Monochromatic Gamma Rays from Dark Matter Annihilation to Leptons

24 Aug 2015, 15:10
Bay ()


Particle Cosmology Theory and Experiment Particle Cosmology


Adam Coogan (UC Santa Cruz)


We investigate the relation between the annihilation of dark matter (DM) particles into lepton pairs and into 2-body final states including one or two photons. We parametrize the DM interactions with leptons in terms of contact interactions, and calculate the loop-level annihilation into monochromatic gamma rays, specifically computing the ratio of the DM annihilation cross sections into two gamma rays versus lepton pairs. While the loop-level processes are generically suppressed in comparison with the tree-level annihilation into leptons, we find that some choices for the mediator spin and coupling structure lead to large branching fractions into gamma-ray lines. We also explore the possibility of mediators which are charged under a dark symmetry and find that, for these loop-level processes, an effective field theory description is accurate for DM masses up to about half the mediator mass.

Primary author

Adam Coogan (UC Santa Cruz)


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