An approximation that is often used in fits to reactor and atmospheric neutrino data and in some theoretical studies is to assume one dominant scale, Δm2, of neutrino mass squared differences, in particular, Δmatm 2 ∼ 3 × 10-3 eV2. Here we investigate the corrections to this approximation arising from the quantity Δmsol 2 relevant for solar neutrino oscillations, assuming the large mixing angle solution. We show that for values of sin2(2θ13) ∼ 10-2 (in the range of interest for long-baseline neutrino oscillation experiments with either intense conventional neutrino beams such as JHF-SuperK or a possible future neutrino factory) and for Δmsol 2 ∼ 10-4 eV2, the contributions to vμ → ve oscillations from both CP-conserving and CP-violating terms involving sin2(Δmsol 2L/(4E)) can be comparable to the terms involving sin2(Δmatm 2L/(4E)) retained in the one-Δm2 approximation. Accordingly, we emphasize the importance of performing a full three-flavor, two-Δm2 analysis of the data on vμ → ve oscillations in a conventional-beam experiment and ve → vμ, ve → vμ oscillations at a neutrino factory. We also discuss a generalized analysis method for the KamLAND reactor experiment, and note how the information from this experiment can be used to facilitate the analysis of the subsequent data on vμ → ve oscillations. Finally, we consider the analysis of atmospheric neutrino data and present calculations of matter effects in a three-flavor, two-Δm2 framework relevant to this data and to neutrino factory measurements.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics