2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/39282A four-neutrino effective texture is described, where a sterile neutrino mixes nearly maximally with the electron neutrino and so, is responsible for the deficit of solar $ν_e $'s (according to the large-angle MSW solution or vacuum solution, of which the former is selected a posteriori). But, while maximal mixing of muon neutrino with tauon neutrino causes the deficit of atmospheric $ν_μ$'s, the original magnitude of LSND effect is reduced by as much as four orders, becoming unobservable.7 pages, no figures. Title expandedHigh Energy Physics - Phenomenologytext