Number 93 (Story #2), September 9, 1992 by Phillip F. Schewe and Ben Stein DOUBTS ABOUT A 17-KEV NEUTRINO are growing. Scientist at last month's International High Energy Physics meeting in Dallas discussed the results of the latest round of experiments seeking to confirm the existence of a 17-keV neutrino. All of them came up short. Eric Norman of LBL, using a solid-state detector, found positive signs for the 17-keV neutrino in the beta-decay of carbon-14, but not in iron-55. Takayoshi Oshima of the National Laboratory for High Energy Physics in Japan looked for evidence of the neutrino in the most sensitive mass spectrometer test designed yet, and found nothing. Finally, Stuart Freedman of LBL studied beta-decay of radioactive sulfur using a solid-state detector, and did not see any signs of the neutrino. Freedman went so far as to test the sensitivity of his detector by mixing in some carbon-14, which produces beta-decay electrons at slightly lower energies than in sulfur, and managed to produce a signal mimicking the 17-keV spike. Although the prospect of a superheavy neutrino now appears dead, physicists are still at a loss to explain why positive signals had previously shown up in six independent solid-state detector experiments. (Science, 22 August 1992.)