Electroweak Constraints on Minimal Higher-Dimensional Extensions of the Standard Model

Abstract

We derive electroweak constraints on the compactification scale of minimal 5-dimensional extensions of the Standard Model, in which all or only some of the SU(2)${}_L$ and U(1)${}_Y$ gauge fields and Higgs bosons feel the presence of the fifth dimension. In our analysis, we assume that the fermions are always localized on a 3-brane. In this context, we also present the consistent quantization procedure of the higher-dimensional models in the generalized $R_{\xi }$ gauge. We find that the usually derived lower bound of $\sim 4$ TeV on the compactification scale may be significantly lowered to $\sim 3$ TeV if the SU(2)${}_L$ gauge boson is the only particle that propagates in all 5 dimensions.

To appear in the proceedings of the Summer School on High Energy Physics in Corfu, Greece, September 2001