# Superheavy Gravitinos and Ultra-High Energy Cosmic Rays

## TL;DR

This paper proposes that superheavy gravitinos, as dark matter candidates, could explain ultra-high energy cosmic rays through annihilation in neutron star skins, linking particle physics and astrophysical observations.

## Contribution

It introduces a novel mechanism where superheavy gravitino annihilation in neutron stars accounts for UHECRs, suggesting a connection between dark matter properties and cosmic ray phenomena.

## Key findings

- UHECR events can originate from neutron stars within 50 Mpc.
- Superheavy gravitinos are stable and interact strongly, enabling this mechanism.
- Heavy ions in cosmic rays may be explained by neutron star surface composition.

## Abstract

We argue that the superheavy gravitinos that we had previously proposed as candidates for Dark Matter can offer a possible explanation for the ultra-high energy cosmic ray (UHECR) events observed at the Pierre Auger Observatory, via gravitino anti-gravitino annihilation in the `skin' of neutron stars. The large mass and strong interactions of these particles, together with their stability against decays into standard matter are essential for the proposed explanation to work. In particular, it ensues that UHECR events can be understood to originate from neutron stars inside a GKZ horizon of $\sim$ 50 Mpc. The composition of neutron stars near their surface could play a crucial role in explaining the presence of heavy ions in these events. If confirmed, this new mechanism can be taken as evidence for the fundamental ansatz towards unification on which it is based.