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Rigorous Bounds on Light-by-Light Scattering

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arxiv 2107.13009 v3 pith:Y2FQDH6R submitted 2021-07-27 hep-th hep-ph

Rigorous Bounds on Light-by-Light Scattering

classification hep-th hep-ph
keywords boundsamplitudesfourrigorousscatteringallowsappearingarise
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved
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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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Cited by 11 Pith papers

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