Vacuum (in)stability in 2HDMS vs N2HDM

TL;DR

This paper compares vacuum stability criteria in two extended scalar sector models, N2HDM and 2HDMS, analyzing their differences and implications for scalar couplings and dark matter viability.

Contribution

It provides a detailed comparison of vacuum stability conditions in N2HDM and 2HDMS, including the impact of scalar couplings and dark matter constraints.

Findings

Vacuum stability constraints differ between models.

Scalar coupling measurements can distinguish models.

Dark matter viability affects stability conditions.

Abstract

In this work, we examine the criteria for vacuum stability in two models with extended scalar sectors namely, the N2HDM and the 2HDMS and make a detailed comparison between the two. For the purpose of demonstration, we choose a scenario which can accommodate the recently observed 95 GeV excess in both models. We further explore the impact of the measurement of the Yukawa couplings, the gauge boson couplings and most importantly the trilinear self-couplings of the scalars, in distinguishing the vacuum structure in both models. We further investigate the constraints from vacuum stability on the 2HDMS scenario that accommodates a viable dark matter candidate and compare it with the N2HDM case.