Statistical Significance of Reactor Antineutrino Active-Sterile Oscillations

Abstract

We performed Monte Carlo calculations of the statistical distribution of the $\chi^2$ test statistic used in the analysis of the data of the NEOS, DANSS, Bugey-3, and PROSPECT short-baseline reactor experiments. We show that the statistical significance of the NEOS and DANSS indications in favor of active-sterile neutrino oscillations is smaller than that obtained with the usual method based on the $\chi^2$ distribution. In the combined analysis of the data of the four experiments we find that the statistical significance of active-sterile neutrino oscillations is reduced from $2.4\sigma$ to $1.8\sigma$.