# Scalar dark matter coannihilating with a coloured fermion

## TL;DR

This paper investigates a scalar dark matter model interacting via a coloured fermion, employing non-perturbative effects to refine relic abundance predictions and confronts these with current and future experimental constraints.

## Contribution

It introduces a non-relativistic effective field theory approach to include Sommerfeld and bound-state effects in dark matter coannihilation analysis.

## Key findings

- Dark matter masses up to 18 TeV are excluded by XENON1T.
- Future experiments could probe most remaining parameter space.
- Non-perturbative effects significantly impact relic abundance calculations.

## Abstract

We analyse the phenomenology of a simplified model for a real scalar dark matter candidate interacting with quarks via a coloured fermionic mediator. In the coannihilation regime, the dark matter abundance is controlled by the dynamics of the coloured fermions which can be significantly affected by non-perturbative effects. We employ a non-relativistic effective field theory approach which allows us to systematically treat the Sommerfeld effect and bound-state formation in the early Universe. The parameter space compatible with the dark matter relic abundance is confronted with direct, indirect and collider searches. A substantial part of the parameter space, with dark matter masses up to 18 TeV, is already excluded by XENON1T. Most of the remaining thermal relics can be probed by a future Darwin-like experiment, when taking properly into account the running of the relevant couplings for the direct detection processes.