Sterile neutrinos after the first MiniBooNE results
Abstract
Description
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.
5 pages, LaTeX file using jpconf style, 3 figures included. Proceedings of "The 2007 Europhysics Conference on High Energy Physics", Manchester, England, July 19-25, 2007. Typos corrected
5 pages, LaTeX file using jpconf style, 3 figures included. Proceedings of "The 2007 Europhysics Conference on High Energy Physics", Manchester, England, July 19-25, 2007. Typos corrected