Statistical significance of the sterileneutrino hypothesis in the context of reactor and gallium data
Abstract
We evaluate the statistical significance of the 3+1 sterileneutrino hypothesis using ν_{e} and 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 sterileneutrino oscillations from reactor data. On the other hand, gallium data (dominated by the BEST result) show more than 5 σ of evidence supporting the sterileneutrino 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 crosssection uncertainties on the results.
 Publication:

Journal of High Energy Physics
 Pub Date:
 February 2022
 DOI:
 10.1007/JHEP02(2022)055
 arXiv:
 arXiv:2111.12530
 Bibcode:
 2022JHEP...02..055B
 Keywords:

 Beyond Standard Model;
 Neutrino Physics;
 High Energy Physics  Phenomenology;
 High Energy Physics  Experiment;
 Nuclear Experiment
 EPrint:
 37 pages plus references, 9 figures. v2: Minor changes, references added. Matches version accepted for publication in JHEP