Light states in real 3HDMs with spontaneous CP violation and softly broken symmetries

TL;DR

This paper investigates the scalar sector of three-Higgs-doublet models with spontaneous CP violation, revealing that new scalars are constrained to be near the electroweak scale despite large quadratic terms.

Contribution

It provides a detailed analysis of light scalar states in 3HDMs with CP violation and discrete symmetries, combining analytic and numerical results.

Findings

New scalars cannot be much heavier than the electroweak scale under perturbativity.

Analytic and numerical analyses illustrate the scalar mass spectrum constraints.

Phenomenological implications are derived from scalar sector properties alone.

Abstract

Scalar sectors with several Higgs doublets, a CP invariant potential, and a CP violating vacuum, possess a mass spectrum in which, unexpectedly, new scalars cannot have masses much larger than the electroweak scale once perturbativity requirements are imposed on the quartic couplings of the Higgs potential and despite the presence of free quadratic (mass) terms that can be arbitrarily large. The minimal model in which this behavior is manifest involves 3 Higgs doublets. We analyze and illustrate in detail that kind of scenario including an additional simplifying assumption: the quartic part of the potential is shaped by some discrete symmetry. Besides analytic results, a numerical analysis is presented together with some phenomenological consequences derived only from the properties of the scalar sector alone.