Exploring a Two Higgs Doublet Model with a U(1) Family Symmetry and a Complex Singlet

Abstract: In this project a two Higgs doublet model with a complex singlet and an extra family symmetry providing a mechanism for suppression of flavor changing neutral currents is explored. The goal is to investigate the phenomenological consistency of the model using a custom software framework. To this end, the scalar and Yukawa sectors of this extension of the Standard Model are explored in detail. The corresponding mass spectra, vacuum stability conditions and mixing matrices are presented. An inversion procedure, relating a subset of couplings to physical masses and mixing angles, for both the scalar and the quark Yukawa sector is implemented. In the search for phenomenologically viable parameter space regions, the Higgs alignment limit is relaxed while the Yukawa textures are allowed to take the most general complex values allowed by the symmetries. The phenomenological consistency of the model is investigated in the numerical analysis by comparing candidate points to experimental data from quark flavor violating processes and Higgs searches as well as vetoing any points that do not obey the limits set by electroweak precision observables. To facilitate the numerical analysis, a computer program utilizing several publicly available codes (SARAH, SPheno, HiggsBounds, HiggsSignals, flavio, FlavorKit) is constructed and run on a computer cluster. The results show that a symmetry-induced suppression of the flavor changing neutral currents takes place in the quark sector and the model survives the most stringent phenomenological constraints.