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We present a symbol-level bootstrap construction of the planar, two-loop six-gluon scattering amplitude for the --++++ helicity configuration in QCD, focusing on the maximal weight pieces-the "most complicated terms" in the sense of Lipatov…

High Energy Physics - Theory · Physics 2026-03-24 Sérgio Carrôlo , Dmitry Chicherin , Johannes Henn , Qinglin Yang , Yang Zhang

Motivated by reformulating Yangian invariants in planar ${\cal N}=4$ SYM directly as $d\log$ forms on momentum-twistor space, we propose a purely algebraic problem of determining the arguments of the $d\log$'s, which we call "letters", for…

High Energy Physics - Theory · Physics 2021-03-17 Song He , Zhenjie Li

The calculation of hard scattering amplitudes up to NLO is automated in numerical tools, such as OpenLoops. The LHC and future experiments, however, demand high-precision predictions at NNLO and beyond for a wide range of particle…

High Energy Physics - Phenomenology · Physics 2024-12-20 Natalie Schär , Max F. Zoller

In these lectures we discuss some of the mathematical structures that appear when computing multi-loop Feynman integrals. We focus on a specific class of special functions, the so-called multiple polylogarithms, and discuss introduce their…

High Energy Physics - Phenomenology · Physics 2014-12-01 Claude Duhr

The scattering equations provide a powerful framework for the study of scattering amplitudes in a variety of theories. Their derivation from ambitwistor string theory led to proposals for formulae at one loop on a torus for 10 dimensional…

High Energy Physics - Theory · Physics 2016-04-20 Yvonne Geyer , Lionel Mason , Ricardo Monteiro , Piotr Tourkine

We give a representation of the parity-even part of the planar two-loop six-gluon MHV amplitude of N=4 super-Yang-Mills theory, in terms of loop-momentum integrals with simple dual conformal properties. We evaluate the integrals numerically…

High Energy Physics - Theory · Physics 2008-11-26 Z. Bern , L. J. Dixon , D. A. Kosower , R. Roiban , M. Spradlin , C. Vergu , A. Volovich

In this sequel calculation of the one-loop Feynman integral pertaining to a massive box diagram contributing to the photon-photon scattering amplitude in quantum electrodynamics, we present the six solutions as yet unknown in the…

High Energy Physics - Theory · Physics 2007-05-23 Alfredo T. Suzuki , Alexandre G. M. Schmidt

Recently, an explicit, recursive formula for the all-loop integrand of planar scattering amplitudes in N=4 SYM has been described, generalizing the BCFW formula for tree amplitudes, and making manifest the Yangian symmetry of the theory.…

High Energy Physics - Theory · Physics 2015-05-20 Nima Arkani-Hamed , Jacob L. Bourjaily , Freddy Cachazo , Jaroslav Trnka

We present new and explicit formulae for the one-loop integrands of scattering amplitudes in non-supersymmetric gauge theory and gravity, valid for any number of particles. The results exhibit the colour-kinematics duality in gauge theory…

High Energy Physics - Theory · Physics 2018-04-04 Yvonne Geyer , Ricardo Monteiro

Elliptic multiple polylogarithms occur in Feynman integrals and in particular in scattering amplitudes. They can be characterized by their symbol, a tensor product in the so-called symbol letters. In contrast to the non-elliptic case, the…

High Energy Physics - Theory · Physics 2023-02-06 Matthias Wilhelm , Chi Zhang

A non-trivial consequence of the super-correlator/super-amplitude duality is that the integrand of the four-point correlation function of stress-tensor multiplets in planar N=4 super Yang-Mills contains a certain combination of n-point…

High Energy Physics - Theory · Physics 2018-08-01 Paul Heslop , Vuong-Viet Tran

We compute the one-loop expectation value of light-like polygonal Wilson loops in N=4 super-Yang-Mills theory in full superspace. When projecting to chiral superspace we recover the known results for tree-level…

High Energy Physics - Theory · Physics 2012-06-18 Niklas Beisert , Song He , Burkhard U. W. Schwab , Cristian Vergu

We revisit the symbol bootstrap program for the seven-particle MHV and NMHV amplitudes in planar $\mathcal{N}=4$ super-Yang-Mills (SYM) based on the alphabet associated with the $E_6$ cluster algebra. After imposing integrability, cluster…

High Energy Physics - Theory · Physics 2025-11-24 Song He , Xuhang Jiang , Xiang Li , Jiahao Liu

Scattering amplitudes in maximally supersymmetric gauge theory receive a dual description in terms of the expectation value of the super Wilson loop stretched on a null polygonal contour. This makes the analysis amenable to nonperturbative…

High Energy Physics - Theory · Physics 2015-12-09 A. V. Belitsky

We take the first step in generalizing the so-called "Schubert analysis", originally proposed in twistor space for four-dimensional kinematics, to the study of symbol letters and more detailed information on canonical differential equations…

High Energy Physics - Theory · Physics 2023-09-29 Song He , Xuhang Jiang , Jiahao Liu , Qinglin Yang

We discuss the computational complexity of the perturbative evaluation of scattering amplitudes, both by the Caravaglios-Moretti algorithm and by direct evaluation of the individual diagrams. For a self-interacting scalar theory, we…

High Energy Physics - Phenomenology · Physics 2009-11-10 Ernst van Eijk , Ronald Kleiss , Achilleas Lazopoulos

We present a method to compute the integrands of one-loop Einstein-Yang-Mills amplitudes for any number of external gauge and gravity multiplets. Our construction relies on the double-copy structure of Einstein-Yang-Mills as…

High Energy Physics - Theory · Physics 2023-03-01 Franziska Porkert , Oliver Schlotterer

We confirm by explicit computation the conjectured all-orders iteration of planar maximally supersymmetric N=4 Yang-Mills theory in the nontrivial case of five-point two-loop amplitudes. We compute the required unitarity cuts of the…

High Energy Physics - Theory · Physics 2008-11-26 Z. Bern , M. Czakon , D. A. Kosower , R. Roiban , V. A. Smirnov

We compute three families of two-loop six-point massless Feynman integrals in dimensional regularization, namely the double-box, the pentagon-triangle, and the hegaxon-bubble family. This constitutes the first analytic computation of…

High Energy Physics - Phenomenology · Physics 2024-04-01 Johannes M. Henn , Antonela Matijašić , Julian Miczajka , Tiziano Peraro , Yingxuan Xu , Yang Zhang

We provide an analytic formula for the (rescaled) one-loop scalar hexagon integral $\tilde\Phi_6$ with all external legs massless, in terms of classical polylogarithms. We show that this integral is closely connected to two integrals…

High Energy Physics - Theory · Physics 2017-09-07 Lance J. Dixon , James M. Drummond , Johannes M. Henn