Sterile neutrino fits to short baseline data

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 Δm[subscript 41][superscript 2] = 1.75 eV[superscript 2] with a Δχ[subscript null-min][superscript 2] (dof) of 52.34 (3). The 3+2 fit has a Δχ[subscript null-min][superscript 2] (dof) of 56.99 (7). For the first time, we show Bayesian credible intervals for a 3+1 model. These are found to be in agreement with frequentist intervals. The results of these new fits favor a higher Δm2 value than previous studies, which may have an impact on future sterile neutrino searches such as the Fermilab SBN program.