Two Beams, One Detector: MicroBooNE’s Definitive Test of Light Sterile Neutrinos

by Jay Hyun Jo (Brookhaven National Laboratory)

Tuesday 16 Dec 2025, 15:30 → 16:30 US/Eastern

Hints of a light sterile neutrino have persisted for decades, motivated by anomalies reported by LSND, MiniBooNE, and gallium source experiments. MicroBooNE was built in part to provide a decisive test of these results using the imaging capabilities of a liquid-argon TPC. In this colloquium, I will present our new oscillation search that, for the first time, combines data from two accelerator neutrino beams—BNB and NuMI—observed in a single detector. Their very different flavor compositions allow us to break a key degeneracy between electron-neutrino appearance and disappearance that has limited previous searches. With this approach, we find no evidence for oscillations driven by a light sterile neutrino and exclude the LSND and MiniBooNE allowed regions at the 95% confidence level. I will discuss how the dual-beam strategy enables this result and what it means for interpreting short-baseline anomalies going forward.

 

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20251216_JHJ_BNLColloquium_uBSterile.pdf