Gamma Ray Constraints on Flavor Violating Asymmetric Dark Matter

Abstract

We show how cosmic gamma rays can be used to constrain models of asymmetric Dark Matter decaying into lepton pairs by violating flavor. First of all we require the models to explain the anomalies in the charged cosmic rays measured by PAMELA, FERMI and HESS; performing combined fits we determine the allowed values of the Dark Matter mass and lifetime. For these models, we then determine the constraints coming from the measurement of the isotropic gamma-ray background by FERMI for a complete set of lepton flavor violating primary modes and over a range of DM masses from 100 GeV to 10 TeV. We find that the FERMI constraints rule out the flavor violating asymmetric Dark Matter interpretation of the charged cosmic ray anomalies.Comment: 11 pages, 3 figures. v2: constraints derivation slightly modified, conclusions unchanged; some clarifications and some references added; matches version published on JCA