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Related papers: Cutting massless four-loop propagators

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We present analytical expressions for the 31 five-particle phase-space master integrals in massless QCD as an $\epsilon$-series with coefficients being multiple zeta values of weight up to 12. In addition, we provide a computer code for the…

High Energy Physics - Phenomenology · Physics 2018-08-16 O. Gituliar , V. Magerya , A. Pikelner

We present the analytic computation of the master integrals associated to certain two-loop non-planar topologies, which are needed to complete the evaluation of the last two color coefficients for the top-pair production in the…

High Energy Physics - Phenomenology · Physics 2019-12-13 Matteo Becchetti , Roberto Bonciani , Valerio Casconi , Andrea Ferroglia , Simone Lavacca , Andreas von Manteuffel

Unitarity cuts are widely used in analytic computation of loop amplitudes in gauge theories such as QCD. We expand upon the technique introduced in hep-ph/0503132 to carry out any finite unitarity cut integral. This technique naturally…

High Energy Physics - Phenomenology · Physics 2011-05-05 Ruth Britto , Bo Feng , Pierpaolo Mastrolia

We show how generalised unitarity cuts in D = 4 - 2 epsilon dimensions can be used to calculate efficiently complete one-loop scattering amplitudes in non-supersymmetric Yang-Mills theory. This approach naturally generates the rational…

High Energy Physics - Theory · Physics 2009-11-11 Andreas Brandhuber , Simon McNamara , Bill Spence , Gabriele Travaglini

We show that the evaluation of scattering amplitudes can be formulated as a problem of multivariate polynomial division, with the components of the integration-momenta as indeterminates. We present a recurrence relation which, independently…

High Energy Physics - Phenomenology · Physics 2015-06-05 Pierpaolo Mastrolia , Edoardo Mirabella , Giovanni Ossola , Tiziano Peraro

One-loop amplitudes of gluons in N=4 gauge theory can be written as linear combinations of known scalar box integrals with coefficients that are rational functions. In this paper we show how to use generalized unitarity to basically read…

High Energy Physics - Theory · Physics 2009-11-10 Ruth Britto , Freddy Cachazo , Bo Feng

We derive the full system of canonical differential equations for all planar two-loop massless six-particle master integrals, and determine analytically the boundary conditions. This fully specifies the solutions, which may be written as…

High Energy Physics - Phenomenology · Physics 2025-01-20 Johannes Henn , Antonela Matijašić , Julian Miczajka , Tiziano Peraro , Yingxuan Xu , Yang Zhang

We compute the two-loop master integrals for leading-color QCD scattering amplitudes including a closed light-quark loop in $t\bar{t}H$ production at hadron colliders. Exploiting numerical evaluations in modular arithmetic, we construct a…

High Energy Physics - Phenomenology · Physics 2024-07-18 F. Febres Cordero , G. Figueiredo , M. Kraus , B. Page , L. Reina

We present a new formulation of the loop-tree duality theorem for higher loop diagrams valid both for massless and massive cases. $l$-loop integrals are expressed as weighted sum of trees obtained from cutting $l$ internal propagators of…

High Energy Physics - Phenomenology · Physics 2019-11-22 Robert Runkel , Zoltán Szőr , Juan Pablo Vesga , Stefan Weinzierl

The four-loop, two-point form factor contains the first non-planar correction to the lightlike cusp anomalous dimension. This anomalous dimension is a universal function which appears in many applications. Its planar part in N = 4 SYM is…

High Energy Physics - Theory · Physics 2016-01-19 Rutger Boels , Bernd A. Kniehl , Gang Yang

We show how to compute the coefficients of the double box basis integrals in a massless four-point amplitude in terms of tree amplitudes. We show how to choose suitable multidimensional contours for performing the required cuts, and derive…

High Energy Physics - Theory · Physics 2013-05-30 David A. Kosower , Kasper J. Larsen

We present a set of algebraic functions for evaluating the coefficients of the scalar integral basis of a general one-loop amplitude. The functions are derived from unitarity cuts, but the complete cut-integral procedure has been carried…

High Energy Physics - Phenomenology · Physics 2008-11-26 Ruth Britto , Bo Feng

We evaluate, exactly in d, the master integrals contributing to massless three-loop QCD form factors. The calculation is based on a combination of a method recently suggested by one of the authors (R.L.) with other techniques: sector…

High Energy Physics - Phenomenology · Physics 2015-03-13 R. N. Lee , A. V. Smirnov , V. A. Smirnov

We study the three-loop four-point amplitude in ABJM theory. We determine the dual conformal invariant integrals with highest number of propagators and fix their coefficients by two-particle cuts. Evaluating such a combination of integrals…

High Energy Physics - Theory · Physics 2015-06-19 Marco S. Bianchi , Matias Leoni

We studied the two-loop non-factorizable Feynman diagrams for the $t$-channel single-top production process in quantum chromodynamics. We present a systematic computation of master integrals of the two-loop Feynman diagrams with one…

High Energy Physics - Phenomenology · Physics 2023-07-12 Zihao Wu , Ming-Ming Long

We present a complete reevaluation of the irreducible two-loop vacuum-polarization correction to the photon propagator in quantum electrodynamics, i.e. with an electron-positron pair in the fermion propagators. The integration is carried…

High Energy Physics - Phenomenology · Physics 2024-07-11 S. Laporta , U. D. Jentschura

An exact expression for the master integral I_2 arising in three-loop on-shell HQET propagator diagrams with mass is derived and its analytical expansion in the dimensional regularization parameter epsilon is given.

High Energy Physics - Phenomenology · Physics 2008-11-26 A. G. Grozin , T. Huber , D. Maitre

We compute all planar two-loop six-point Feynman integrals entering scattering observables in massless gauge theories such as QCD. A central result of this paper is the formulation of the differential-equations method under the algebraic…

High Energy Physics - Phenomenology · Physics 2024-12-31 Samuel Abreu , Pier Francesco Monni , Ben Page , Johann Usovitsch

A method for calculating phase-space master integrals for the decay process $1 \to n$ massless partons in QCD using integration-by-parts and differential equations techniques is discussed. The method is based on the appropriate choice of…

High Energy Physics - Phenomenology · Physics 2016-03-23 O. Gituliar

In this letter we continue the calculation of master integrals for massless three-loop form factors by giving analytical results for those integrals which are relevant for the fermionic contributions proportional to N_F^2, N_F*N, and N_F/N.…

High Energy Physics - Phenomenology · Physics 2008-11-26 G. Heinrich , T. Huber , D. Maitre
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