Dark Matter in Anomaly-Free Gauge Extensions

TL;DR

This paper reviews anomaly-free U(1) gauge extensions for dark matter, analyzing their structure, constraints, and collider signatures, proposing improved search strategies and highlighting the importance of scalar modes and kinetic mixing.

Contribution

It provides a comprehensive analysis of anomaly-free U(1) extensions, including kinetic mixing effects, collider search improvements, and scalar mediator strategies for dark matter detection.

Findings

Shape analysis significantly improves LHC mono-jet searches.

Direct detection limits constrain kinetic mixing angles.

Scalar and vector masses are suggested to be similar by relic density considerations.

Abstract

A consistent model for vector mediators to dark matter needs to be anomaly-free and include a scalar mode from mass generation. For the leading U(1) extensions we review the structure and constraints, including kinetic mixing at loop level. The thermal relic density suggests that the vector and scalar masses are similar. For the LHC we combine a $Z'$ shape analysis with mono-jets. For the latter, we find that a shape analysis offers significant improvement over existing cut-and-count approaches. Direct detection limits strongly constrain the kinetic mixing angle and we propose a $\ell^+\ell^- E_T$ search strategy based on the scalar mediator.