Dark Matter and CP Violation in Some Symmetry-Constrained 3HDMs

TL;DR

This paper investigates dark matter candidates and CP violation in $S_3$-symmetric three-Higgs-doublet models, revealing new mass ranges, symmetry-based stabilization methods, and phenomenological implications for light scalars.

Contribution

It introduces novel dark matter mass ranges, explores continuous symmetry stabilization, and analyzes CP violation effects in $S_3$-symmetric 3HDMs, expanding understanding of symmetry roles in these models.

Findings

Different dark matter mass ranges compared to other 3HDMs

Emergence of mass-degenerate states via continuous symmetries

CP violation effects lead to light neutral scalars

Abstract

Multi-Higgs-doublet models can accommodate a dark matter candidate. An underlying symmetry not only ensures the candidate's stability but also helps control the number of free parameters. We consider two scenarios. First, we explore dark matter candidates in the $S_3$-symmetric three-Higgs-doublet model. Notably, our findings reveal that the cases we discuss allow for different dark matter mass ranges compared to other candidates within three-Higgs-doublet models. Additionally, we investigate an alternative to conventional stabilisation via discrete symmetries by examining stabilisation through continuous symmetries. This alternative approach exhibits a unique characteristic-the emergence of mass-degenerate states. We also explore the impact of CP violation in the $S_3$-symmetric three-Higgs-doublet model. Our analysis investigates how different representations of quarks under the $S_3$ group, combined with various vacuum configurations, lead to distinct phenomenological consequences, including the possibility of very light neutral scalars.