SM Kaluza-Klein Excitations and Electroweak Precision Tests

TL;DR

This paper investigates a minimal higher-dimensional extension of the Standard Model with one compactified dimension, analyzing its compatibility with electroweak precision data from various experiments.

Contribution

It provides a comprehensive analysis of electroweak tests on Kaluza-Klein excitations in a minimal higher-dimensional Standard Model extension.

Findings

Atomic parity violation and neutrino scattering data strongly restrict model parameters.

Low-energy data are incompatible at 95% CL with high-energy experimental restrictions.

Global fit indicates a poor overall agreement with all data sets.

Abstract

We consider a minimal extension to higher dimensions of the Standard Model, having one compactified dimension, and we study its experimental tests in terms of electroweak data. We discuss tests from high-energy data at the $Z$-pole, and low-energy tests, notably from atomic parity violation data. This measurement combined with neutrino scattering data strongly restricts the allowed region of the model parameters. Furthermore this region is incompatible at 95% CL with the restrictions from high-energy experiments. Of course a global fit to all data is possible but the $\chi^2_{\rm min}$ for degree of freedom is unpleasantly large.