Collider Signatures of Gauge-Higgs Unification at LHC

TL;DR

This paper investigates how Kaluza-Klein modes in a five-dimensional gauge-Higgs unification model affect Higgs diphoton decay at the LHC, revealing destructive interference with the Standard Model and unique features in Z gamma decay.

Contribution

It provides the first detailed analysis of KK mode effects on Higgs diphoton and Z gamma decays within a 5D GHU model, including extensions to match experimental data.

Findings

KK modes cause destructive interference in diphoton decay

Extensions can enhance diphoton decay and achieve correct Higgs mass

No KK contributions to Z gamma decay at 1-loop level

Abstract

We have studied the Kaluza-Klein (KK) mode contributions to the diphoton decay of Higgs boson through the gluon fusion at LHC in a five dimensional $SU(3) times U(1)'$ gauge-Higgs unification (GHU) model. The minimal matter content case is found that the diphoton decay is necessarily destructive comparing to the Standard Model (SM) prediction, which is unfortunately not supported by the current experimental data. Two extensions are considered to not only enhance the diphoton decay but also realize an observed Higgs mass. The $Z gamma$ decay of Higgs boson is also studied and the striking result is found that there is no KK mode contributions to the decay at 1-loop level. This fact might be very useful to discriminate the GHU from other physics beyond the SM.