Non-Forward UV/IR Relations

TL;DR

This paper develops a novel method to derive bounds on effective field theories with massless particles by using dispersion relations away from the forward limit, avoiding singularities and applicable even with gravity.

Contribution

It introduces an approach that relies solely on non-forward dispersion relations, making the bounds more robust against radiative corrections and applicable in gravitational contexts.

Findings

Provides bounds that are valid away from the forward limit.

Avoids Coulomb pole and loop divergence issues.

Applicable to theories including gravity.

Abstract

We study bounds arising from the analyticity and unitarity of scattering amplitudes in the context of effective field theories with massless particles. We provide an approach that only uses dispersion relations away from the forward limit. This is suitable to derive constraints in the presence of gravity, in a way that is robust with respect to radiative corrections. Our method not only allows us to avoid the Coulomb pole, but also the singularities associated with calculable loop effects, which would otherwise diverge.