Emergent two-Higgs doublet models

We investigate origin of three features that are often assumed in analysis of two-higgs doublet models: (i) softly broken z 2 symmetry, (ii) cp invariant higgs potential, and (iii) degenerated mass spectra. we extend electroweak gauge symmetry, introducing extra gauge symmetry and extra scalars, and we show that our models effectively derive two-higgs doublet models at low energy which naturally hold the three features. we also find that the models can solve the strong cp problem.