Speaker: Ines Valino Rielo, University of Santiago de Compostela
Abstract: A century after the discovery of cosmic rays, the nature and origin of the highest energy particles in the Universe, the Ultra-High Energy Cosmic Rays (UHECR), remain enigmatic. Thanks to experiments dedicated to probing the extreme end of the energy spectrum, exciting progress is being made in solving these puzzles.The Pierre Auger Observatory is currently the World`s largest detector for UHECR. The goal is to measure the cosmic ray energy spectrum, arrival directions, and the properties of the extensive air showers induced by the UHECRs in the atmosphere with the objective of unveiling cosmic ray elemental composition, origins and propagation effects. The observatory has now collected more data than all previous experiments combined, and employs multiple detection (hybrid) detection techniques allowing for a large exposure and excellent control of systematic uncertainties. The original design, optimized for the energy range from 1018 eV to the end of the spectrum, has recently been enhanced to cover energies down to almost 1017 eV, allowing us to view additional interesting features of the spectrum. I will give an overview of the latest results with a focus on the current status of the search for ultra-high energy neutrinos and photons and the promising prospect to use cosmic rays to study hadronic interactions at energies beyond the reach of the LHC.