Dr. Antonio Marinelli (UNINA & INFN-Napoli)
27 February 2025
11:30, Aula Piazzi
Abstract:
In this presentation we report an exceptional observation made by the KM3NeT telescope on 13th February 2023, when a horizontal track produced by a 120 petaelectronvolts (PeV) muon was recorded. The neutrino associated to the observed muon has an estimated energy of 220 (72 PeV – 2.6 EeV) petaelectronvolts (PeV), the most energetic neutrino so far measured. Such events can be produced when ultra-relativistic cosmic-ray protons or nuclei, produced in the extreme astrophysical environment, interact with matter or photons. The cosmic neutrino energy spectrum measured up to now falls steeply with energy, however the flux inferred by this event breaks the TeV-PeV known power laws. This suggests that the neutrino may have originated in a different cosmic environment than the lower-energy neutrinos, or this may be the first detection of a cosmogenic neutrino, resulting from the interactions of ultra-high-energy cosmic rays with background photons in the Universe. Based on this assumption this event can be a signature of the furthest cosmic accelerator so far observed in this energy range. Different astrophysical scenarios made to explain it will be treated in this talk.