Dark matter in the Inert Doublet Model after the discovery of a Higgs-like boson at the LHC

TL;DR

This paper analyzes the Inert Doublet Model post-Higgs discovery, focusing on dark matter properties, theoretical constraints, and collider phenomenology, including relic density calculations, direct detection issues, and Higgs decay predictions.

Contribution

It provides a comprehensive update on the Inert Doublet Model incorporating one-loop corrections, improved relic density calculations, and new benchmark points considering LHC constraints.

Findings

Constraints on model parameters consistent with a 126 GeV Higgs

Potential enhancement of h -> γγ decay rate from charged inert scalar

Dark matter relic density compatible with observations under certain conditions

Abstract

We examine the Inert Doublet Model in light of the discovery of a Higgs-like boson with a mass of roughly 126 GeV at the LHC. We evaluate one-loop corrections to the scalar masses and perform a numerical solution of the one-loop renormalization group equations. Demanding vacuum stability, perturbativity, and S-matrix unitarity, we compute the scale up to which the model can be extrapolated. From this we derive constraints on the model parameters in the presence of a 126 GeV Higgs boson. We perform an improved calculation of the dark matter relic density with the Higgs mass fixed to the measured value, taking into account the effects of three- and four-body final states resulting from off-shell production of gauge bosons in dark matter annihilation. Issues related to direct detection of dark matter are discussed, in particular the role of hadronic uncertainties. The predictions for the interesting decay mode h ->\gamma \gamma\ are presented for scenarios which fulfill all model constraints, and we discuss how a potential enhancement of this rate from the charged inert scalar is related to the properties of dark matter in this model. We also apply LHC limits on Higgs boson decays to invisible final states, which provide additional constraints on the mass of the dark matter candidate. Finally, we propose three benchmark points that capture different aspects of the relevant phenomenology.