Properties of the neutrino mixing matrix

Abstract

For neutrino mixing we propose to use the parameter set X _i (=|V _ei |²) and Ω _i (=ϵ _ijk |V _μj |²|V _τk |²), with two constraints. These parameters are directly measurable since the neutrino oscillation probabilities are their quadratic functions. Physically, the set Ω _i signifies a quantitative measure of μ–τ asymmetry. Available neutrino data indicate that all the Ω _i ’s are small (<O(10⁻¹)), but with large uncertainties. The behavior of Ω _i as functions of the induced neutrino mass in matter is found to be simple, which should facilitate the analyses of long baseline experiments.