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Abstract

We investigate possible extensions of the Standard Model according to either elementary or composite nature of the Higgs boson. In the former scenario, we present a model of flavored axion Higgs unification in which electroweak symmetry breaking occurs dynamically and selects a small region for the axion decay constant that will be fully tested at forthcoming dark matter and flavor experiments. Moreover, if the Higgs is elementary, yukawa couplings are regarded as fundamental interactions: this relates to possible UV completions based on asymptotic safety for which we provide new insights by studying models containing a large multiplicity of fermion fields. Finally, we introduce a new realization of a composite Higgs that resolves the tension with null-signals of new physics at the LHC. It is based on a new symmetry structure that we call soft breaking, whose realization in the context of a warped extra dimension is particularly simple. When combined with other possible symmetries this allows for a completely natural model to emerge predicting composite resonances above 2 TeV with fine-tuning at the minimum 10% already implied by LEP and thus restoring naturalness in the light of the LHC data.