Top-Down Models and Extremely High Energy Cosmic Rays

TL;DR

This paper presents a numerical code to calculate the extragalactic spectra of leptons, nucleons, and gamma rays from top-down models involving cosmic topological defects and super-heavy long-living particles, exploring their spectral contributions.

Contribution

The authors developed a new numerical tool for modeling the extragalactic spectra from top-down cosmic ray sources, covering multiple scenarios of particle origin.

Findings

The code successfully computes spectra for various top-down scenarios.

Different topological defect models produce distinct spectral signatures.

Long-lived super-heavy particles contribute significantly to high-energy cosmic rays.

Abstract

We developed numerical code for calculation of the extragalactic component of the spectra of leptons, nucleons and $\gamma$-rays resulting from ``top-down'' (non-acceleration) models for the case of uniform and isotropic source distribution. We explored two different classes of ``top-down'' scenarios: the wide earlier investigated class of X particles coming from collapse and/or annihilation of cosmic topological defects (such as cosmic strings, monopoles, etc.) and the models of super-heavy long-living X particles with lifetime of the order or much greater than the current Universe age.