# Almost Inert Higgs Bosons at the LHC

## TL;DR

This paper investigates a minimal 2 Higgs doublet model with inert-like Higgs bosons, analyzing their production and detection prospects at the LHC, especially at high luminosity, to explore beyond Standard Model physics.

## Contribution

It introduces a scenario with inert Higgs bosons under an approximate $ ext{Z}_2$ symmetry and systematically studies their LHC phenomenology and search strategies.

## Key findings

- Electroweak pair production of inert Higgs bosons is unsuppressed.
- LHC searches can constrain or discover these inert Higgs bosons.
- High luminosity LHC significantly extends the discovery reach.

## Abstract

Non-minimal Higgs sectors are strongly constrained by the agreement of the measured couplings of the 125 GeV Higgs with Standard Model predictions. This agreement can be explained by an approximate $\mathbb{Z}_2$ symmetry under which the additional Higgs bosons are odd. This allows the additional Higgs bosons to be approximately inert, meaning that they have suppressed VEVs and suppressed mixing with the Standard Model Higgs. In this case, single production of the new Higgs bosons is suppressed, but electroweak pair production is unsuppressed. We study the phenomenology of a minimal 2 Higgs doublet model that realizes this scenario. In a wide range of parameters, the phenomenology of the model is essentially fixed by the masses of the exotic Higgs bosons, and can therefore be explored systematically. We study a number of different plausible signals in this model, and show that several LHC searches can constrain or discover additional Higgs bosons in this parameter space. We find that the reach is significantly extended at the high luminosity LHC.