The contribution to the antimatter flux from individual dark matter substructures

TL;DR

This paper analyzes how individual dark matter substructures contribute to local antimatter fluxes, emphasizing the importance of source motion and providing analytic solutions for positron and antiproton propagation.

Contribution

It derives analytic solutions for time-dependent antimatter propagation from dark matter sources, highlighting limitations in extracting particle physics parameters from data.

Findings

Static approximation is valid only for high-energy, nearby sources.

Unique determination of dark matter particle properties from antimatter fluxes is not possible.

FERMI-LAT can distinguish gamma-ray signals from dark matter models.

Abstract

The local antimatter fluxes induced by an individual dark matter (DM) substructure can be significantly dependent on the proper motion of the source. We derive analytic solutions to the propagation equation for time-dependent positron and antiproton primary sources, finding that the static limit is a fair approximation only for very high energy particles and nearby sources. We discuss weakly interacting massive particle (WIMP) models fitting the PAMELA positron excess and the FERMI all-electron data. We show that, for a single non-static DM point-source, one cannot extract from the data, in a unique way, model independent particle physics observables, such as the WIMP mass, the pair annihilation cross section, and the annihilation yield. The gamma-ray emission associated to WIMP models inducing a significant local flux of positrons or antiprotons is found to be compatible with EGRET measurements, but it can be definitely singled out with the FERMI-LAT telescope.