The event, KM3-230213A, is the first evidence that neutrinos of such high energies are produced in the Universe and the most energetic neutrino ever observed.
Neutrinos are the second most abundant particle in the Universe after photons but they have no electric charge, almost no mass and interact so weakly with matterthey remain the most mysterious of elementary particles. Experiments require enormous detectors, in this instance the Astroparticle Research with Cosmics in the Abyss (ARCA) detector 2 miles under the sea 40 miles off the coast of Sicily is a cubic kilometer(!) in size.
This was a single muon which crossed the entire detector, creating signals in over a third of the active sensors. Its trajectory combined with its record energy leads to inference that the muon originated from a cosmic neutrino in the vicinity of the detector.
Supernova explosions and gamma ray bursts are believed to be cosmic accelerators generating streams of cosmic ray particles that may interact with matter or photons around the source, producing neutrinos and photons. Some may also interact with photons of the cosmic microwave background radiation and produce extremely energetic “cosmogenic” neutrinos.
This could be the first detection of a cosmogenic neutrino.
The KM3NeT neutrino telescope and ARCA was built to learn about fundamental neutrino properties, particularly neutrino oscillations. to try and determine the neutrino mass. It uses sea water to 'catch' neutrinos while optical modules detect the Cherenkov light, a blue glow generated during propagation through the water thanks to ultra-relativistic particles produced in neutrino interactions.
According to Aart Heijboer, KM3NeT Physics and Software Manager and researcher at Nikhef National Institute for Subatomic Physics in Nederlands, "This remarkable detection was achieved with only one tenth of the final configuration of the detector, demonstrating the great potential of our experiment for the study of neutrinos and for neutrino astronomy.”
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