Neutrino Anomalies and Quasi-Dirac neutrinos

Abstract

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 ${\nu }_e$ or ${\nu }_{\mu }$ 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_μ-L_τ-L_s symmetry. Specific form of L_e+L_μ-L_τ-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_μ-L_τ-L_s symmetry are discussed.

15 pages, LATEX, minor corrections; addition of few references

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• Neutrino anomalies and large extra dimensions

Cited by in corpus (5)

• Status of four-neutrino mass schemes: a global and unified approach to current neutrino oscillation data
• Constraining Mass Spectra with Sterile Neutrinos from Neutrinoless Double Beta Decay, Tritium Beta Decay and Cosmology
• Quasi Dirac neutrino oscillations
• Three Generation Neutrino Oscillation Parameters after SNO
• Quasi-Dirac neutrino oscillations at DUNE and JUNO