# Minimal renormalizable simplified dark matter model with a pseudoscalar mediator

## TL;DR

This paper introduces a minimal, gauge-invariant dark matter model with a pseudoscalar mediator, highlighting its unique phenomenology, relic density compatibility, and distinguishable collider signatures compared to scalar mediator models.

## Contribution

It presents a novel minimal renormalizable dark matter model with a pseudoscalar mediator and compares its collider phenomenology with scalar mediator models.

## Key findings

- DM can achieve correct relic density and evade direct detection
- Distinctive features in scalar decay and DM production at LHC
- Potential observable signals in indirect detection experiments

## Abstract

We consider a minimal renormalizable and gauge invariant dark matter (DM) model, in which the singlet fermion DM has only axial couplings to a new pseudoscalar mediator. The mixing between the pseudoscalar mediator and the standard model (SM) Higgs boson induces the interactions between the DM and SM particles. The DM candidate in this model can provide the correct thermal relic density and evades all direct detections, while it can produce observable signals in indirect detection experiments due to its large annihilation cross section. A comparative study for DM phenomenology at the LHC is conducted for models with scalar mediators that have either scalar or pseudoscalar couplings to SM particles and the DM. We find that the three scenarios have distinguishable features in scalar decay branching ratio, DM pair production cross section as well as the signal reaches at the LHC. The LHC searches for some visible signals related to the scalar sector are also discussed.