Atmospheric Neutrino Oscillation and a Phenomenological Lepton Mass Matrix

Abstract

We propose simple phenomenological lepton mass matrices which describe the three neutrinos almost degenerate in mass, leading to a very large mixing angle between $ν_μ$ and $ν_τ$, as consistent with a recent report on atmospheric neutrino oscillation from the Superkamiokande collaboration. Our matrix model also gives $ν_e-ν_μ$ mixing in agreement with the value required for neutrino oscillation to explain the solar neutrino problem.