Related papers: Neutrino Oscillations Induced by Two-loop Radiativ…
Deviations from expectations have been claimed for solar, atmospheric and high energy prompt neutrinos from charm decay. This information, supplemented only by the existing very good upper limits for oscillations of the $\nu_{\mu}$ at…
We examine the constraints on non-radiative decay of neutrinos from the observations of solar neutrino experiments. The standard oscillation hypothesis among three neutrinos solves the solar and atmospheric neutrino problems. Decay of a…
We show how two different scales for oscillations between $e$ and $\mu$ neutrinos, characterized by different mixing angles and effective mass scales, can arise in a simple and theoretically attractive framework. One scale characterizes…
I review the status of neutrino masses and mixings in the light of the solar and atmospheric neutrino data in the framework of two--, three-- and four neutrino mixing.
After a brief introduction to neutrino mass via the see-saw model I discuss neutrino mixing and oscillation, first in vacuum and then its matter enhancement. Then the solar and atmospheric neutrino oscillation data are briefly reviewed.…
The recently announced Super-Kamiokande data on atmospheric neutrino oscillation seems to require a maximal mixing between the $\nu_{\mu}$ and $\nu_{\tau}$ within the conventional three neutrino picture. It is then tempting to suggest as…
We discuss neutrino masses in the framework of a minimal extension of the minimal supersymmetric standard model (MSSM) consisting of an additional single right-handed neutrino superfield $N$ with a heavy Majorana mass $M$, which induces a…
The neutrino long wavelength (just-so) oscillation is reconsidered as a solution to the solar neutrino problem. In the light of the presently updated results of the four solar neutrino experiments, the data fit in the just-so scenario…
We consider the ``standard'' spectrum of the active neutrinos (characterized by strong mass hierarchy and small mixing) with additional sterile neutrino, $\nu_s$. The sterile neutrino mixes strongly with the muon neutrino, so that…
The neutrino oscillation hypothesis does a poor job of representing the atmospheric neutrino anomaly. The anomaly is observed over 4 decades in path length and at least a factor of 30 in energy. This restricts the potential oscillation…
The basics of neutrino oscillations is presented. Existing evidences of neutrino oscillations, obtained in the atmospheric and solar neutrino experiments, are considered. The new CHOOZ bound on the element $|U_{e3}|^{2}$, obtained from the…
Recent results from SuperKamiokande and SNO experiments have set severe constraints on possible mixings of a light sterile neutrino, \nu_s, with the three active species required for a simultaneous explanation of the solar, atmospheric and…
By using the $L_e$ - $L_\mu$ - $L_\tau$ symmetry, we construct an $SU(3)_L\times U(1)_N$ gauge model that provides two-loop radiative neutrino masses as well as one-loop radiative neutrino masses. The generic smallness of two-loop neutrino…
In the wake of the SuperKamiokande announcement of atmospheric neutrino oscillations which favor the large mixing of $\nu_\mu$ with $\nu_\tau$, there is considerable theoretical activity towards a possible understanding of the solar…
Assuming three flavour neutrino mixing takes place in vacuum, we investigate the possibility that the solar nu_e take part in MSW transitions in the Sun due to Delta m^2_{31} from 10^{-7} eV^2 to 10^{-4} eV^2, followed by long wave length…
The results of the MACRO experiment on atmospheric neutrino oscillations are presented and discussed. The data concern different event topologies with average neutrino energies of ~ 4 and ~ 50 GeV. The Multiple Coulomb Scattering of muons…
We discuss an extended $SU(2)\times U(1)$ model which naturally leads to mass scales and mixing angles relevant for understanding both the solar and atmospheric neutrino anomalies. No right-handed neutrinos are introduced in the model.The…
As the increasing of neutrino energy or matter density, the neutrino oscillation in matter may undergo "vacuum-dominated", "resonance" and "matter-dominated" three different stages successively. Neutrinos endure very different matter…
We propose simple phenomenological lepton mass matrices which describe the three neutrinos almost degenerate in mass, leading to a very large mixing angle between $\nu_\mu$ and $\nu_\tau$, as consistent with a recent report on atmospheric…
The minimal interpretation of the atmospheric neutrino data suggests that the muon neutrino oscillates into another species with a mixing angle close to the maximal $\pi/4$. In the Exact Parity Symmetric Model, both the muon and electron…