The original B. Pontecorvo idea of neutrino oscillations is discussed. Neutrino mixing and basics of neutrino oscillations in vacuum and in matter are considered. Recent evidences in favour of neutrino oscillations, obtained in the Super-Kamiokande, SNO, KamLAND and other neutrino experiments are discussed. Neutrino oscillations in the solar and atmospheric ranges of the neutrino mass-squared d...

In recent years, several underground neutrino observatories 1) 3) have reported that the atmospheric neutrino ratio, R ≡ (νμ + ν̄μ)/(νe + ν̄e), is significantly smaller than the theoretical expectations. This “atmospheric neutrino anomaly” can be explained by a neutrino oscillation hypothesis with an oscillation parameter region of ∆m2 ∼ 10−2eV2 and sin 2θ ∼ 1. The atmospheric neutrino anomaly ha...

Resonant spin-flavor (RSF) conversions of supernova neutrinos, which is induced by the interaction between the nonzero neutrino magnetic moment and supernova magnetic fields, are studied for both normal and inverted mass hierarchy. As the case for the pure matter-induced neutrino oscillation [Mikheyev-SmirnovWolfenstein (MSW) effect], we find that the RSF transitions are strongly dependent on t...

Resonant spin-flavour (RSF) conversions of supernova neutrinos, which is induced by the interaction between the nonzero neutrino magnetic moment and supernova magnetic fields, are studied for both normal and inverted mass hierarchy. As the case for the pure matter-induced neutrino oscillation (Mikheyev–Smirnov– Wolfenstein (MSW) effect), we find that the RSF transitions are strongly dependent o...

We have considered the effect of the reduction of the solar neutrino flux on earth due to the deflection of the charged neutrino by the magnetic field of the solar convective zone. The antisymmetry of this magnetic field about the plane of the solar equator induces the anisotropy of the solar neutrino flux thus creating the deficit of the neutrino flux on the earth. The deficit has been estimat...

The indications for neutrino oscillations from the atmospheric and solar neutrino anomalies and from the LSND experiment are now so overwhelming that the discourse in neutrino physics has changed. One no longer asks if these particles indeed oscillate, one rather debates the most plausible pattern of masses and mixing angles, and if the existence of a sterile neutrino is required. Of course, al...

We discuss the physics potential of future tritium β-decay experiments having a sensitivity to a neutrino mass ∼ √ |∆m23| ∼ 5 × 10−2 eV. The case of three-neutrino mixing is analised. A negative result of such an experiment would imply that the neutrino mass spectrum is of normal hierarchical type. The interpretation of a positive result would depend on the value of the lightest neutrino mass; ...

In the early Universe, or near a supernova core, neutrino flavor evolution may be affected by coherent neutrino-neutrino scattering. We develop a microscopic picture of this phenomenon. We show that coherent scattering does not lead to the formation of entangled states in the neutrino ensemble and therefore the evolution of the system can always be described by a set of one-particle equations. ...

The KEK to Kamioka long-baseline neutrino experiment (K2K) is the first accelerator-based experiment with hundreds of km neutrino path length. K2K focuses on the study of the existence of neutrino oscillations in νμ disappearance that is observed in atmospheric neutrinos. With nearly pure muon neutrino beam produced with 5.6 × 10 protons from 12 GeV PS on target, 56 neutrino events have been ob...

Although the first evidence for neutrino oscillations came from measurements on atmospheric neutrinos in underground experiments, neutrino oscillations have yet to be demonstrated in high energy neutrino telescopes, whose energy threshold is significantly higher. Recent studies have shown that a clean sample of atmospheric neutrinos with energies as low as 20 GeV can be isolated in the ANTARES ...