Leptonic WIMP Coannihilation and the Current Dark Matter Search Strategy

TL;DR

This paper evaluates the potential of future high-energy and astroparticle experiments to probe WIMP dark matter models, especially focusing on coannihilation effects and the limitations for Majorana dark matter detection.

Contribution

It provides a comprehensive analysis of the sensitivity of upcoming experiments to coannihilating WIMP models, highlighting the gaps in current detection capabilities for Majorana dark matter.

Findings

Perturbative models can explain relic abundance up to 10 TeV.

Current and future experiments can probe Dirac DM up to 10 TeV.

Majorana DM remains largely unconstrained above 2-4 TeV.

Abstract

We discuss the extent to which models of Weakly Interacting Massive Particle (WIMP) Dark Matter (DM) at and above the electroweak scale can be probed conclusively in future high energy and astroparticle physics experiments. We consider simplified models with bino-like dark matter and slepton-like coannihilation partners, and find that perturbative models yield the observed relic abundance up to at least 10 TeV. We emphasise that coannihilation can either increase or decrease the dark matter relic abundance. We compute the sensitivity of direct detection experiments to DM-nucleus scattering, consider indirect detection bounds and estimate the sensitivity of future proton colliders to slepton pair production. We find that current and future experiments will be able to probe the Dirac DM models up to at least 10 TeV. However, current and future searches will not be sensitive to models of Majorana dark matter for masses above 2 or 4 TeV, for one or ten coannihilation partners respectively, leaving around 70 % of the parameter space unconstrained. This demonstrates the need for new experimental ideas to access models of coannihilating Majorana dark matter.