MicroBooNE Experiment Rules Out Existence of Sterile Neutrino

The MicroBooNE experiment, a collaborative effort involving 193 scientists from 40 institutions across six countries, has ruled out the existence of a sterile neutrino with 95% certainty. This conclusion, published in the journal *Nature*, addresses longstanding anomalies in neutrino behavior that have puzzled physicists for decades. The experiment, conducted at the U.S. Department of Energy’s Fermi National Accelerator Laboratory, utilized a unique two-beam configuration to analyze neutrino interactions, significantly reducing uncertainties in the results.

MicroBooNE Finds No Evidence for Sterile NeutrinoMicroBooNE international collaboration rules out existence of sterile neutrinoFermilab’s MicroBooNE rules out existence of an elusive sterile neutrino

Neutrinos are elementary particles that rarely interact with matter, often referred to as "ghost particles." The Standard Model of particle physics recognizes three types of neutrinos: electron, muon, and tau. However, previous experiments, including the Liquid Scintillator Neutrino Detector (LSND) in 1995 and Fermilab’s MiniBooNE experiment in 2002, observed anomalies suggesting the existence of a fourth type, the sterile neutrino. This hypothetical particle was proposed to explain unexpected oscillations between muon and electron neutrinos that could not be accounted for by the three known flavors.

Fermilab’s MicroBooNE rules out existence of an elusive sterile neutrinoMicroBooNE Finds No Evidence for Sterile NeutrinoMicroBooNE international collaboration rules out existence of sterile neutrino

MicroBooNE operated from 2015 to 2021, employing a 170-ton liquid argon time projection chamber to detect neutrino interactions. By utilizing both the Booster Neutrino Beam (BNB) and the Neutrinos at the Main Injector (NuMI), the experiment was able to capture detailed 3D images of neutrino events. This dual-beam approach allowed researchers to exclude nearly the entire favored region where a sterile neutrino might exist, thus providing a clearer understanding of neutrino behavior.

Fermilab’s MicroBooNE rules out existence of an elusive sterile neutrinoMicroBooNE Finds No Evidence for Sterile NeutrinoMicroBooNE international collaboration rules out existence of sterile neutrino

The ruling out of the sterile neutrino hypothesis has significant implications for the field of particle physics. As Stephen Pate-Morales, a collaborator on the MicroBooNE experiment, noted, “A pretty astonishing number of hypotheses associated with the sterile neutrino have basically been eliminated.” With this explanation no longer viable, physicists are now tasked with exploring alternative theories to account for the observed anomalies, such as more complex neutrino models or potential connections to dark matter.

MicroBooNE international collaboration rules out existence of sterile neutrinoFermilab’s MicroBooNE rules out existence of an elusive sterile neutrinoMicroBooNE Finds No Evidence for Sterile Neutrino

Despite the clarity provided by MicroBooNE's findings, the underlying anomalies remain unexplained. Critics argue that ruling out the sterile neutrino does not resolve the fundamental issues within the Standard Model. As Nitish Nayak, a postdoctoral research associate at Brookhaven National Laboratory, stated, “MicroBooNE is finally closing the chapter on one of the strongest explanations over the past few decades for those anomalies.” The ongoing analysis of the remaining data from MicroBooNE, along with future experiments like the Short-Baseline Neutrino Program and the Deep Underground Neutrino Experiment (DUNE), will be crucial in the quest for new physics.

MicroBooNE international collaboration rules out existence of sterile neutrinoFermilab’s MicroBooNE rules out existence of an elusive sterile neutrinoMicroBooNE Finds No Evidence for Sterile Neutrino

• “What MicroBooNE was able to show is that these sterile neutrinos don’t exist,” — Stephen Pate-Morales, NMSU Physics Professor Emeritus

MicroBooNE international collaboration rules out existence of sterile neutrino

• “MicroBooNE is finally closing the chapter on one of the strongest explanations over the past few decades for those anomalies.” — Nitish Nayak, Postdoctoral Research Associate, Brookhaven National Laboratory

Fermilab’s MicroBooNE rules out existence of an elusive sterile neutrino

• “They saw flavor change on a length scale that is just not consistent with there only being three neutrinos,” — Justin Evans, Professor, University of Manchester

MicroBooNE Finds No Evidence for Sterile Neutrino

The MicroBooNE experiment marks a significant milestone in neutrino research, paving the way for future investigations into the fundamental nature of these elusive particles and the mysteries of the universe.

MicroBooNE international collaboration rules out existence of sterile neutrino