Harmonic R-matrices for Scattering Amplitudes and Spectral Regularization
Livia Ferro
Ferro
Livia
Tomasz Lukowski
Lukowski
Tomasz
Carlo Meneghelli
Meneghelli
Carlo
Jan Plefka
Plefka
Jan
Matthias Staudacher
Staudacher
Matthias
Livia Ferro
,
Tomasz Lukowski
,
Carlo Meneghelli
,
Jan Plefka
,
Matthias Staudacher

**PACS:** 11.55.-m

**Abstract**

Planar N=4 super Yang-Mills appears to be integrable. While this allows to find this theory's exact spectrum, integrability has hitherto been of no direct use for scattering amplitudes. To remedy this, we deform all scattering amplitudes by a spectral parameter. The deformed tree-level four-point function turns out to be essentially the one-loop R-matrix of the integrable N=4 spin chain satisfying the Yang-Baxter equation. Deformed on-shell three-point functions yield novel three-leg R-matrices satisfying bootstrap equations. Finally, we supply initial evidence that the spectral parameter might find its use as a novel symmetry-respecting regulator replacing dimensional regularization. Its physical meaning is a local deformation of particle helicity, a fact which might be useful for a much larger class of non-integrable four-dimensional field theories.

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