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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 propose new formulae for the two-loop n-point D-dimensional integrands of scattering amplitudes in Yang-Mills theory and gravity. The loop integrands are written as a double-forward limit of tree-level trivalent diagrams, and are…

High Energy Physics - Theory · Physics 2020-01-29 Yvonne Geyer , Ricardo Monteiro , Ricardo Stark-Muchão

Recent studies of scattering amplitudes in planar N=4 SYM theory revealed the existence of a hidden dual superconformal symmetry. Together with the conventional superconformal symmetry it gives rise to powerful restrictions on the planar…

High Energy Physics - Theory · Physics 2014-11-20 G. P. Korchemsky , E. Sokatchev

Integrands for colour ordered scattering amplitudes in planar N=4 SYM are dual to those of correlation functions of the energy-momentum multiplet of the theory. The construction can relate amplitudes with different numbers of legs. By graph…

High Energy Physics - Theory · Physics 2013-12-05 Raquel G. Ambrosio , Burkhard Eden , Timothy Goddard , Paul Heslop , Charles Taylor

The massless QCD Lagrangian is conformally invariant and, as a consequence, so are the tree-level scattering amplitudes. However, the implications of this powerful symmetry at loop level are only beginning to be explored systematically.…

High Energy Physics - Theory · Physics 2020-03-18 Johannes Henn , Bláithín Power , Simone Zoia

Infrared divergences in scattering amplitudes arise when a loop momentum $\ell$ becomes collinear with a massless external momentum $p$. In gauge theories, it is known that the L-loop logarithm of a planar amplitude has much softer infrared…

High Energy Physics - Theory · Physics 2015-06-03 Jacob L. Bourjaily , Alexander DiRe , Amin Shaikh , Marcus Spradlin , Anastasia Volovich

Tree-level scattering amplitudes in planar N=4 super Yang-Mills are known to be Yangian-invariant. It has been shown that integrability allows to obtain a general, explicit method to find such invariants. The uplifting of this result to the…

High Energy Physics - Theory · Physics 2017-08-02 Livia Ferro , Tomasz Lukowski , Andrea Orta , Matteo Parisi

The calculation of scattering amplitudes in Yang-Mills theory at loop level is important for the analysis of background processes at particle colliders as well as our understanding of perturbation theory at the quantum level. We present…

High Energy Physics - Theory · Physics 2013-05-30 Rutger H. Boels , Reinke Sven Isermann

We propose a new diagrammatic formulation of the all-loop scattering amplitudes/Wilson loops in planar N=4 SYM, dubbed the "momentum-twistor diagrams". These are on-shell-diagrams obtained by gluing trivalent black and white vertices…

High Energy Physics - Theory · Physics 2015-06-22 Yuntao Bai , Song He

Scattering amplitudes with spinning particles are shown to decompose into multiple copies of simple building blocks to all loop orders, which can be used to efficiently reduce these amplitudes to sums over scalar integrals. Absence of…

High Energy Physics - Phenomenology · Physics 2018-05-28 Rutger H. Boels , Qingjun Jin , Hui Luo

This thesis aims at providing better understanding of the perturbative expansion of gauge theories with and without supersymmetry. At tree level, the BCFW recursion relations are analyzed with respect to their validity for general off-shell…

High Energy Physics - Theory · Physics 2014-09-30 Alexander Ochirov

We derive analytic results for the symbol of certain two-loop Feynman integrals relevant for seven- and eight-point two-loop scattering amplitudes in planar $\mathcal{N}=4$ super-Yang--Mills theory. We use a bootstrap inspired strategy,…

High Energy Physics - Theory · Physics 2018-11-14 Johannes Henn , Enrico Herrmann , Julio Parra-Martinez

In this letter, we generalize the recursion methods based on cut equations arXiv:2412.21027, originally developed for scalar theories, to gluons in pure Yang-Mills theory. In gauge theories, planar loop integrands are subtle to defined and…

High Energy Physics - Theory · Physics 2025-03-21 Qu Cao , Fan Zhu

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 investigate the Yangian symmetry of scattering amplitudes in N=4 super Yang-Mills theory and show that its formulations in twistor and momentum twistor space can be interchanged. In particular we show that the full symmetry can be…

High Energy Physics - Theory · Physics 2010-09-09 J. M. Drummond , L. Ferro

We present an explicit analytic calculation of the differential of the planar n-particle, two-loop MHV scattering amplitude in N=4 super Yang-Mills theory. The result is expressed only in terms of the polylogarithm functions Li_k(-x), for…

High Energy Physics - Theory · Physics 2015-06-16 John Golden , Marcus Spradlin

This thesis is focused on the development of new mathematical methods for computing multi-loop scattering amplitudes in gauge theories. In this work we combine, for the first time, the unitarity-based construction for integrands, and the…

High Energy Physics - Phenomenology · Physics 2014-10-21 Ulrich Schubert

We present evidence that loop amplitudes in maximally supersymmetric $\mathcal{N}=4$ Yang-Mills (SYM) beyond the planar limit share some of the remarkable structures of the planar theory. In particular, we show that through two loops, the…

High Energy Physics - Theory · Physics 2015-01-07 Nima Arkani-Hamed , Jacob L. Bourjaily , Freddy Cachazo , Jaroslav Trnka

The scattering equations on the Riemann sphere give rise to remarkable formulae for tree-level gauge theory and gravity amplitudes. Adamo, Casali and Skinner conjectured a one-loop formula for supergravity amplitudes based on scattering…

High Energy Physics - Theory · Physics 2015-09-23 Yvonne Geyer , Lionel Mason , Ricardo Monteiro , Piotr Tourkine

We argue that the scattering amplitudes in the maximally supersymmetric N=4 super-Yang-Mills theory possess a new symmetry which extends the previously discovered dual conformal symmetry. To reveal this property we formulate the scattering…

High Energy Physics - Theory · Physics 2009-12-22 J. M. Drummond , J. Henn , G. P. Korchemsky , E. Sokatchev