Title: Latest Insights from the Deep-Mediterranean Neutrino Telescopes

Speaker: Prof. Antoine Kouchner, Université Paris Cité

Abstract: Neutrinos, elusive messengers of both the infinitely small and the infinitely large, provide invaluable insights into fundamental physics and astrophysical phenomena. Due to their weak interaction with matter and neutral charge, they traverse cosmic distances without deflection, offering a unique probe into the most energetic events in the Universe. Neutrino telescopes, such as the pioneering ANTARES and the next-generation detector KM3NeT, deployed in the Mediterranean Sea, are designed to capture the Cherenkov light induced by neutrino interactions. These detectors enable studies ranging from neutrino oscillations and mass ordering (KM3NeT/ORCA) to the identification of cosmic neutrino sources (KM3NeT/ARCA).

In this talk, we will review the latest advancements in neutrino (astro)physics emerging from the depths of the Mediterranean and explore the synergies between neutrino physics, Earth, and marine sciences. Particular emphasis will be placed on the recent detection by KM3NeT of an ultra-high-energy neutrino event, dubbed KM3-230213A. The detected particle is a muon with an estimated energy of 120(+110−60) PeV. Its extreme energy and near-horizontal trajectory suggest that the parent neutrino originated from a cosmic accelerator or may represent the first detection of a cosmogenic neutrino, produced by ultra-high-energy cosmic rays interacting with background photons in the Universe. This unprecedented observation highlights the immense potential of deep-sea neutrino telescopes for unveiling new astrophysical phenomena.