KM3NeT detects the highest energy neutrino ever observed
NWO Institutes Nikhef and NIOZ and NWO-I involved in international KM3NeT collaboration
The KM3NeT Collaboration announced the detection from the abyss of the Mediterranean Sea of a cosmic neutrino (an electrically uncharged subatomic elementary particle) with a record-breaking energy of about 220 PeV yesterday. The ARCA detector of the kilometre cubic neutrino telescope (KM3NeT) in the deep sea, detected the extraordinary event on 13 February 2023. This event is the most energetic neutrino ever observed and provides the first evidence that neutrinos of such high energies are produced in the Universe.
After long and meticulous work to analyse and interpret the experimental data, on 12 February 2025, the international scientific collaboration of KM3NeT reports the details of this amazing discovery in an article published in Nature.
The detected event was identified as a single muon which crossed the entire detector, inducing signals in more than one third of the active sensors. The inclination of its trajectory combined with its enormous energy provides compelling evidence that the muon originated from a cosmic neutrino interacting in the vicinity of the detector.
"KM3NeT has begun to probe a range of energy and sensitivity where detected neutrinos may originate from extreme astrophysical phenomena. This first ever detection of a neutrino of hundreds of PeV opens a new chapter in neutrino astronomy and a new observational window on the Universe", comments Paschal Coyle, KM3NeTSpokesperson at the time of the detection, and researcher at CNRS Centre National de la Recherche Scientifique – Centre de Physique des Particules de Marseille, France.
Detecting neutrinos with KM3NeT
Although neutrinos are the second most abundant particle in the Universe after photons, their weak interaction with matter makes them very hard to detect and requires enormous detectors. The KM3NeT neutrino telescope, currently under construction, is a giant deep-sea infrastructure distributed across two detectors ARCA and ORCA. In its final configuration, KM3NeT will occupy a volume of more than one cubic kilometre. KM3NeT uses sea water as the interaction medium for neutrinos. Its high-tech optical modules detect the Cherenkov light, a bluish glow that is generated during the propagation through the water of the ultra-relativistic particles produced in neutrino interactions.
Dutch researchers and engineers play an important role
Dutch scientists and engineers are closely involved in this extraordinary discovery. From the Netherlands, Nikhef, NWO-I, the University of Amsterdam, Leiden University, NIOZ and TNO are members of the KM3NeT collaboration. They hold various leadership positions within the collaboration, collaborating on the design, construction and deployment of the detector, system engineering, software development and the final analysis of the data.
"What a very wonderful observation. This is promising for the future of this research field. I look forward to the next few years of expanding KM3NeT. That our researchers and technicians are involved in so many parts of this undersea telescope shows the strength of the Nikhef partnership in which theory, experiment and instrumentation come together," says Jorgen D'Hondt, Director of Nikhef.
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