Relic density of dark matter in the inert doublet model beyond leading order for the low mass region: 2. Co-annihilation

TL;DR

This paper calculates precise one-loop electroweak corrections to dark matter relic density in the inert doublet model, focusing on co-annihilation processes in the low mass region, revealing new scalar self-interaction effects.

Contribution

It provides the first detailed one-loop electroweak correction analysis for co-annihilation in the IDM, including effects on subdominant processes and scalar self-interactions.

Findings

Electroweak corrections are well approximated by an effective cross-section.

Subdominant annihilation processes depend on scalar self-interaction parameters.

Corrections significantly impact relic density calculations in the low mass region.

Abstract

We examine the relic density of the light mass dark matter region in the inert doublet model (IDM) when the dominant process is due to co-annihilation between the lightest neutral scalars of the model. The full one-loop electroweak corrections are computed in an on-shell scheme and are found to be well approximated as an effective cross-section expressed in terms of $Z$-observables. The electroweak corrections to the subdominant process which consists of an annihilation into an on-shell $W$ and an off-shell $W$, that is calculated as a annihilation into a 3-body final state, is also performed. The latter reveals an important dependence on a parameter that describes the self-interaction of the new scalars (solely within the dark sector), a parameter which is not accessible in tree-level calculations of standard model (SM)-IDM interactions.