Sterile Neutrino Fits to Short Baseline Data

TL;DR

This paper analyzes short baseline neutrino oscillation data to evaluate models with additional sterile neutrino states, finding a best fit at Delta m^2_41 = 1.75 eV^2 and providing Bayesian credible intervals.

Contribution

It introduces Bayesian credible intervals for 3+1 sterile neutrino models and compares them with frequentist intervals, updating the preferred Delta m^2 value.

Findings

3+1 model best fit at Delta m^2_41 = 1.75 eV^2

Bayesian credible intervals are consistent with frequentist ones

Results suggest higher Delta m^2 than previous studies

Abstract

Neutrino oscillation models involving extra mass eigenstates beyond the standard three (3+N) are fit to global short baseline experimental data. We find that 3+1 has a best fit of Delta m^2_41 = 1.75 eV^2 with a Delta chi^2 [null-min] (dof) of 52.34 (3). The 3+2 fit has a Delta chi^2 [null-min] (dof) of 56.99 (7). Bayesian credible intervals are shown for the first time for a 3+1 model. These are found to be in agreement with frequentist intervals. The results of these new fits favor a higher Delta m^2 value than previous studies, which may have an impact on future sterile neutrino searches such as the Fermilab SBN program.