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arXiv · 2603.03423

Unitarity bounds and sum rules in the SMEFT

Luigi C. Bresciani·Paride Paradisi·Andrea Sainaghi
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Abstract

We present a comprehensive reassessment of perturbative unitarity bounds in the dimension-six Standard Model Effective Field Theory, exploiting a new formalism based on spinor-helicity techniques to derive partial-wave unitarity bounds for generic $N \to M$ scattering amplitudes. We find that, in several cases, these theoretical constraints are already competitive with, or even stronger than, the corresponding experimental bounds for energy scales above a few TeV. This is especially the case for four-fermion operators under realistic flavor assumptions, where unitarity bounds can be further strengthened by exploiting sum rules.

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Luigi C. Bresciani, Paride Paradisi, Andrea Sainaghi. 2026-03-03. Unitarity bounds and sum rules in the SMEFT. https://arxiv.org/abs/2603.03423

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