Vector Fermion-Portal Dark Matter: Direct Detection and Galactic Center Gamma-Ray Excess

Understand

We investigate a neutral gauge boson X originated from a hidden U(1) extension of the standard model as the particle dark matter candidate.

• The vector dark matter interacts with the standard model fermions through heavy fermion mediators.
• The interactions give rise to t-channel annihilation cross section in the XX to ff process, which dominates the thermal relic abundance during thermal freeze-out and produces measurable gamma-ray flux in the galactic halo.
• For a light vector dark matter, if it predominantly couples to the third generation fermions, this model could explain the excess of gamma rays from the galactic center.