Gauge-Higgs Unification and Quark-Lepton Phenomenology in the Warped Spacetime

Abstract

In the dynamical gauge-Higgs unification of electroweak interactions in the Randall-Sundrum warped spacetime the Higgs boson mass is predicted in the range 120 GeV -- 290 GeV, provided that the spacetime structure is determined at the Planck scale. Couplings of quarks and leptons to gauge bosons and their Kaluza-Klein (KK) excited states are determined by the masses of quarks and leptons. All quarks and leptons other than top quarks have very small couplings to the KK excited states of gauge bosons. The universality of weak interactions is slightly broken by magnitudes of $10^{-8}$, $10^{-6}$ and $10^{-2}$ for $\mu$-$e$, $\tau$-$e$ and $t$-$e$, respectively. Yukawa couplings become substantially smaller than those in the standard model, by a factor $|\cos \onehalf \theta_W|$ where $\theta_W$ is the non-Abelian Aharonov-Bohm phase (the Wilson line phase) associated with dynamical electroweak symmetry breaking.