Number 24 (Story #1), 7 March 1991 by Phillip F. Schewe and Ben Stein AXIONS WITH A MASS OF 3 eV TO 8 eV have been ruled out by an astronomical search carried out at Kitt Peak Observatory. The Standard Model of particle physics calls for the existence of axions, which help to preserve certain symmetries pertaining to the strong nuclear force, but does not prescribe their mass. Theoretical arguments suggest two axion mass "windows": 10-6 to 10-3 eV and 3 to 8 eV. Cosmologists are also interested in axions as a possible constituent of dark matter. University of Chicago scientists (Michael S. Turner, 312-702-7974) sought evidence for the 3-8-eV axions in the form of photons (from the decay of the axions) in three rich galactic clusters. The lack of such photons seems to have closed the 3-8-eV axion window. (Physical Review Letters, 18 March.)