Simplified Dark Matter Models for the Galactic Center Gamma-Ray Excess
  Motivated by the gamma-ray excess observed from the region surrounding the
Galactic Center, we explore particle dark matter models that could potentially
account for the spectrum and normalization of this signal. Taking a
model-independent approach, we consider an exhaustive list of tree-level
diagrams for dark matter annihilation, and determine which could account for
the observed gamma-ray emission while simultaneously predicting a thermal relic
abundance equal to the measured cosmological dark matter density. We identify a
wide variety of models that can meet these criteria without conflicting with
existing constraints from direct detection experiments or the Large Hadron
Collider (LHC). The prospects for detection in near future dark matter
experiments and/or the upcoming 14 TeV LHC appear quite promising.
