Dark Matter Complementarity and the Z$^\prime$ Portal

TL;DR

This paper uses multiple experimental constraints to tightly limit the parameter space of Z' gauge bosons as dark matter mediators, excluding most scenarios that produce the correct relic abundance.

Contribution

It provides a comprehensive analysis of Z' portal models, deriving robust bounds from collider, direct, indirect detection, and muon magnetic moment data, significantly narrowing viable parameter space.

Findings

Mediators lighter than 2.1 TeV are excluded regardless of dark matter mass.

Most of the parameter space producing the correct relic abundance is ruled out.

Heavier Z' masses are required depending on coupling strength to satisfy relic and experimental constraints.

Abstract

Z' gauge bosons arise in many particle physics models as mediators between the dark and visible sectors. We exploit dark matter complementarity and derive stringent and robust collider, direct and indirect constraints, as well as limits from the muon magnetic moment. We rule out almost the entire region of the parameter space that yields the right dark matter thermal relic abundance, using a generic parametrization of the Z'-fermion couplings normalized to the Standard Model Z-fermion couplings for dark matter masses in the 8 GeV-5 TeV range. We conclude that mediators lighter than 2.1 TeV are excluded regardless of the DM mass, and that depending on the Z'-fermion coupling strength much heavier masses are needed to reproduce the DM thermal relic abundance while avoiding existing limits.