Does a neutrino have mass?



Maybe. A new particle physics measurement reported at the spring (Washington, D.C.) meeting of the American Physical Society suggests that the elusive neutrino, a prominent member of the lepton class, may indeed be more of a quark. Frederick Reines of the University of California, Irvine, and his colleagues have described experiments done at the Savannah River reactor that, if confirmed, indicate mass and charge for the neutrino. The implications of this result could be overwhelming. Over and above the major reassessment of particle physics that will be required, the consequences on cosmic physics of the neutrino's having mass will be incredibly large.