We present simplified models for the galactic center $\gamma$-ray excess where Dirac dark matter annihilates into pairs or triplets of on-shell bosonic mediators to the standard model. These annihilation modes allow the dark matter mass to be heavier than those of conventional effective theories for the $\gamma$-ray excess. Because the annihilation rate is set by the dark matter–mediator coupling, the standard model coupling can be made parametrically small to “hide” the dark sector by suppressing direct detection and collider signals. We explore the viability of these models as a thermal relic and on the role of the mediators for controlling the $\gamma$-ray spectral shape. We comment on ultraviolet completions for these simplified models and novel options for standard model final states.

• Received 15 May 2014

DOI:https://doi.org/10.1103/PhysRevD.90.035004