Modulus stabilization and IR-brane kinetic terms in gauge-Higgs unification

TL;DR

This paper investigates how IR-brane kinetic terms influence modulus stabilization and gauge couplings in a warped gauge-Higgs unification model, finding that moderate brane terms are necessary but can affect KK mode masses and couplings.

Contribution

It demonstrates the necessity of brane kinetic terms with O(1) coefficients for modulus stabilization and explores their effects on gauge couplings and KK mode masses in the model.

Findings

Brane kinetic terms are essential for modulus stabilization.

Large brane kinetic terms can alter gauge couplings and KK masses.

KK gluon mass is below 1 TeV, near experimental bounds.

Abstract

We discuss the modulus stabilization by the Casimir energy and various effects of IR-brane kinetic terms for the gauge fields in a gauge-Higgs unification model in the warped spacetime, where the Wilson line phase $\theta_H$ is determined as $\theta_H=\pi/2$. We find that the brane kinetic terms with O(1) coefficients are necessary for the modulus stabilization. On the other hand, large brane kinetic terms can deviate 4D gauge couplings from the standard model values and also cause too light Kaluza-Klein (KK) modes. In the parameter region that ensures the modulus stabilization, the KK gluon appears below 1 TeV, which marginally satisfies the experimental bound. The allowed parameter region will be enlarged in a model where a smaller value of $\theta_H$ is realized.