From gamma ray line signals of dark matter to the LHC
  We explore the relationship between astrophysical gamma-ray signals and LHC
signatures for a class of phenomenologically successful secluded dark matter
models, motivated by recent evidence for a ~130 GeV gamma-ray line. We consider
in detail scenarios in which interactions between the dark sector and the
standard model are mediated by a vev-less scalar field \phi, transforming as an
N-plet (N > 3) under SU(2)_L. Since some of the component fields of \phi carry
large electric charges, loop induced dark matter annihilation to \gamma \gamma
and \gamma Z can be enhanced without the need for non-perturbatively large
couplings, and without overproduction of continuum gamma-rays from other final
states. We discuss prospects for other experimental tests, including dark
matter-nucleon scattering and production of \phi at the LHC, where future
searches for anomalous charged tracks may be sensitive. The first LHC hints
could come from the Higgs sector, where loop corrections involving \phi lead to
significantly modified h to \gamma \gamma and h to \gamma Z branching ratios.
