Two Higgs doublets model in gauge-Higgs unification framework

We discuss the realization of a two Higgs doublets model in the framework of a six-dimensional gauge-Higgs unification model with a simple Lie group G_M. Two Higgs SU(2)_L doublets can emerge at the low energy effective theory, and the quartic coupling terms in the scalar potential, which are essential for the electroweak symmetry breaking, are now G_M gauge invariant and permissive. A realistic two Higgs doublets model can possibly be obtained only when two of the root vectors associated with the would-be Higgs doublets and the root vector for SU(2)_L form an isosceles triangle with a vertex angle either of π/3, π/2, or 2π/3. Moreover, depending on G_M, the scalar potential of the resulting two Higgs doublets model can admit only a few limited forms. The mass spectrum of the physical Higgs and the weak mixing angle are briefly discussed.