Highest-energy neutrino detected to date
Discovery of an ultra-high-energy cosmic neutrino with KM3NeT neutrino telescope. Scientific team from FMFI UK in Bratislava is part of KM3NeT collaboration.
On Wednesday, February 12, 2025, by means of a publication in Nature journal, scientists operating and developing KM3NeT neutrino telescope in Mediterranean Sea announced observation of the most energetic cosmic neutrino with energy of 220 PeV (1 PeV = 1015 eV), surpassing the previous record of the IceCube neutrino telescope at the South Pole, which detected a neutrino with an energy of 6 PeV. (youtube: https://www.youtube.com/watch?v=2jgyZlBpkl8&t=1811s ). This event, practically near-horizontal muon traversing three-dimensional network of optical modules (photosensors) of the telescope, was registered on February 13, 2023 by the ARCA detector that is located offshore Sicily at a depth of about 3450 m. At that time, the detector which aims on recording the Cherenkov radiation consisted of 21 operational detection units. Each detection unit houses 18 optical modules approximately equally spaced on strings that are about 700 m long. Based on high energy of this muon (approximately 120 PeV) and its trajectory, team concluded that the particle cannot be produced by collisions of cosmic rays in Earth’s atmosphere, but it is produced by a cosmic neutrino. This is indeed groundbreaking discovery in the field of astronomy, astrophysics and human knowledge. (https://doi.org/10.1038/s41586-024-08543-1). Scientific team from FMFI UK in Bratislava – prof. Fedor Šimkovic, Dr. Rastislav Dvornický, Eliška Eckerová, and Zuzana Bardačová (PhD students) - is part of KM3NeT collaboration.
Neutrino telescopes observe instead of light high energy neutrinos that are messengers from deep Universe. These particles can travel vast distances in space without distortion of their direction. Registration of galactic and extra-galactic neutrinos can reveal the origin of ultra-high-energy cosmic rays, gamma ray bursts, shed light on objects like active galactic nuclei and unique processes in Universe – supernova explosions, collisions of stars, galaxies, black holes, etc. The aims of neutrino astrophysics are being gradually fulfilled with operation of neutrino telescopes like Baikal-GVD (0.6 km3 volume), IceCube (1 km3 volume), KM3NeT (0.2 km3 volume), and P-ONE. These experiments present the first map of high-energy neutrino sources which is unique and address the need of further research in the field of neutrino astronomy. The detection volumes of these telescopes are still growing. There are Chinese projects HUNT and TRIDENT in preparation with planned volume of about 20km3.