Vector Higgs-portal dark matter and Fermi-LAT gamma ray line

TL;DR

This paper introduces a renormalizable vector dark matter model with an extra U(1) gauge symmetry that explains the Fermi-LAT gamma-ray line at 130 GeV through enhanced annihilation into photons, consistent with experimental constraints.

Contribution

The model uniquely combines a vector dark matter candidate with a singlet scalar and charged scalar to explain gamma-ray signals while satisfying phenomenological bounds.

Findings

Resonance enhancement of dark matter annihilation into photons.

Compatibility with Higgs decay, collider, and stability constraints.

Reproduces the Fermi-LAT gamma-ray line at 130 GeV.

Abstract

We propose a renormalizable model for vector dark matter with extra U(1) gauge symmetry, which is broken by the VEV of a complex singlet scalar. When the singlet scalar has a quartic coupling to a heavy charged scalar, the resonance effect enhances the annihilation cross section of vector dark matter into two photons such that Fermi-gamma ray line at about 130 GeV is obtained. In the presence of a tiny mixing between the singlet scalar and the Standard Model Higgs doublet, the relic density is determined dominantly by WW/ZZ and two-photon channels near the resonance pole of the singlet scalar. We also show that various phenomenological bounds coming from the Higgs to diphoton decay rate, precision data and collider searches for the charged scalar and vacuum stability are satisfied in the model.