Universal Properties of Pseudoscalar Mediators

TL;DR

This paper identifies universal collider signals of pseudoscalar mediators in Dark Matter models, emphasizing the mono-Z channel as the most promising detection signature across various consistent simplified models.

Contribution

It introduces a universality class of simplified pseudoscalar mediator models with renormalizable couplings, analyzing their constraints and collider signatures.

Findings

Mono-Z final state is the strongest universal signal.

Constraints from stability, perturbativity, and electroweak precision are considered.

Additional signatures can distinguish different ultraviolet completions.

Abstract

We discuss universal signals of consistent models of pseudoscalar mediators for collider searches for Dark Matter. Keeping only the degrees of freedom that can not be decoupled due to consistency conditions, we present a universality class of simplified models with pseudoscalar mediators and renormalizable couplings to Standard Model fields. We compute stability and perturbativity constraints, constraints from electroweak precision measurements, collider searches for new heavy particles as well as constraints from relic density measurements and indirect detection experiments searching for signals of Dark Matter annihilation into photons. We find that the mono-$Z$ final state is the strongest, universal signal of this class of models, with additional signatures present in the different ultraviolet completions that can be used to distinguish between them.