Number 205 (Story #3), December 1, 1994 by Phillip F. Schewe and Ben Stein MUON-MUON COLLIDERS are not even on the drawing boards yet. But some physicists, such as Robert Palmer of Brookhaven, believe muon machines might be an economical alternative to building long linear accelerators for generating TeV-energy beams of electrons and positrons. Linacs are popular with those who contemplate future accelerators because linacs avoid the grave loss of energy to synchrotron radiation suffered by circular facilities such as CERN's LEP collider. Muons are leptons, like electrons, but with a mass 200 times greater. Muons would shed much less energy than electrons in making myriad trips around a circular accelerator. This would allow machine engineers to retain the circular design, and along with it the ability for stored beams to interact with each other over and over, which is not the case with linacs. Major drawbacks to using muons are the difficulty in generating muons in the first place (they are produced from the decay of pions created when a proton beam is smashed into a target) and the fact that they are unstable, with a lifetime of only a millionth of a second. (CERN Courier, October 1994.)