Higgs portal vector dark matter for $\mathinner{\mathrm{GeV}}$ scale $\gamma$-ray excess from galactic center

TL;DR

This paper proposes a Higgs portal vector dark matter model that explains the GeV gamma-ray excess from the galactic center through dark matter annihilation into dark Higgs bosons, which decay into standard model particles.

Contribution

It introduces a renormalizable Abelian vector dark matter model with a flavor-dependent Higgs portal that accounts for the gamma-ray excess and is testable by upcoming direct detection experiments.

Findings

The model can explain the GeV gamma-ray excess via dark matter annihilation.

Some parameter space is accessible to future direct detection experiments.

The scenario is consistent with current observational constraints.

Abstract

We show that the $\mathinner{\mathrm{GeV}}$ scale $\gamma$-ray excess from the direction of the Galactic Center can be naturally explained by the pair annihilation of Abelian vector dark matter (VDM) into a pair of dark Higgs bosons $VV \rightarrow \phi \phi$, followed by the subsequent decay of $\phi$ into $\phi \rightarrow b\bar{b} , \tau \bar{\tau} $. All the processes are described by a renormalizable VDM model with the Higgs portal, which is naturally flavor-dependent. Some parameter space of this scenario can be tested at the near future direct dark matter search experiments such as LUX and XENON1T.