Ponente
Descripción
The recent detection of a multi-PeV neutrino event by KM3NeT/ARCA opens a new window into the origin of high-energy neutrinos and ultra-high-energy cosmic rays. We revise the possibility of a cosmogenic origin of this neutrino by analysing the constraints induced by cascaded photons onto the isotropic gamma-ray background measured by the Fermi-LAT collaboration.
We consider two scenarios: the first one, at low energies, with a primary proton population saturating the proton content inferred in the data of the Pierre Auger Observatory. The second one consists of a sub-population of protons contaminating the UHECR flux at the highest energies. Remarkably, the cascaded photons constrain the low-energy scenario which cannot explain the KM3-230213A event, if the cosmological evolution of the sources is too strong, because the corresponding gamma-ray spectrum would overshoot the measurements. By contrast, the high-energy scenario is allowed by current cosmic-rays, neutrinos and gamma-rays data and only future measurements of the UHECR composition will further constrain this scenario.
