Gauge bosons in a five-dimensional theory with localized gravity

TL;DR

The paper investigates gauge bosons propagating in a warped five-dimensional AdS slice with two 4D boundaries, focusing on the KK decomposition, mass spectrum, and boundary couplings. It finds that the massless bulk gauge mode is not localized, unlike gravitons, and that KK excitations acquire TeV-scale masses with sizable couplings to the π-boundary and non-negligible couplings to the 0-boundary. For massive 5D gauge bosons, the KK modes couple weakly to the 0-boundary while maintaining strong couplings to the π-boundary. The results have potential implications for Standard Model gauge bosons, electroweak precision tests, and GUT-related physics in warped extra-dimensional setups.

Abstract

We consider the possibility of gauge bosons living in the recently proposed five-dimensional theory with localized gravity. We study the mass spectrum of the Kaluza-Klein (KK) excitations of the gauge fields and calculate their couplings to the boundaries of the fifth dimension. We find a different behaviour from the case of the graviton. In particular, we find that the massless mode is not localized in the extra dimension and that the KK excitations have sizeable couplings to the two boundaries. We also discuss possible phenomenological implications for the case of the standard model gauge bosons.