H to Z gamma in Gauge-Higgs Unification

TL;DR

This paper examines the effects of Kaluza-Klein modes in gauge-Higgs unification models on Higgs decay channels, revealing a unique prediction that KK modes do not affect the H to Z gamma decay at one loop.

Contribution

It demonstrates that in gauge-Higgs unification, KK modes do not contribute to the H to Z gamma decay at one loop, unlike their effect on H to diphoton decay.

Findings

KK modes enhance Higgs to diphoton coupling

KK modes do not contribute to H to Z gamma at one loop

Potential to distinguish models via decay mode correlations

Abstract

In our previous paper, we have investigated effects of a simple gauge-Higgs unification model on the diphoton signal events from the Higgs boson production at the Large Hadron Collider. We have found that in this model the effective Higgs-to-diphoton coupling can be enhanced by 1-loop corrections with Kaluza-Klein (KK) modes of bulk fields. This result can be an explanation for the observed excess of the signal strength in the Higgs to diphoton decay channel. In this paper, we investigate KK-mode effects on another Higgs boson decay mode, H to Z gamma. One naturally expects that the KK modes also contribute to the effective H-Z-gamma coupling and can cause some deviation for the H to Z gamma decay mode from the Standard Model prediction. Revealing a correlation between the KK-mode effects on the Higgs-to-diphoton and H-Z-gamma couplings is an interesting topic in terms of a possibility to discriminate a variety of models for physics beyond the Standard Model. We show a very striking result for the gauge-Higgs unification model, namely, the absence of KK-mode contributions to the H-Z-gamma coupling at the 1-loop level. This is a very specific and general prediction of the gauge-Higgs unification scenario.