An Introduction to 5-Dimensional Extensions of the Standard Model

TL;DR

This paper introduces the physics of large extra dimensions, focusing on minimal Standard Model extensions with gauge fields in a compact fifth dimension, discussing theoretical techniques and phenomenological bounds from experimental data.

Contribution

It provides a pedagogical overview of 5D Standard Model extensions, including gauge fixing, model extensions, and phenomenological bounds from current data.

Findings

Bounds on compactification scale between 4 and 6 TeV

Techniques for extending Standard Model to 5D

Analysis of gauge field propagation effects

Abstract

We give a pedagogical introduction to the physics of large extra dimensions. We focus our discussion on minimal extensions of the Standard Model in which gauge fields may propagate in a single, compact extra dimension while the fermions are restricted to a 4-dimensional Minkowski subspace. First, the basic ideas, including an appropriate gauge-fixing procedure in the higher-dimensional context, are illustrated in simple toy models. Then, we outline how the presented techniques can be extended to more realistic theories. Finally, we investigate the phenomenology of different minimal Standard Model extensions, 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. Bounds on the compactification scale between 4 and 6 TeV, depending on the model, are established by analyzing existing data.