The building that houses the IceCube servers. (credit: USAP.gov)

Tantalizing hints have regularly turned up to indicate the existence of a sterile neutrino—a theoretical fourth type of neutrino separate from the three predicted by the Standard Model. Researchers have now searched for it using the IceCube Neutrino Observatory, a powerful neutrino detector in Antarctica that is able to spot neutrinos of cosmic origin. Could this particle finally be found, ushering in a thrilling new era of physics?

No. IceCube’s search has turned up nothing, as revealed in results published today. The lack of detection doesn’t necessarily mean sterile neutrinos don’t exist, but it does put the strictest constraints on them yet, narrowing down the range of energies they could have and informing future studies on where to look.

Had sterile neutrinos been found, they would have explained anomalies in old research, revealed new physics beyond the Standard Model, and potentially provided clues for mysteries such as the nature of dark matter and the imbalance between matter and anti-matter in the Universe. “If you throw in a fourth neutrino, it changes everything,” said Francis Halzen, principle investigator for IceCube and one of the paper’s authors.