Regarding the Radion in Randall-Sundrum Models with Brane Curvature

TL;DR

This paper examines how localized brane curvature influences the properties of the radion in Randall-Sundrum models, including its mass, coupling, and kinetic mixing, with implications for dual 4D theories.

Contribution

It provides a detailed analysis of the impact of brane curvature on radion characteristics and explores radion/Higgs mixing and potential ghost-like behavior in stabilized Randall-Sundrum models.

Findings

Radion mass and coupling are sensitive to brane curvature.

Radion/Higgs kinetic mixing can lead to ghost-like radion states.

IR localized terms involving the radion are discussed.

Abstract

In Randall-Sundrum models, one typically expects the radion to be the lightest new "gravity" state, as it is dual to a composite pseudo-Goldstone boson associated with conformal symmetry breaking in the IR. Here, we investigate the effects of localized brane curvature on the properties of the radion in Goldberger-Wise stabilized Randall-Sundrum models. We point out that both the radion mass and coupling to brane matter are sensitive to the brane curvature. Radion/Higgs kinetic mixing, via an IR-localized non-minimal coupling to the Higgs, is also investigated, in relation to the ghost-like radion that can occur for $\mathcal{O}(10)$ values of the IR curvature (as required to significantly suppress the first Kaluza-Klein graviton mass). We also discuss a class of speculative IR localized terms involving the radion. Basic comments regarding the dual 4D theory are offered.