Number 253 (Story #1), January 4, 1996 by Phillip F. Schewe and Ben Stein ANTIHYDROGEN ATOMS HAVE BEEN CREATED at CERN. Physicists from a Julich/Erlangen-Nuernberg/GSI/Genoa collaboration passed a beam of antiprotons through a jet of xenon gas. Occasionally, some of the antiproton's own energy can be converted into electron-positron pairs. In the case of nine events, the newly created positron's motion was well matched to that of the antiproton and they formed an atom, in effect an atom of antihydrogen. Antimatter has been produced in the lab artificially for decades; antiprotons, for example, were first produced in the 1950s. The positron was first discovered in the 1930s. But not until now have anti-atoms been made and detected. The Low Energy Antiproton Ring (LEAR) at CERN makes it possible to slow antiprotons down sufficiently to perform a variety of physics experiments, including the insertion of antiprotons into ordinary atoms and the creation of anti-atoms. In the present experiment, the anti-hydrogen atoms were not trapped, and very quickly annihilated with ordinary matter in the vicinity. Scientists at CERN hope soon to actually capture and study the new exotic atoms. First of all, one wants to be sure that all the physical laws that pertain to atoms---such as quantum mechanics---also govern the behavior of antimatter as well. (CERN press release, 4 Jan.)