School of Physics Professor Ignacio Taboada provided brief commentary on KM3NeT, a new underwater neutrino experiment that has detected what appears to be the highest-energy cosmic neutrino observed to date.

“This is clearly an interesting event. It is also very unusual,” said Taboada, spokesperson for the IceCube experiment in Antarctica. IceCube, which has a similar detector-array design as KM3NeT but is encased in ice rather than water, has detected neutrinos with energies as high as 10 PeV, but nothing in 100 PeV range. “IceCube has worked for 14 years, so it’s weird that we don’t see the same thing,” Taboada said. Taboada is not involved in the KM3Net experiment. 

The KM3NeT team is aware of this weirdness. They compared the KM3-230213A event to upper limits on the neutrino flux given by IceCube and the Pierre Auger cosmic-ray experiment in Argentina. Taking those limits as given, they found that there was a 1% chance of detecting a 220-PeV neutrino during KM3NeT’s preliminary (287-day) measurement campaign. 

This also appeared in Scientific American and Smithsonian Magazine.