Infrared divergences in the perturbative expansion of gauge theory amplitudes and cross
sections have been a focus of theoretical investigations for almost a century. New insights …

We review on-shell methods for computing multi-parton scattering amplitudes in perturbative
QCD, utilizing their unitarity and factorization properties. We focus on aspects which are …

A bstract We present the complete formula for the cusp anomalous dimension at four loops
in QCD and in maximally supersymmetric Yang-Mills. In the latter theory it is given …

A bstract Perturbative scattering amplitudes in gauge theories have remarkable simplicity
and hidden infinite dimensional symmetries that are completely obscured in the …

A bstract We compute the six-particle maximally-helicity-violating (MHV) and next-to-MHV
(NMHV) amplitudes in planar maximally supersymmetric Yang-Mills theory through seven …

We present an identity satisfied by the kinematic factors of diagrams describing the tree
amplitudes of massless gauge theories. This identity is a kinematic analog of the Jacobi …

We study observables in a conformal field theory which are very closely related to the ones
used to describe hadronic events at colliders. We focus on the correlation functions of the …

We give an explicit recursive formula for the all ℓ-loop integrand for scattering amplitudes
in\(\mathcal {N}= 4\) SYM in the planar limit, manifesting the full Yangian symmetry of the …

We discuss possible phase factors for the S-matrix of planar gauge theory, leading to
modifications at four-loop order as compared to an earlier proposal. While these result in a …

We argue that all scattering amplitudes in the maximally supersymmetric N= 4 super-Yang–
Mills theory possess a new, dual superconformal symmetry which extends the previously …