Journal of High Energy Physics (Mar 2019)
Cluster adjacency and the four-loop NMHV heptagon
Abstract
Abstract We exploit the recently described property of cluster adjacency for scattering amplitudes in planar N = 4 $$ \mathcal{N}=4 $$ super Yang-Mills theory to construct the symbol of the four-loop NMHV heptagon amplitude. We use a manifestly cluster adjacent ansatz and describe how the parameters of this ansatz are determined using simple physical consistency requirements. We then specialise our answer for the amplitude to the multi-Regge limit, finding agreement with previously available results up to the next-to-leading logarithm, and obtaining new predictions up to (next-to)3-leading-logarithmic accuracy.
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