Cosmic-Ray Bounds on Lepton-Flavor-Violating Dark-Matter Decays

Cukierman, Ariel J.

Publication

Cosmic-Ray Bounds on Lepton-Flavor-Violating Dark-Matter Decays

Cukierman, Ariel J.

Abstract

We consider possible leptonic three-body decays of spin-1/2 charge-asymmetric dark matter. Assuming a general Dirac structure for the four-fermion contact interactions of interest, we study the cosmic-ray electron and positron spectra and show that good fits to the current data can be obtained for both charged-lepton-flavor-conserving and flavor-violating decay channels. We find that different choices for the Dirac structure of the underlying decay operator can be significantly compensated by different choices for the dark-matter mass and lifetime. The decay modes we consider provide differing predictions for the cosmic-ray positron fraction at energies higher than those currently probed at the PAMELA experiment; these predictions might be tested at cosmic-ray detectors like AMS-02. Additionally, we consider the constraints imposed on these decays by neutrino and gamma-ray observatories.