A possible minimal gauge-Higgs unification

TL;DR

This paper presents a minimal gauge-Higgs unification model in higher dimensions, successfully reproducing the standard model features and predicting a Z' boson with specific mass constraints.

Contribution

It constructs a novel minimal gauge-Higgs unification model with detailed symmetry breaking and anomaly cancellation mechanisms.

Findings

Predicts a Z' boson with mass between 2.7 and 13.6 TeV.

Constrains the compactification scale between 40 and 200 TeV.

Provides a framework for small neutrino masses via seesaw mechanism.

Abstract

A possible minimal model of the gauge-Higgs unification based on the higher dimensional spacetime M^4 X (S^1/Z_2) and the bulk gauge symmetry SU(3)_C X SU(3)_W X U(1)_X is constructed in some details. We argue that the Weinberg angle and the electromagnetic current can be correctly identified if one introduces the extra U(1)_X above and a bulk scalar triplet. The VEV of this scalar as well as the orbifold boundary conditions will break the bulk gauge symmetry down to that of the standard model. A new neutral zero-mode gauge boson Z' exists that gains mass via this VEV. We propose a simple fermion content that is free from all the anomalies when the extra brane-localized chiral fermions are taken into account as well. The issues on recovering a standard model chiral-fermion spectrum with the masses and flavor mixing are also discussed, where we need to introduce the two other brane scalars which also contribute to the Z' mass in the similar way as the scalar triplet. The neutrinos can get small masses via a type I seesaw mechanism. In this model, the mass of the Z' boson and the compactification scale are very constrained as respectively given in the ranges: 2.7 TeV < m_Z' < 13.6 TeV and 40 TeV < 1/R < 200 TeV.