Experimental Ultra--High-Energy Cosmic Ray Physics

TL;DR

This paper reviews the current experimental understanding of ultra-high-energy cosmic rays, discussing their energy spectrum, origins, and the challenges in explaining their acceleration and travel across cosmic distances.

Contribution

It provides a comprehensive overview of recent experimental results and summarizes the status of ultra-high-energy cosmic ray research.

Findings

Confirmation of cosmic rays with energies >10^20 eV

Recent data on energy spectrum and arrival directions

Discussion of open questions in cosmic ray acceleration

Abstract

One of the most striking astrophysical phenomena today is the existence of cosmic ray particles with energies in excess of 10^20 eV. While their presence has been confirmed by a number of experiments, it is not clear where and how these particles are accelerated to these energies and how they travel astronomical distances without substantial energy loss. We are entering an exciting new era in cosmic ray physics, with instruments now producing data of unprecedented quality and quantity to tackle the many open questions. This paper reviews the current experimental status of cosmic ray physics and summarizes recent results on the energy spectrum and arrival directions of ultra-high-energy cosmic rays.