5 research outputs found
Neutrino Anomalies and Quasi-Dirac neutrinos
We discuss possibility of describing solar, atmospheric and LSND results with
four neutrinos forming two quasi-degenerate pairs. The simplest versions of
this 2+2 scheme with either or mixing exclusively with
sterile neutrino is disfavored by the SNO and atmospheric neutrino results
respectively. A generalized scheme with sterile state participating in both the
solar and atmospheric oscillations is still allowed. We show thasolar and
atmospheric oscillations is still allowed. We show that the complex pattern of
mixing needed for this purpose follows from a simple L_e+L_\mu-L_\tau-L_s
symmetry. Specific form of L_e+L_\mu-L_\tau-L_s symmetric mass matrix is
determined from experimental results. Two theoretical schemes which lead to
this form and a proper breaking of L_e+L_\mu-L_\tau-L_s symmetry are discussed.Comment: 15 pages, LATEX, minor corrections; addition of few reference
Quasi Goldstone Fermion As a Sterile Neutrino
The existence of sterile neutrino is hinted by simultaneous explanation of
diverse neutrino anomalies. We suggest that the quasi Goldstone fermions (QGF)
arising in supersymmetric theory as a result of spontaneous breaking of global
symmetry like the Peccei-Quinn symmetry or the lepton number symmetry can play
a role of the sterile neutrino. The smallness of mass of QGF ( eV) can be related to the specific choice of superpotential or
K\"ahler potential (e.g., no-scale kinetic terms for certain superfields).
Mixing of QGF with neutrinos implies the -parity violation. It can proceed
via the coupling of QGF with the Higgs supermultiplets or directly with the
lepton doublet. A model which accounts for the solar and atmospheric anomalies
and the dark matter is presented.Comment: 16 pages plus 3 figures include