Nuclear Physics Meets the Sources of the Ultra-High Energy Cosmic Rays

TL;DR

This paper investigates how nuclear data uncertainties influence the modeling of ultra-high energy cosmic rays, emphasizing the importance of accurate nuclear physics in understanding cosmic ray sources and propagation.

Contribution

It analyzes the impact of nuclear model uncertainties on cosmic ray composition and propagation, especially in non-thermal radiation environments like gamma-ray bursts.

Findings

Nuclear model uncertainties are larger in non-thermal environments.

Nuclear data significantly affect cosmic ray cascade simulations.

An isotope chart identifies key nuclear interactions needed for modeling.

Abstract

The determination of the injection composition of cosmic ray nuclei within astrophysical sources requires sufficiently accurate descriptions of the source physics and the propagation - apart from controlling astrophysical uncertainties. We therefore study the implications of nuclear data and models for cosmic ray astrophysics, which involves the photo-disintegration of nuclei up to iron in astrophysical environments. We demonstrate that the impact of nuclear model uncertainties is potentially larger in environments with non-thermal radiation fields than in the cosmic microwave background. We also study the impact of nuclear models on the nuclear cascade in a gamma-ray burst radiation field, simulated at a level of complexity comparable to the most precise cosmic ray propagation code. We conclude with an isotope chart describing which information is in principle necessary to describe nuclear interactions in cosmic ray sources and propagation.