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 ϕ, transforming as an N-plet (N > 3) under SU(2)L. Since some of the component fields of ϕ carry large electric charges, loop induced dark matter annihilation to γγ and γZ 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 ϕ 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 ϕ lead to significantly modified h → γγ and h → γZ branching ratios.