Overview
- Germany’s KATRIN tritium beta-decay spectrometer compared over 36 million electron events with theory and saw no sterile-neutrino signatures in the spectrum.
- Fermilab’s MicroBooNE used two accelerator neutrino beams and a liquid-argon time projection chamber to test muon-to-electron oscillations, excluding a single light sterile neutrino at about 95% confidence.
- Both collaborations published their results in Nature in December 2025.
- The combined constraints rule out sterile neutrinos as the cause of some, though not all, short-baseline anomalies reported by LSND and MiniBooNE.
- Scientists say the findings shift attention to alternative models and will inform upcoming efforts, including the Deep Underground Neutrino Experiment (DUNE).