Speaker
Description
The KM3NeT infrastructure comprises two detectors currently under construction in the Mediterranean Sea: KM3NeT/ARCA, designed for the study of high-energy cosmic neutrinos, and KM3NeT/ORCA, optimized for neutrino oscillation studies. The two detectors are already actively taking data, providing competitive results. On February 13th, 2023, the KM3NeT/ARCA neutrino telescope detected the most energetic neutrino ever observed. The event produced a muon with an energy of about 120 PeV at the detector, likely originating from the interaction of an even higher-energy neutrino. In this contribution, we present the details of the detection and we report the subsequent studies performed by the KM3NeT collaboration to investigate its possible origin.
The investigations address the possibility of a Galactic contribution, explore a cosmogenic scenario associated with ultra-high-energy cosmic-ray interactions, and examine potential correlations with known astrophysical sources. The event is also interpreted in the framework of compatibility with the diffuse flux measured by IceCube, allowing constraints on the contribution from diffuse source populations such as GRBs and AGN. Its reconstructed direction and extreme energy enable the derivation of competitive bounds on possible Lorentz Invariance Violation, while the event topology provides sensitivity to the nature of the parent neutrino. Altogether, KM3-230213A stands as a reference event for the experiment, marking a milestone that has prompted the development of dedicated ultra-high-energy analyses in the collaboration.