Hidden Higgs Portal Vector Dark Matter for the Galactic Center Gamma-Ray Excess from the Two-Step Cascade Annihilation, and Muon g-2

Understand

We have built a lepton-specific next-to-minimal two-Higgs-doublet-portal vector dark matter model.

• The vector dark matter in the hidden sector does not directly couple to the visible sector, but instead annihilates into the hidden Higgs bosons which decay through a small coupling into the CP-odd Higgs bosons.
• In this model, the Galactic center gamma-ray excess is mainly due to the 2-step cascade annihilation with $\tau$'s in the final state.
• The obtained mass of the CP-odd Higgs $A$ in the Galactic center excess fit can explain the muon $g-2$ anomaly at the 2$\sigma$ level without violating the stringent constraints from the lepton universality and $\tau$ decays.