Pragmatic View of Short-Baseline Neutrino Oscillations

TL;DR

This paper analyzes short-baseline neutrino oscillation data across different mixing schemes, concluding that the simplest 3+1 model remains favored, with specific parameter constraints and a need for further experiments to confirm LSND results.

Contribution

It provides a comprehensive global analysis of short-baseline neutrino oscillation data, favoring the 3+1 scheme and constraining its parameters based on current experimental results.

Findings

3+1 scheme remains favored over 3+2 and 3+1+1

Allowed $ riangle m^2_{41}$ range between 0.82 and 2.19 eV$^2$

No oscillation hypothesis disfavored at about 6$\sigma$, reduced to 2$\sigma$ without LSND data

Abstract

We present the results of global analyses of short-baseline neutrino oscillation data in 3+1, 3+2 and 3+1+1 neutrino mixing schemes. We show that the data do not allow us to abandon the simplest 3+1 scheme in favor of the more complex 3+2 and 3+1+1 schemes. We present the allowed region in the 3+1 parameter space, which is located at $\Delta{m}^2_{41}$ between 0.82 and 2.19 $\text{eV}^2$ at $3\sigma$. The case of no oscillations is disfavored by about $6\sigma$, which decreases dramatically to about $2\sigma$ if the LSND data are not considered. Hence, new high-precision experiments are needed to check the LSND signal.