Doug Michael
Senior Research Associate
Caltech

Data on neutrino oscillations, especially atmospheric neutrino data are
better than ever.  It is now very clear that something is happening to
neutrinos produced in the atmosphere as they traverse the earth and
furthermore that neutrino oscillations provide a good explanation.  The
addition of the solar neutrino problem and claimed appearance of
electron-antineutrinos in a muon antineutrino beam in the LSND
experiment add to the intrigue.  The question being asked in oscillation
experiments is evolving from "if there is an effect" to "what is the source
of the effect".  Over the last couple of years, the literature has filled with
competing explanations, some being tied to the fundamental physics of
grand unification.  In this talk, I will review the status of existing data on
neutrino oscillations, visit some of the proposed models to explain the
observed effects (with a focus on experimental observables that can
distinguish between the models) and discuss new experiments either
running now or in preparation which can add new information which
will help to clarify the picture over the next several years.  I will
particularly focus on the oscillation region associated with the atmospheric
neutrinos and the pursuit of "long-baseline" experiments to provide
precision measurements, in particular the MINOS (Main Injector Neutrino
Oscillation Search) experiment at Fermilab.