The general Two-Higgs doublet eXtensions of the SM: a saucerful of secrets

Understand

We discuss the most general formulation of the Two-Higgs doublet model, which incorporates flavor changing neutral scalar interactions (FCNSI) and CP violation (CPV) from several sources.

• CP violation can arise either from Yukawa terms or from the Higgs potential, be it explicit or spontaneous.
• We show how the model, which is denoted as 2HDM-X, reduces to some versions known in the literature (2HDM-I,II,III), as well as some of their variants (top, lepton, dark) denoted here as 2HDM-IV.
• We also discuss another limit that includes CPV and Yukawa four textures to control FCNSI, which we denote as 2HDM-V.