Neutralino dark matter and the Fermi gamma-ray lines
  Motivated by recent claims of lines in the Fermi gamma-ray spectrum, we
critically examine means of enhancing neutralino annihilation into neutral
gauge bosons. The signal can be boosted while remaining consistent with
continuum photon constraints if a new singlet-like pseudoscalar is present. We
consider singlet extensions of the MSSM, focusing on the NMSSM, where a
`well-tempered' neutralino can explain the lines while remaining consistent
with current constraints. We adopt a complementary numerical and analytic
approach throughout in order to gain intuition for the underlying physics. The
scenario requires a rich spectrum of light neutralinos and charginos leading to
characteristic phenomenological signatures at the LHC whose properties we
explore. Future direct detection prospects are excellent, with sizeable
spin-dependent and spin-independent cross-sections.
