in the calculation of cross-sections in high-energy physics. It relies on a fully numerical method and is applicable to a wide class of integrals with various mass…

High Energy Physics - Phenomenology · Physics 2015-06-03 F. Yuasa , E. de Doncker , N. Hamaguchi , T. Ishikawa , K. Kato , Y. Kurihara , J. Fujimoto , Y. Shimizu

We apply the analytic conformal bootstrap method to study weakly coupled conformal gauge theories in four dimensions. We employ twist conformal blocks to find the most general form of the one-loop four-point correlation function of…

High Energy Physics - Theory · Physics 2018-04-04 Johan Henriksson , Tomasz Lukowski

Different mathematical methods have been applied to obtain the analytic result for the massless triangle Feynman diagram yielding a sum of four linearly independent hypergeometric functions $F_4$. In this paper I work out the diagram and…

High Energy Physics - Theory · Physics 2008-08-12 Alfredo Takashi Suzuki

In this work, we study the computation of reduction coefficients for multi loop Feynman integrals using generating functions constructed within the Baikov representation. Compared with traditional Feynman rules, the Baikov formalism offers…

High Energy Physics - Theory · Physics 2025-12-22 Chang Hu , Wen-Di Li , Xiang Li

We present a reconstruction method that stably recovers the real valued, symmetric tensors compactly supported in the Euclidean plane, from knowledge of their attenuated momenta ray transform. The problem is recast as an inverse boundary…

Analysis of PDEs · Mathematics 2024-05-09 Hiroshi Fujiwara , David Omogbhe , Kamran Sadiq , Alexandru Tamasan

We explore maximal unitarity for nonplanar two-loop integrals with up to four massive external legs. In this framework, the amplitude is reduced to a basis of master integrals whose coefficients are extracted from maximal cuts. The…

High Energy Physics - Theory · Physics 2016-12-30 Mads Sogaard , Yang Zhang

The decomposition of the four-point ABJM amplituhedron into negative geometries produces compact integrands of logarithmic of amplitudes such that the infrared divergence only comes from the last loop integration, from which we can compute…

High Energy Physics - Theory · Physics 2025-01-20 Zhenjie Li

We propose a dimension reduction technique for Bayesian inverse problems with nonlinear forward operators, non-Gaussian priors, and non-Gaussian observation noise. The likelihood function is approximated by a ridge function, i.e., a map…

Probability · Mathematics 2022-01-31 Olivier Zahm , Tiangang Cui , Kody Law , Alessio Spantini , Youssef Marzouk

A modular application of the integration by fractional expansion (IBFE) method for evaluating Feynman diagrams is extended to diagrams that contain loop triangle subdiagrams in their geometry. The technique is based in the replacement of…

High Energy Physics - Theory · Physics 2009-07-09 Ivan Gonzalez , Ivan Schmidt

The scalar two-loop self-energy master diagram is studied in the case of arbitrary masses. Analytical results in terms of Lauricella- and Appell-functions are presented for the imaginary part. By using the dispersion relation a…

High Energy Physics - Phenomenology · Physics 2009-10-28 S. Bauberger , M. Boehm

We perform a complete analytical reduction of general one-loop Feynman integrals with five and six external legs for tensors up to rank R=3 and 4, respectively. An elegant formalism with extensive use of signed minors is developed for the…

High Energy Physics - Phenomenology · Physics 2009-09-02 Th. Diakonidis , J. Fleischer , J. Gluza , K. Kajda , T. Riemann , J. B. Tausk

We employ the Forcer algorithm to renormalize a variety of six dimensional field theories to four loops. In order to achieve this we construct the Forcer master integrals in six dimensions from their four dimensional counterparts by using…

High Energy Physics - Theory · Physics 2024-07-18 J. A. Gracey

We study a novel geometric expansion for scattering amplitudes in the planar sector of N=4 super Yang-Mills theory, in the context of the Amplituhedron which reproduces the all-loop integrand as a canonical differential form on the positive…

High Energy Physics - Theory · Physics 2024-01-01 Taro V. Brown , Umut Oktem , Shruti Paranjape , Jaroslav Trnka

The worldline formalism offers an alternative framework to the standard diagrammatic approach in quantum field theory, grounded in first-quantized relativistic path integrals. Over recent decades, this formalism has attracted growing…

High Energy Physics - Theory · Physics 2025-05-08 Victor Miguel Banda Guzmán

This paper is concerned with the ubiquitous inverse problem of recovering an unknown function u from finitely many measurements possibly affected by noise. In recent years, inversion methods based on linear approximation spaces were…

Numerical Analysis · Mathematics 2022-10-06 Albert Cohen , Matthieu Dolbeault , Olga Mula , Agustin Somacal

We discuss recent progress in multi-loop integrand reduction methods. Motivated by the possibility of an automated construction of multi-loop amplitudes via generalized unitarity cuts we describe a procedure to obtain a general…

High Energy Physics - Phenomenology · Physics 2015-06-17 Simon Badger , Hjalte Frellesvig , Yang Zhang

We introduce a novel construction of a contour deformation within the framework of Loop-Tree Duality for the numerical computation of loop integrals featuring threshold singularities in momentum space. The functional form of our contour…

High Energy Physics - Phenomenology · Physics 2020-11-24 Zeno Capatti , Valentin Hirschi , Dario Kermanschah , Andrea Pelloni , Ben Ruijl

In our previous paper [Nucl.Phys. B 870 (2013) 243], we showed that multi-fold Mellin-Barnes (MB) transforms of Usyukina-Davydychev (UD) functions may be reduced to two-fold MB transforms. The MB transforms were written there as polynomials…

High Energy Physics - Theory · Physics 2015-06-15 Bernd Kniehl , Igor Kondrashuk , Eduardo A. Notte-Cuello , Ivan Parra Ferrada , Marko Rojas-Medar

A fully numerical method to calculate loop integrals, a numerical contour-integration method, is proposed. Loop integrals can be interpreted as a contour integral in a complex plane for an integrand with multi-poles in the plane. Stable and…

High Energy Physics - Phenomenology · Physics 2009-11-11 Y. Kurihara , T. Kaneko