Neutrino oscillations in three- and four-flavor schemes
Institute of General and Nuclear Physics, Russian Research Centre ‘Kurchatov Institute’, pl. Kurchatova 1, Moscow, 123182, Russian Federation
We review some theoretical aspects of neutrino oscillations in the case where more than two neutrino flavors are involved. These include: approximate analytic solutions for 3-flavor (3f) oscillations in matter; matter effects in νμ \leftrightarrow ντ oscillations; 3f effects in oscillations of solar, atmospheric, reactor, and supernova neutrinos and in accelerator long-baseline experiments; CP and T violation in neutrino oscillations in the vacuum and in matter; the problem of Ue3; and 4f oscillations.