To a packed auditorium at Fermilab on 11 April, the MiniBooNE collaboration presented the much-anticipated first results of a neutrino-oscillation experiment that began taking data five years ago. 1 The MiniBooNE experiment at Fermilab’s Tevatron was designed to confirm—or lay to rest—the most discordant and disputed note in an otherwise impressively harmonious extension of particle theory’s standard model. That extension is the simplest adaptation of the standard model to the undisputed existence of neutrino states with different nonzero masses.
The discordant note had first been struck in 1995 by an experiment at Los Alamos National Laboratory (see Physics Today, August 1995, page 20). The Liquid Scintillator Neutrino Detector (LSND) group at Los Alamos, using a neutrino beam produced by 800-MeV protons from the lab’s LAMPF accelerator, reported the observation of neutrino oscillation on a length scale of only 30 meters. All other observations of the oscillating metamorphosis of...
