Vacuum alignment in a composite 2HDM

TL;DR

This paper analyzes the vacuum structure of a composite two Higgs doublet model based on SU(6)/Sp(6) symmetry breaking, identifying conditions for CP conservation and the emergence of a Dark Matter candidate.

Contribution

It provides a detailed study of the vacuum structure in a minimal composite 2HDM with a specific symmetry breaking pattern, including the role of Yukawa alignment and CP conservation.

Findings

Most general CP-conserving vacuum has three non-zero angles.

Aligned Yukawas lead to a single vacuum angle.

A Dark Matter candidate emerges when Yukawas are aligned.

Abstract

We study in detail the vacuum structure of a composite two Higgs doublet model based on a minimal underlying theory with 3 Dirac fermions in pseudo-real representations of the condensing gauge interactions, leading to the SU(6)/Sp(6) symmetry breaking pattern. We find that, independently on the source of top mass, the most general CP-conserving vacuum is characterised by three non-vanishing angles. A special case occurs if the Yukawas are aligned, leading to a single angle. In the latter case, a Dark Matter candidate arises, protected by a global U(1) symmetry.