On the Cosmic-Ray Spectra of Three-Body Lepton-Flavor-Violating Dark Matter Decays

TL;DR

This paper investigates how three-body leptonic decays of spin-1/2 dark matter can explain cosmic-ray electron and positron data, with predictions that could be tested by future cosmic-ray experiments.

Contribution

It introduces a comprehensive analysis of leptonic three-body dark matter decays with general Dirac structures, exploring their effects on cosmic-ray spectra and potential experimental signatures.

Findings

Good fits to current cosmic-ray data are achievable with various decay modes.

Different Dirac structures can be offset by adjustments in dark matter mass and lifetime.

Predictions for high-energy positron fractions could be tested by AMS-02.

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.