Hunting super-heavy dark matter with ultra-high energy photons

TL;DR

This paper explores the potential of ultra-high energy photon observations to detect super-heavy dark matter decays, proposing new search strategies and discussing implications for cosmology.

Contribution

It introduces novel methods for using UHE photon data to probe super-heavy dark matter models and connects these searches to broader cosmological parameters.

Findings

Current and future observatories can constrain SHDM models

Decays of SHDM could produce detectable UHE photons

Links between SHDM constraints and cosmological parameters

Abstract

At any epoch, particle physics must be open to completely unexpected discoveries, and that is reason enough to extend the reach of searches for ultra-high energy (UHE) photons. The observation of a population of photons with energies $E \gtrsim 100$ EeV would for example imply the existence of either a completely new physical phenomena, or particle acceleration mechanisms heretofore never seen or imagined. But as we outline in this Letter of Interest, there are also good arguments for super-heavy dark matter (SHDM) in a parameter range such that it could be discovered via its decays to, in particular, UHE photons. Only ultra-high energy cosmic ray observatories have capabilities to detect UHE photons. We first investigate how current and future observations can probe and constrain SHDM models in important directions, and then outline some of the scenarios that motivate such searches. We also discuss connections between constraints on SHDM and on the parameter values of cosmological models.