Signatures from Scalar Dark Matter with a Vector-like Quark Mediator

TL;DR

This paper explores a scalar dark matter model interacting via a vector-like quark mediator, analyzing its relic abundance, detection prospects, and collider signatures, highlighting unique annihilation channels and viable mass ranges.

Contribution

It provides a detailed analysis of scalar dark matter coupled through a vector-like quark, including novel annihilation mechanisms and experimental constraints.

Findings

Dark matter annihilates into gluons at one-loop and via gluon bremsstrahlung.

Viable dark matter masses are near the mediator or above 2 TeV.

Detection prospects depend on mass degeneracy and coupling strengths.

Abstract

We present a comprehensive study of a model where the dark matter is composed of a singlet real scalar that couples to the Standard Model predominantly via a Yukawa interaction with a light quark and a colored vector-like fermion. A distinctive feature of this scenario is that thermal freeze-out in the early universe may be driven by annihilation both into gluon pairs at one-loop ($gg$) and by virtual internal Bremsstrahlung of a gluon ($q \bar{q} g$). Such a dark matter candidate may also be tested through direct and indirect detection and at the LHC; viable candidates have either a mass nearly degenerate with that of the fermionic mediator or a mass above about 2 TeV.