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A bstract We evaluate the statistical significance of the 3+1 sterile-neutrino hypothesis using ν e and $$ \overline{\nu} $$ ν ¯ e disappearance data from reactor, solar and gallium radioactive source experiments. Concerning the latter, we investigate the implications of the recent BEST results. For reactor data we focus on relative measurements independent of flux predictions. For the problem at hand, the usual χ 2 -approximation to hypothesis testing based on Wilks’ theorem has been shown in the literature to be inaccurate. We therefore present results based on Monte Carlo simulations, and find that this typically reduces the significance by roughly 1 σ with respect to the naïve expectation. We find no significant indication in favor of sterile-neutrino oscillations from reactor data. On the other hand, gallium data (dominated by the BEST result) show more than 5 σ of evidence supporting the sterile-neutrino hypothesis, favoring oscillation parameters in agreement with constraints from reactor data. This explanation is, however, in significant tension (∼ 3 σ ) with solar neutrino experiments. In order to assess the robustness of the signal for gallium experiments we present a discussion of the impact of cross-section uncertainties on the results.
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This content will become publicly available on December 3, 2026
Search for light sterile neutrinos with two neutrino beams at MicroBooNE
Abstract The existence of three distinct neutrino flavours,νe,νμandντ, is a central tenet of the Standard Model of particle physics1,2. Quantum-mechanical interference can allow a neutrino of one initial flavour to be detected sometime later as a different flavour, a process called neutrino oscillation. Several anomalous observations inconsistent with this three-flavour picture have motivated the hypothesis that an additional neutrino state exists, which does not interact directly with matter, termed as ‘sterile’ neutrino,νs(refs. 3–9). This includes anomalous observations from the Liquid Scintillator Neutrino Detector (LSND)3experiment and Mini-Booster Neutrino Experiment (MiniBooNE)4,5, consistent withνμ → νetransitions at a distance inconsistent with the three-neutrino picture. Here we use data obtained from the MicroBooNE liquid-argon time projection chamber10in two accelerator neutrino beams to exclude the single light sterile neutrino interpretation of the LSND and MiniBooNE anomalies at the 95% confidence level (CL). Moreover, we rule out a notable portion of the parameter space that could explain the gallium anomaly6–8. This is one of the first measurements to use two accelerator neutrino beams to break a degeneracy betweenνeappearance and disappearance, which would otherwise weaken the sensitivity to the sterile neutrino hypothesis. We find no evidence for eitherνμ → νeflavour transitions orνedisappearance that would indicate non-standard flavour oscillations. Our results indicate that previous anomalous observations consistent withνμ → νetransitions cannot be explained by introducing a single sterile neutrino state.
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- Award ID(s):
- 2047665
- PAR ID:
- 10658495
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- Nature
- Date Published:
- Journal Name:
- Nature
- Volume:
- 648
- Issue:
- 8092
- ISSN:
- 0028-0836
- Page Range / eLocation ID:
- 64 to 69
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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