The Snowmass Ultra-High-Energy Cosmic Ray White Paper

This talk will give an overview of the key findings and recommendations of the White Paper, Ultra-High-Energy Cosmic Rays: The Intersection of the Cosmic and Energy Frontiers, prepared for the Snowmass process. The paper starts with an overview of the recent progress and open questions on ultra-high-energy cosmic rays (UHECRs), with energies greater than 100 PeV, through the lenses of particle physics and astrophysics. It then moves to frame the future potential of the field over the next 10 years, highlighting promising analysis avenues for approaching the community's long-standing goals. Finally, it lays out a 20-year road-map for UHECR science, providing key recommendations on what to consider when funding and building the next generation of UHECR observatories.