Status of a hybrid three-neutrino interpretation of neutrino data

We re-analyse the non-standard interaction (NSI) solutions to the solar neutrino problem in the light of the latest solar as well as atmospheric neutrino data. The latter require oscillations (OSC), while the former do not. Within such a threeneutrino framework the solar and atmospheric neutrino sectors are connected not only by the neutrino mixing angle θ13 constrained by reactor and atmospheric data, but also by the flavour-changing (FC) and non-universal (NU) parameters accounting for the solar data. Since the NSI solution is energy-independent the spectrum is undistorted, so that the global analysis observables are the solar neutrino rates in all experiments as well as the Super-Kamiokande day-night measurements. We find that the NSI description of solar data is slightly better than that of the OSC solution and that the allowed NSI regions are determined mainly by the rate analysis. By using a few simplified ansätze for the NSI interactions we explicitly demonstrate that the NSI values indicated by the solar data analysis are fully acceptable also for the atmospheric data. In the appendix we present an updated analysis combining the latest data from all solar neutrino experiments with the first results from KamLAND. We show that, although NSI still gives an excellent description of the solar data, the inclusion of KamLAND excludes at more than 3σ the NSI hypothesis as a solution to the solar neutrino problem. Preprint submitted to Elsevier Science 1st February 2008