Bulk Gauge Fields in the Randall-Sundrum Model

TL;DR

Placing Standard Model gauge fields in the bulk of the Randall-Sundrum model leads to strong coupling issues and conflicts with experimental constraints, making it incompatible with the model's current formulation.

Contribution

This paper analyzes the implications of bulk gauge fields in the Randall-Sundrum model and shows it results in theoretical and experimental inconsistencies.

Findings

KK excitations are strongly coupled

Electroweak data constrain lowest states above 23 TeV

Model parameters imply bulk curvature exceeds Planck scale

Abstract

We explore the consequences of placing the Standard Model gauge fields in the bulk of the recently proposed localized gravity model of Randall and Sundrum. We find that the Kaluza Klein excitations of these fields are necessarily strongly coupled and we demonstrate that current precision electroweak data constrain the lowest states to lie above $\simeq 23$ TeV. Taking the weak scale to be $\sim 1$ TeV, the resulting implications on the model parameters force the bulk curvature, $R_5$, to be larger than the higher dimensional Planck scale, $M$, violating the consistency of the theory. In turn, to preserve $|R_5|\lsim M^2$, the weak scale must be pushed to $\gsim 100$ TeV. Hence we conclude that it is disfavored to place the Standard Model gauge fields in the bulk of this model as it is presently formulated.