How heavy can dark matter be? Constraining colourful unitarity with SARAH

TL;DR

This paper automates the calculation of unitarity constraints for models with coloured scalars using SARAH, applying it to a dark matter model to derive bounds on dark matter mass.

Contribution

It introduces an automated method for perturbative unitarity constraints with coloured scalars in SARAH, applied to constrain dark matter models.

Findings

Derived bounds on dark matter mass below the Griest-Kamionkowski limit.

Automated unitarity calculations for models with coloured scalars.

Application to a specific dark matter model with coloured mediators.

Abstract

We describe the automation of the calculation of perturbative unitarity constraints including scalars that have colour charges, and its release in SARAH 4.14.4. We apply this, along with vacuum stability constraints, to a simple dark matter model with colourful mediators and interesting decays, and show how it leads to a bound on a thermal relic dark matter mass well below the classic Griest-Kamionkowski limit.