NMSSM Interpretation of the Galactic Center Excess
  We explore models for the GeV Galactic Center Excess (GCE) observed by the
Fermi Telescope, focusing on $\chi \chi \rightarrow f \bar f$ annihilation
processes in the $Z_3$ NMSSM. We begin by examining the requirements for a
simplified model (parametrized by the couplings and masses of dark matter (DM)
and mediator particles) to reproduce the GCE via $\chi \chi \rightarrow f \bar
f$, while simultaneously thermally producing the observed relic abundance. We
apply the results of our simplified model to the $Z_3$ NMSSM for
Singlino/Higgsino(S/H) or Bino/Higgsino(B/H) DM. In the case of S/H DM, we find
that the DM must be be very close to a pseudoscalar resonance to be viable, and
large $\tan\beta$ and positive values of $\mu$ are preferred for evading direct
detection constraints while simultaneously obtaining the observed Higgs mass.
In the case of B/H DM, by contrast, the situation is much less tuned:
annihilation generally occurs off-resonance, and for large $\tan\beta$ direct
detection constraints are easily satisfied by choosing $\mu$ sufficiently large
and negative. The B/H model generally has a light, largely MSSM-like
pseudoscalar with no accompanying charged Higgs, which could be searched for at
the LHC.
