Facility · Neutrinos
KM3NeT (ARCA and ORCA)
Deep-sea Cherenkov neutrino telescopes
- Status
- Under construction
- Location
- Mediterranean Sea, off Sicily (ARCA) and off Toulon (ORCA)
- Operator
- KM3NeT Collaboration
- Next
- ARCA and ORCA construction continues; new analyses of KM3-230213A
Summary
Two detectors under construction: ARCA (astrophysics, high energies) and ORCA (oscillations, neutrino mass ordering). They take data as they grow; the partly built ARCA has already recorded a record event.
Now as of 4 Nov 2026
The main topic is the event KM3-230213A (13 February 2023, estimated energy ~220 PeV), the most energetic neutrino ever recorded, published in Nature in February 2025. In 2026 the collaboration showed in JCAP that a population of blazars could explain the event without conflicting with gamma-ray and neutrino limits; other papers discuss a possible Galactic origin (KM3NeT/ANTARES, JCAP, PDF). No second ultra-high-energy event has been reported so far.
Results
- 2026Blazar interpretation of KM3-230213A — JCAP (KM3NeT Collaboration)
- 2026Limit on the neutrino–nucleon cross-section from the event — preprint arXiv:2603.28941
- Feb 2025Detection of a ~220 PeV neutrino — Nature — Harvard Physics