Fermion Portal Dark Matter

TL;DR

This paper analyzes simplified fermion portal dark matter models, highlighting how collider and direct detection experiments complement each other in probing different parameter space regions, and proposing dedicated search strategies.

Contribution

It provides a comprehensive comparison of collider and direct detection sensitivities for Majorana, Dirac, and complex dark matter within fermion portal models, and suggests new search strategies.

Findings

Direct detection covers near degeneracy regions for Majorana dark matter.

Colliders are sensitive to large mass splittings and light dark matter.

Dedicated jet and mono-jet searches can probe remaining parameter space.

Abstract

We study a class of simplified dark matter models in which one dark matter particle couples with a mediator and a Standard Model fermion. In such models, collider and direct detection searches probe complimentary regions of parameter space. For Majorana dark matter, direct detection covers the region near mediator-dark matter degeneracy, while colliders probe regions with a large dark matter and mediator mass splitting. For Dirac and complex dark matter, direct detection is effective for the entire region above the mass threshold, but colliders provide a strong bound for dark matter lighter than a few GeV. We also point out that dedicated searches for signatures with two jets or a mono-jet not coming from initial state radiation, along missing transverse energy can cover the remaining parameter space for thermal relic dark matter.