Number 497 (Story #3), August 16, 2000 by Phillip F. Schewe and Ben Stein FIRST RESULTS FROM B FACTORIES were announced on July 31 at the International Conference in High Energy Physics in Osaka, Japan. B factories make lots of B and anti-B mesons, objects that contain a bottom or anti-bottom quark. Researchers believe that these mesons may provide the largest and clearest signals yet of CP violation, a phenomenon that helps explain why matter outnumbers antimatter in the universe. Studying differences in decays and other properties in their Bs and anti Bs, two international collaborations announced preliminary values of a parameter known as sin (2* beta)--with a nonzero value providing solid evidence for the occurrence of CP violation. Analyzing 74 candidate events from 7 million B meson pairs, the Belle team at Japan's KEK Lab (Shiro Suzuki, 011-81-52-789-2893, suzuki@hepl.phys.nagoya-u.ac.jp) announced a sin (2*beta) result of 0.45 +/- 0.44 +/- 0.45. Presenting 120 candidate events from 10 million B meson pairs, the BaBar collaboration at SLAC (David Hitlin, Caltech, 626-395-6694, hitlin@hep.caltech.edu) announced a preliminary value of 0.12 +/-0.37 (statistical)+/-0.09 (systematic)--which is actually consistent with no CP violation. However, all researchers stressed that errors are large at this stage, and will be reduced with more data in the next year or so. Both machines are running well; for example, SLAC's relatively recent B factory is already at 76 percent of its peak luminosity. These results are all consistent with each other, as well as earlier measurements at Fermilab (Update 405) and the Standard Model, which currently estimates a range of values from 0.66 to 0.84, but with much experimental and theoretical uncertainty.