A new viable region of the inert doublet model

TL;DR

This paper identifies a new viable parameter space in the inert doublet model for dark matter with masses between Mw and 160 GeV, where relic density is achieved through diagram cancellations, and discusses detection prospects.

Contribution

It reveals a previously overlooked viable region in the inert doublet model, explaining the cancellation mechanisms and analyzing detection prospects.

Findings

New viable dark matter mass region identified between Mw and 160 GeV.

Cancellations between diagrams enable correct relic density in this region.

Future direct detection experiments can probe the entire new parameter space.

Abstract

The inert doublet model, a minimal extension of the Standard Model by a second Higgs doublet, is one of the simplest and most attractive scenarios that can explain the dark matter. In this paper, we demonstrate the existence of a new viable region of the inert doublet model featuring dark matter masses between Mw and about 160 GeV. Along this previously overlooked region of the parameter space, the correct relic density is obtained thanks to cancellations between different diagrams contributing to dark matter annihilation into gauge bosons (W+W- and ZZ). First, we explain how these cancellations come about and show several examples illustrating the effect of the parameters of the model on the cancellations themselves and on the predicted relic density. Then, we perform a full scan of the new viable region and analyze it in detail by projecting it onto several two-dimensional planes. Finally, the prospects for the direct and the indirect detection of inert Higgs dark matter within this new viable region are studied. We find that present direct detection bounds already rule out a fraction of the new parameter space and that future direct detection experiments, such as Xenon100, will easily probe the remaining part in its entirety.