Current Understanding of the Highest-Energy Particles in Nature (Antonio Condorelli, APC)
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amphi Charpak
In the era of multi-messenger astronomy, ultra-high-energy cosmic rays (UHECRs) provide a unique probe into the nature of astrophysical sources and particle interactions at energies far beyond the reach of terrestrial accelerators. This contribution will present selected recent results on the energy spectrum, nuclear mass composition, and anisotropies of UHECRs, highlighting how these observations constrain astrophysical scenarios involving both steady and transient sources. Additionally, the study of secondary emissions, including cosmogenic neutrinos produced during UHECR propagation, provides crucial complementary insights. In this context, we will discuss the recent ultra-high-energy event observed by KM3NeT, and its implications for cosmic-ray origin within the multi-messenger framework.