Accelerator, reactor and atmospheric neutrino data: a three-flavor oscillation analysis

Abstract

We perform a three-flavor oscillation analysis of accelerator, reactor and atmospheric neutrino results. Motivated by the experimental data, the mass squared differences are chosen to be Δ₁₂=Δ₁₃ in the range 0.5-10 eV² and Δ₂₃=10⁻² eV². In such a scenario, the oscillation probabilities for the accelerator and reactor neutrinos involve only two of the mixing angles and one mass scale. But the atmospheric neutrino oscillation is governed by both mass scales and all the three mixing angles. The greater latitude allowed by the scheme leads to some new and interesting solution regions for atmospheric neutrinos in addition to the two-flavor limits usually discussed. However, incorporating the constraints from the previous accelerator searches for neutrino oscillations, a very narrow range of allowed mixing angles survives. This zone is beyond the reach of the on-going accelerator experiments CHORUS and NOMAD with their projected sensitivity.