A Model Independent Method to Study Dark Matter induced Leptons and Gamma rays

TL;DR

This paper introduces a model-independent method to analyze dark matter induced leptons and gamma rays using recent data, providing constraints on decaying dark matter scenarios without relying on specific particle physics models.

Contribution

It presents a novel approach to determine dark matter induced electron-positron spectra and gamma rays directly from experimental data, independent of specific dark matter models.

Findings

Gamma ray flux predictions are often in tension with Fermi-LAT limits.

Results are robust against variations in cosmic ray propagation and dark matter density profiles.

Constraints suggest additional processes may contribute to gamma ray production besides inverse Compton scattering.

Abstract

By using recent data, we directly determine the dark matter (DM) induced $e^\pm$ spectrum at the source from experimental measurements at the earth, without reference to specific particle physics models. The DM induced gamma rays emitted via inverse Compton scattering are then obtained in a model independent way. However the results depend on the choice of the astrophysical $e^\pm$ background, which is not reliably known. Nevertheless, we calculate, as an illustration, the fluxes of gamma rays from the Fornax cluster in the decaying DM scenario with various astrophysical $e^\pm$ backgrounds. Without any assumptions on details of the DM model, the predictions turn out to be either in disagreement with or only marginally below the upper limits measured recently by the Fermi-LAT Collaboration. In addition, these DM induced ICS gamma rays in the GeV range are shown to be almost independent of choices of cosmic ray propagation model and of DM density profile, when a given astrophysical $e^\pm$ background is assumed. This provides a strong constraint on decaying DM scenario as the gamma rays may be produced in other processes besides inverse Compton scattering, such as the bremsstrahlung and neutral pion decays.