Three-flavour neutrino oscillation update

Abstract

We review the present status of three-flavour neutrino oscillations, taking into account the latest available neutrino oscillation data presented at the Neutrino 2008 Conference. This includes the data released this summer by the MINOS collaboration, the data of the neutral current counter phase of the SNO solar neutrino experiment, as well as the latest KamLAND and Borexino data. We give the updated determinations of the leading 'solar' and 'atmospheric' oscillation parameters. We find from global data that the mixing angle θ 13 is consistent with zero within 0.9σ and we derive an upper bound of sin 2 θ 13 ≤ 0.035 (0.056) at 90% CL (3σ).

Interim Design Report

“…The measurement of the mixing angle θ 23 is still largely dominated by atmospheric neutrino data from Super-Kamiokande with a best-fit point close to maximal mixing. Small deviations from maximal mixing due to sub-leading, three-flavour effects (not included in the analysis of [36]) have been found in references [16,19,55], see table I. A comparison of these subtle effects can be found in reference [56].…”

“…Table I summarises the results of two recent global fits to world neutrino data from [19] and [36], both updated as of November 2010. Details of another recent analysis can be found in [37,38].…”

“…These improvements have been possible thanks mainly to the increased statistics, in particular the NC event sample in the LETA is increased by about 70% as a result of the decrease of the thresholds of 5 MeV and 5.5 MeV used in the Phase I Table I. Determination of three-neutrino oscillation parameters from 2010 global data [19,36]. For ∆m 2 31 and sin 2 θ 13 the upper (lower) row corresponds to inverted (normal) neutrino mass hierarchy.…”

“…[19] (updated) Ref. [36] in Phase II analyses respectively. Furthermore, energy resolution, background suppression, and systematic uncertainties have been improved.…”

“…This number indicates a slight tension between the sets, at the level of about 2.1σ. In the global analysis [36] only neutrino data are used from MINOS, whereas in the analysis in [19] both neutrino and anti-neutrino data are included. It is clear from figure 2 that the improvement in the quality of the fit when the anti-neutrino data are added is negligible.…”