Electroweak Constraints on Extended Models with Extra Dimensions

TL;DR

This paper analyzes how electroweak measurements constrain models with extra dimensions, especially considering various matter field configurations and gauge group assignments, finding bounds on the compactification scale between 1.5 and 4 TeV.

Contribution

It provides a comprehensive analysis of electroweak constraints on extended extra-dimensional models, including scenarios with bulk matter and different gauge group assignments, which was not thoroughly explored before.

Findings

Bounds on compactification scale between 1.5 and 4 TeV

Constraints vary with matter field propagation in the bulk

Models with different gauge group assignments can relax bounds

Abstract

Electroweak measurements place significant bounds on higher-dimensional versions of the standard model in which the gauge and Higgs fields have Kaluza-Klein excitations. These bounds may be altered quantitatively if chiral matter is also allowed to propagate in the higher-dimensional `bulk'. We determine the electroweak constraints on a number of models of this type, including scenarios in which only the leptons or only the first two generations of matter fields propagate in the bulk. We also consider the possibility that different factors of the electroweak gauge group may be distinguished by their bulk/three-brane assignment, and study a minimal extra-dimensional Z' model. We find typical bounds on the compactification scale between 1.5 and 4 TeV, and comment on models in which these bounds might be significantly relaxed.