Sterile neutrinos after the first MiniBooNE results

TL;DR

This paper evaluates the impact of recent MiniBooNE results on sterile neutrino models, finding increased tension and disfavoring certain schemes, with limited success in reconciling experimental data.

Contribution

It provides a comprehensive global fit analysis of sterile neutrino models incorporating new MiniBooNE data, highlighting the challenges and limitations of (3+1), (3+2), and (3+3) schemes.

Findings

(3+1) models are more disfavored by new data

(3+2) models can reconcile MiniBooNE and LSND but face tension with other experiments

Adding a third sterile neutrino does not significantly improve the fit

Abstract

In view of the recent results from the MiniBooNE experiment we revisit the global neutrino oscillation fit to short-baseline neutrino data by adding one, two or three sterile neutrinos with eV-scale masses to the three Standard Model neutrinos. We find that four-neutrino oscillations of the (3+1) type, which have been only marginally allowed before the recent MiniBooNE results, become even more disfavored with the new data. In the framework of so-called (3+2) five-neutrino mass schemes the MiniBooNE results can be nicely reconciled with the LSND appearance evidence thanks to the possibility of CP violation available in such oscillation schemes; however, the tension between appearance and disappearance experiments represents a serious problem in (3+2) schemes, so that these models are ultimately not viable. This tension remains also when a third sterile neutrino is added, and we do not find a significant improvement of the global fit in a (3+3) scheme.