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arXiv · 2207.03491

Causal Effective Field Theories

Mariana Carrillo Gonzalez·Claudia de Rham·Victor Pozsgay·Andrew J. Tolley
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Abstract

Physical principles such as unitarity, causality, and locality can constrain the space of consistent effective field theories (EFTs) by imposing two-sided bounds on the allowed values of Wilson coefficients. In this paper, we consider the bounds that arise from the requirement of low-energy causality alone, without appealing to any assumptions about UV physics. We focus on shift-symmetric theories, and consider bounds that arise from the propagation around both a homogeneous and a spherically-symmetric background. We find that low-energy causality, namely the requirement that there are no resolvable time advances within the regime of validity of the EFT, produces two-sided bounds in agreement with compact positivity constraints previously obtained from $2 \rightarrow 2$ scattering amplitude dispersion relations using full crossing symmetry.

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Mariana Carrillo Gonzalez, Claudia de Rham, Victor Pozsgay, Andrew J. Tolley. 2023-03-17. Causal Effective Field Theories. https://doi.org/10.1103/physrevd.106.105018

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