Symmetries and renormalisation in two-Higgs-doublet models

TL;DR

This paper classifies symmetries in two-Higgs-doublet models, introduces a maximally-CP-symmetric model, studies its parameter evolution, and identifies viable Higgs mass ranges for LHC detection.

Contribution

It provides a practical method for identifying symmetry classes in THDM and extends CP symmetry to Yukawa sectors, leading to the MCPM with testable predictions.

Findings

Identified symmetry classes and groups in THDM potentials.

Developed a method to determine symmetry class of a given potential.

Found viable Higgs mass ranges up to several hundred GeV for LHC detection.

Abstract

We discuss the classification of symmetries and the corresponding symmetry groups in the two-Higgs-doublet model (THDM). We give an easily useable method how to determine the symmetry class and corresponding symmetry group of a given THDM Higgs potential. One of the symmetry classes corresponds to a Higgs potential with several simultaneous generalised CP symmetries. Extending the CP symmetry of this class to the Yukawa sector in a straightforward way, the so-called maximally-CP-symmetric model (MCPM) is obtained. We study the evolution of the quartic Higgs-potential parameters under a change of renormalisation point. Finally we compute the so called oblique parameters S, T, and U, in the MCPM and we identify large regions of viable parameter space with respect to electroweak precision measurements. We present the corresponding allowed regions for the masses of the physical Higgs bosons. Reasonable ranges for these masses, up to several hundred GeV, are obtained which should make the (extra) Higgs bosons detectable in LHC experiments.