Speaker
Description
KM3NeT has recorded the transit of the highest-energy neutrino ever observed (KM3-230213A) whose provenience remains at the current time unknown. No astrophysical emitters were identified with a conclusive space correlation to the event, while cosmogenic interpretations require parameters ranges stretched to debated regions of the model. Alternatively to an astrophysical acceleration process, KM3-230213A could owe its energy to the large mass of a progenitor. We have investigated a scenario where KM3-230213A is originated in the decay of a heavy dark matter particle, scanning dark matter mass and lifetime to test which values are best compatible with the KM3NeT observation. The reconstructed neutrino energy was recomputed assuming dark-matter energy distributions instead of an $E^{−2}$ astrophysical spectrum. Results are placed in context with $\gamma$-ray limits from wide-field, non-pointing telescopes (such as LHAASO), and the non-observations reported by neutrino telescopes (IceCube), and cosmic-ray arrays (the Pierre Auger Observatory, TA, CASA-MIA and KASCADE). Restricted portions of the dark matter mass/lifetime parameter space remain compatible with both these limits and the KM3NeT observation, leaving the dark matter decay hypothesis viable. As the coordinates of KM3-230213A are almost diametrically opposed to the centre of the Milky Way, the specific attribution of this event to Galactic or extragalactic dark matter is, however, inconclusive.