Number 79 (Story #1), May 8, 1992 by Phillip F. Schewe and Ben Stein THE ELECTRON ANTINEUTRINO MASS can be no larger than 8 eV. This new upper limit was established by Wolfgang Stoeffl at Livermore who studied the beta decay of tritium, an experiment in which the neutrino's mass (or at least an upper limit) is inferred from a careful energy accounting for a process in which a neutron inside a tritium nucleus decays into a proton, an electron, and an antineutrino. One unsettling aspect of the mass calculation is the fact that the square of the neutrino mass would seem to have a negative value, which is nonsense. Stoeffl, reporting his results at the recent APS meeting in Washington, D.C., said that other experimenters have encountered the same effect. Such calculational oddities sometimes lead scientists to suspect that "new physics" is at work. (Science News, 2 May 1992.)