INDIRECT NEUTRINO OSCILLATIONS

We show how two different scales for oscillations between e and mu neu trinos, characterized by different mixing angles and very different ef fective mass scales, can arise in a simple and theoretically attractiv e framework, so as to be relevant to both solar neutrino and accelerat or-reactor experiments. One scale characterizes direct oscillations, w hich can accommodate the MSW approach to the solar neutrino problem, w hereas the other can be considered as arising indirectly, through virt ual transitions involving the tau neutrino with a mass similar to 1 eV . This indirect transition allows the possibility of observable <((n)u )over bar>(mu) <-> <(nu)over bar>(e) oscillations at accelerator and r eactor energies. We discuss specifically the parameters suggested by a recent experiment at Los Alamos within this framework.