Physical parameters and basis transformations in the Two-Higgs-Doublet model

TL;DR

This paper establishes a direct link between the physical parameters of the Two-Higgs-Doublet Model after electroweak symmetry breaking and the parameters before symmetry breaking, highlighting basis transformation properties and potential implications.

Contribution

It provides explicit relations and a basis covariant formulation connecting pre- and post-EWSB parameters in the 2HDM, clarifying basis transformations and their physical significance.

Findings

Relations between physical and potential parameters are explicitly derived.

Basis transformation properties of Higgs mass matrices are characterized.

Potential can sometimes be expressed solely in terms of physical parameters.

Abstract

A direct connection between physical parameters of general Two-Higgs-Doublet Model (2HDM) potentials after electroweak symmetry breaking (EWSB) and the parameters that define the potentials before EWSB is established. These physical parameters, such as the mass matrix of the neutral Higgs bosons, have well defined transformation properties under basis transformations transposed to the fields after EWSB. The relations are also explicitly written in a basis covariant form. Violation of these relations may indicate models beyond 2HDMs. In certain cases the whole potential can be defined in terms of the physical parameters. The distinction between basis transformations and reparametrizations is pointed out. Some physical implications are discussed.