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arXiv · 2610.36052

The Harmonic Structure of Multiparticle Scattering: Amplitude Projection and Non-Renormalization

Nathaniel Craig·Brian Henning·Michael Stadlbauer
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Abstract

We develop a projection formalism for four-dimensional massless scattering amplitudes based on the construction of harmonics on multi-particle phase space. This provides a generalization of the partial-wave decomposition valid for any number of particles. Applying this formalism to calculations of on-shell cuts, we show that any cut calculation can be rewritten as a sum of products of projected coefficients and derive a condition for this sum to vanish. Using the on-shell renormalization group equation in combination with our projection formalism, we derive new non-renormalization theorems for effective field theories valid at general loop orders.

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Nathaniel Craig, Brian Henning, Michael Stadlbauer. 2026-10-26. The Harmonic Structure of Multiparticle Scattering: Amplitude Projection and Non-Renormalization. https://arxiv.org/abs/2610.36052

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