Dynamical Electroweak Symmetry Breaking in SO(5)xU(1) Gauge-Higgs Unification with Top and Bottom Quarks

TL;DR

This paper develops a gauge-Higgs unification model in warped space that explains electroweak symmetry breaking and predicts a light Higgs boson mass, evading LEP2 bounds through specific boundary conditions and the Hosotani mechanism.

Contribution

It constructs a novel SO(5)xU(1) gauge-Higgs unification model incorporating top and bottom quarks with specific boundary conditions, predicting Higgs properties and symmetry breaking.

Findings

Higgs mass predicted around 50 GeV for certain warp factors

Electroweak symmetry breaking triggered by gauge couplings of top quarks

Higgs couplings to W and Z vanish, evading LEP2 bounds

Abstract

An SO(5)xU(1) gauge-Higgs unification model in the Randall-Sundrum warped space with top and bottom quarks is constructed. Additional fermions on the Planck brane make exotic particles heavy by effectively changing boundary conditions of bulk fermions from those determined by orbifold conditions. Gauge couplings of a top quark multiplet trigger electroweak symmetry breaking by the Hosotani mechanism, simultaneously giving a top quark the observed mass. The bottom quark mass is generated by combination of brane interactions and the Hosotani mechanism, where only one ratio of brane masses is relevant when the scale of brane masses is much larger than the Kaluza-Klein scale (\sim 1.5 TeV). The Higgs mass is predicted to be 49.9 (53.5) GeV for the warp factor 10^{15} (10^{17}). The Wilson line phase turns out \pi/2 and the Higgs couplings to W and Z vanish so that the LEP2 bound for the Higgs mass is evaded. In the flat spacetime limit the electroweak symmetry is unbroken.