Sterile Neutrino Oscillations: The Global Picture

TL;DR

This paper reviews global neutrino oscillation data to investigate the existence of sterile neutrinos at the eV scale, highlighting tensions between different experimental hints and constraints across various neutrino experiments.

Contribution

It provides a comprehensive analysis of sterile neutrino schemes, comparing their compatibility with global data and identifying the most plausible models.

Findings

The 1+3+1 scheme shows the best compatibility with data.

Significant tension exists between appearance and disappearance experiment results.

Sterile neutrino explanations face challenges due to conflicting experimental hints.

Abstract

Neutrino oscillations involving eV-scale neutrino mass states are investigated in the context of global neutrino oscillation data including short and long-baseline accelerator, reactor, and radioactive source experiments, as well as atmospheric and solar neutrinos. We consider sterile neutrino mass schemes involving one or two mass-squared differences at the eV^2 scale denoted by 3+1, 3+2, and 1+3+1. We discuss the hints for eV-scale neutrinos from nu_e disappearance (reactor and Gallium anomalies) and nu_mu->nu_e appearance (LSND and MiniBooNE) searches, and we present constraints on sterile neutrino mixing from nu_mu and neutral-current disappearance data. An explanation of all hints in terms of oscillations suffers from severe tension between appearance and disappearance data. The best compatibility is obtained in the 1+3+1 scheme with a p-value of 0.2% and exceedingly worse compatibilities in the 3+1 and 3+2 schemes.