A decades-long puzzle in neutrino physics has finally taken a significant step forward, thanks to an international collaboration of scientists working on the MicroBooNE experiment. The team has discovered no evidence for a fourth type of neutrino, ruling out one possible explanation for anomalies observed in previous experiments. This finding confirms that there are only three types of neutrinos in the Standard Model, as predicted.
The discovery was made using data collected by MicroBooNE from 2015 to 2021 and is based on comparisons with observations from the Liquid Scintillator Neutrino Detector (LSND) at Los Alamos National Laboratory. While the team has ruled out a single sterile neutrino explanation, the mystery remains unsolved.
The Standard Model of particle physics explains many phenomena in the natural world but is incomplete. Physicists are now searching for new physics to shed light on the biggest mysteries in the universe, including dark matter and gravity.
Neutrinos, ghostly particles that oscillate between three flavors, have been a subject of study for decades. Recent observations suggested that muon neutrinos were oscillating into electron neutrinos over shorter distances than expected. The most popular explanation for this anomaly is the existence of a sterile neutrino. However, MicroBooNE’s findings make it highly unlikely that such a particle exists.
The discovery highlights the importance of experimental searches in physics and demonstrates the power of combining data from multiple detectors to rule out certain explanations. Researchers are now shifting their focus to more complex models, such as the Short-Baseline Neutrino Program, which uses a multi-detector approach to investigate alternative explanations for the anomalies observed by MiniBooNE and LSND.
The MicroBooNE collaboration consists of 193 scientists from 40 institutions across six countries. This achievement demonstrates the strength of international cooperation in particle physics research.
Source: https://news.fnal.gov/2025/12/microboone-finds-no-evidence-for-a-sterile-neutrino