Ultra high energy cosmic rays from super-heavy dark matter in the context of large exposure observatories

TL;DR

This paper explores the potential of future large exposure cosmic ray observatories to detect ultra high energy cosmic rays originating from the decay of super-heavy dark matter particles in galactic halos, considering both galactic and extragalactic contributions.

Contribution

It investigates the detectability of super-heavy dark matter decay signatures in ultra high energy cosmic rays with upcoming observatories, expanding on current models and observational capabilities.

Findings

Potential to identify dark matter decay signals in future data

Galactic halo contributions dominate the expected flux

Extragalactic halo effects are also significant

Abstract

The origin of the ultra high energy cosmic rays (UHECRs, $E>10^{18}$ eV) is still uncertain. However, great progress has been achieved due to the data taken by The Pierre Auger and Telescope Array observatories. The UHECR flux presents two main features, a hardening of the spectrum known as the ankle and a suppression at higher energies. The experimental data suggest that above the ankle the UHECRs flux is dominated by an extragalactic component of astrophysical origin. However, a minority component of exotic origin that dominates the flux beyond the suppression is still compatible with current data. Therefore, there exist the possibility that part of the UHECR flux originates from the decay of super-heavy dark matter particles clustered in the halos of the galaxies. In these scenarios the main contribution comes from the halo of our galaxy. In this article the possibility of identifying these scenarios in the context of the future very large exposure cosmic rays observatories is studied. It is worth mentioning that the contribution of the extragalactic halos located in the nearby universe is also included in these studies.