Johannes M. Henn

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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 confor-mal symmetry. To reveal this property we formulate the scattering amplitudes as functions in the appropriate dual superspace. Rewritten in this form, all tree-level MHV and(More)
We give an explicit formula for all tree amplitudes in N = 4 SYM, derived by solving the recently presented supersymmetric tree-level recursion relations. The result is given in a compact, manifestly supersymmetric form and we show how to extract from it all possible component amplitudes for an arbitrary number of external particles and any arrangement of(More)
Tree-level scattering amplitudes in N = 4 super Yang-Mills theory have recently been shown to transform covariantly with respect to a ‘dual’ superconformal symmetry algebra, thus extending the standard superconformal symmetry algebra psu(2, 2|4) of the theory. In this paper we derive the action of the dual superconformal generators in on-shell superspace(More)
Planar gluon amplitudes in N = 4 SYM are remarkably similar to expectation values of Wilson loops made of light-like segments. We argue that the latter can be determined by making use of the conformal symmetry of the gauge theory, broken by cusp anomalies. We derive the corresponding anomalous conformal Ward identities valid to all loops and show that they(More)
There is growing evidence that on-shell gluon scattering amplitudes in planar N = 4 SYM theory are equivalent to Wilson loops evaluated over contours consisting of straight, light-like segments defined by the momenta of the external gluons. This equivalence was first suggested at strong coupling using the AdS/CFT correspondence and has since been verified(More)
We develop a manifestly supersymmetric version of the generalized unitarity cut method for calculating scattering amplitudes in N = 4 SYM theory. We illustrate the power of this method by computing the one-loop n-point NMHV super-amplitudes. The result confirms two conjectures which we made in arXiv:0807.1095 [hep-th]. Firstly, we derive the compact,(More)
We compare the two-loop corrections to the finite part of the light-like hexagon Wilson loop with the recent numerical results for the finite part of the MHV six-gluon amplitude in N = 4 SYM theory [hep-th]) and demonstrate that they coincide within the error bars and, at the same time, they differ from the BDS ansatz by a non-trivial function of (dual)(More)
Scattering amplitudes at loop level can be expressed in terms of Feynman integrals. The latter satisfy partial differential equations in the kinematical variables. We argue that a good choice of basis for (multi)loop integrals can lead to significant simplifications of the differential equations, and propose criteria for finding an optimal basis. This(More)
We provide a simple analytic formula for the two-loop six-point ratio function of planar N = 4 super Yang-Mills theory. This result extends the analytic knowledge of multi-loop six-point amplitudes beyond those with maximal helicity violation. We make a natural ansatz for the symbols of the relevant functions appearing in the two-loop amplitude, and impose(More)