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We present an algorithm which allows to solve analytically linear systems of differential equations which factorize to first order. The solution is given in terms of iterated integrals over an alphabet where its structure is implied by the…

High Energy Physics - Phenomenology · Physics 2018-12-19 J. Ablinger , J. Blümlein , P. Marquard , N. Rana , C. Schneider

We compute the master integrals for massless two-loop vertex graphs with three off-shell legs. These master integrals are relevant for the QCD corrections to H to V*V* (where V = W, Z) and for two-loop studies of the triple gluon (and…

High Energy Physics - Phenomenology · Physics 2008-11-26 T. G. Birthwright , E. W. N. Glover , P. Marquard

For the two-loop next-to-leading-order electroweak (NLO EW) corrections to $gg \rightarrow ZH$, the light-fermion contributions can be classified into eight distinct topologies. Using the canonical differential-equations method, we perform…

High Energy Physics - Phenomenology · Physics 2026-05-01 Shu-Xiang Li , Ren-You Zhang , Xiao-Feng Wang , Pan-Feng Li , Xiang-Jie Wei , Yi Wang , Yi Jiang , Qing-hai Wang

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 present the analytic calculation of the Master Integrals necessary to compute the planar massive QCD corrections to Di-photon (and Di-jet) production at hadron colliders. The masters are evaluated by means of the differential equations…

High Energy Physics - Phenomenology · Physics 2018-02-14 Matteo Becchetti , Roberto Bonciani

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

An algorithm for the systematic analytical approximation of multi-scale Feynman integrals is presented. The algorithm produces algebraic expressions as functions of the kinematical parameters and mass scales appearing in the Feynman…

High Energy Physics - Phenomenology · Physics 2018-09-26 Sophia Borowka , Thomas Gehrmann , Daniel Hulme

The computation of Feynman integrals often involves square roots. One way to obtain a solution in terms of multiple polylogarithms is to rationalize these square roots by a suitable variable change. We present a program that can be used to…

Mathematical Software · Computer Science 2020-06-24 Marco Besier , Pascal Wasser , Stefan Weinzierl

Feynman integral computations in theoretical high energy particle physics frequently involve square roots in the kinematic variables. Physicists often want to solve Feynman integrals in terms of multiple polylogarithms. One way to obtain a…

Algebraic Geometry · Mathematics 2021-01-01 Marco Besier , Dino Festi

We present a new algorithm for solving an eigenvalue problem for a real symmetric matrix which is a rank-one modification of a diagonal matrix. The algorithm computes each eigenvalue and all components of the corresponding eigenvector with…

Numerical Analysis · Mathematics 2015-09-22 Nevena Jakovcevic Stor , Ivan Slapnicar , Jesse L. Barlow

We calculate convergent 3-loop Feynman diagrams containing a single massive loop equipped with twist $\tau =2$ local operator insertions corresponding to spin $N$. They contribute to the massive operator matrix elements in QCD describing…

High Energy Physics - Phenomenology · Physics 2015-06-19 Jakob Ablinger , Johannes Blümlein , Clemens Raab , Carsten Schneider , Fabian Wißbrock

We provide high-energy approximations for all one-loop scalar 3- and 4-point functions and the corresponding tensor integrals that appear in scattering processes with four external on-shell particles. Our expressions are valid if all…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. Roth , A. Denner

We present results for the corrections of order alpha^2 (Z alpha)^5 to the Lamb shift. We compute all the contributing Feynman diagrams in dimensional regularization and a general covariant gauge using a mixture of analytical and numerical…

High Energy Physics - Phenomenology · Physics 2014-11-20 Matthew Dowling , Jorge Mondejar , Jan H. Piclum , Andrzej Czarnecki

We consider the O(alpha alpha_s) corrections to single on-shell gauge boson production at hadron colliders. We concentrate on the contribution of all the subprocesses where the gauge boson is accompanied by the emission of two additional…

High Energy Physics - Phenomenology · Physics 2017-04-26 Roberto Bonciani , Federico Buccioni , Roberto Mondini , Alessandro Vicini

We present a Mathematica package which finds a basis of master integrals for the Feynman integral reduction. In this basis the dependence on the dimensional regularization in the denominators factorizes in kinematic independent polynomials.

High Energy Physics - Phenomenology · Physics 2020-04-03 Johann Usovitsch

We evaluate analytically the master integrals for one of two types of planar families contributing to massive two-loop Bhabha scattering in QED. As in our previous paper, we apply a recently suggested new strategy to solve differential…

High Energy Physics - Theory · Physics 2015-06-16 Johannes M. Henn , Vladimir A. Smirnov

In the very near future the first data from LHC will be available. The searches for the Higgs boson and for new physics will require precise predictions both for the signal and the background processes. Tree level calculations typically…

High Energy Physics - Phenomenology · Physics 2009-03-06 Thomas Reiter

We study a set of two-loop non-planar master integrals needed for the NNLO QCD corrections to diphoton and dijet production at hadron colliders. The top-sector topology contains an internal massive fermion loop and is known to contain…

High Energy Physics - Theory · Physics 2024-02-13 Taushif Ahmed , Ekta Chaubey , Mandeep Kaur , Sara Maggio

In this paper, we analytically compute all master integrals for one of the two non-planar integral families for five-particle massless scattering at two loops. We first derive an integral basis of 73 integrals with constant leading…

High Energy Physics - Phenomenology · Physics 2019-03-18 D. Chicherin , T. Gehrmann , J. M. Henn , N. A. Lo Presti , V. Mitev , P. Wasser

Differential equations are a powerful tool for evaluating Feynman integrals. Their solution is straightforward if a transformation to a canonical form is found. In this paper, we present an algorithm for finding such a transformation. This…

High Energy Physics - Phenomenology · Physics 2020-06-24 Christoph Dlapa , Johannes Henn , Kai Yan