Anomalous Higgs Interactions in Gauge-Higgs Unification

TL;DR

This paper explores how gauge-Higgs unification leads to periodic and non-linear Higgs interactions, affecting Yukawa couplings and Higgs stability, with implications for deviations from the Standard Model in a 5D framework.

Contribution

It provides a detailed analysis of anomalous Higgs interactions in gauge-Higgs unification, reconciling linear gauge interactions with non-linear Yukawa couplings and examining stability mechanisms.

Findings

Yukawa couplings exhibit periodic and non-linear behavior.

In certain VEV choices, Yukawa coupling of KK zero mode fermion vanishes.

Higgs interactions with W and Z bosons match Standard Model predictions except at specific VEVs.

Abstract

We discuss anomalous Higgs interactions in the scenario of gauge-Higgs unification. In the scenario Higgs originates from higher dimensional gauge field and has a physical meaning as AB phase or Wilson loop. As its inevitable consequence, physical observables are expected to be periodic in the Higgs field. In particular, the Yukawa coupling is expected to show some periodic and non-linear behavior as the function of the Higgs VEV. For a specific choice of the VEV, the Yukawa coupling of KK zero mode fermion even vanishes. On the other hand, the Yukawa coupling is originally provided by gauge interaction, which is linear in the Higgs field. We discuss how such two apparent contradiction about the non-linearity of the Yukawa coupling can be reconciled and at the same time how these two "pictures" give different predictions in the simplest framework of the scenario: SU(3) electroweak model in 5-dimensional flat space-time with orbifolding. The deviation of the Yukawa coupling from the standard model prediction is also calculated for arbitrary VEV. We study "$H$-parity", which guarantees the stability of the Higgs for a specific choice of the VEV. Also discussed is the Higgs interaction with $W^\pm$ and $Z^0$. It turns out that in our framework of flat space-time the interaction does not show deviation from the standard model prediction, except for the specific case of the VEV.