Simplified Dirac Dark Matter Models and Gamma-Ray Lines

TL;DR

This paper explores simplified Dirac fermion dark matter models with a new gauge symmetry, analyzing their annihilation signals, especially gamma-ray lines, and connecting collider and dark matter experimental constraints.

Contribution

It introduces a minimal Dirac dark matter model under B-L gauge symmetry and provides detailed analytical predictions for gamma-ray line signals.

Findings

Annihilation into gamma-ray lines is not velocity suppressed.

Analytical formulas applicable to any Abelian gauge charged Dirac dark matter.

Numerical analysis within the B-L model shows viable parameter space.

Abstract

We investigate simplified dark matter models where the dark matter candidate is a Dirac fermion charged only under a new gauge symmetry. In this context one can understand dynamically the stability of the dark matter candidate and the annihilation through the new gauge boson is not velocity suppressed. We present the simplest Dirac dark matter model charged under the local B-L gauge symmetry. We discuss in great detail the theoretical predictions for the annihilation into two photons, into the Standard Model Higgs and a photon, and into the Z gauge boson and a photon. Our analytical results can be used for any Dirac dark matter model charged under an Abelian gauge symmetry. The numerical results are shown in the B-L dark matter model. We discuss the correlation between the constraints on the model from collider searches and dark matter experiments.