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arXiv · 2107.13009

Rigorous Bounds on Light-by-Light Scattering

Johan Henriksson·Brian McPeak·Francesco Russo·Alessandro Vichi
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Abstract

We bound EFT coefficients appearing in $2 \to 2$ photon scattering amplitudes in four dimensions. After reviewing unitarity and positivity conditions in this context, we use dispersion relations and crossing symmetry to compute sum rules and null constraints. This allows us to derive new rigorous bounds on operators with four, six, and eight derivatives, including two-sided bounds on their ratios. Comparing with a number of partial UV completions, we find that some of our bounds are saturated by the amplitudes that arise from integrating out a massive scalar or axion, while others suggest the existence of unknown amplitudes.

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Johan Henriksson, Brian McPeak, Francesco Russo, Alessandro Vichi. 2021-07-27. Rigorous Bounds on Light-by-Light Scattering. https://doi.org/10.1007/jhep06(2022)158

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