Word: positrons
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Dates: during 1980-1989
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Called the large electron-positron collider (LEP), it will smash together electrons and positrons -- "antimatter" particles that are similar to electrons except that their charge is positive rather than negative. From the debris of the collisions, which involve particles traveling at nearly the speed of light, physicists hope to get information that will solidify -- or upset -- their understanding of the fundamental building blocks of matter and energy. Says Carlo Rubbia, CERN's director general: "This is the main road in basic science. You never know where the main road is really going to take you." Agrees Steven Weinberg...
...unexpected is always possible, CERN physicists do have a specific quarry to start with. As soon as the LEP has been put through its paces, they will begin taking a hard look at a particle called the Z 0, which will emerge in great numbers from the electron-positron collisions. The discovery of the Z 0 and two related particles, W+ and W-, in 1982 and 1983 won a Nobel for CERN scientists Rubbia and Simon van der Meer. The three particles carry the weak nuclear force, one of the four fundamental forces of nature, which is responsible for radioactive...
...second rate. The Tevatron, an accelerator at Fermilab, near Chicago, that smashes together protons and antiprotons, is still the most powerful collider in the world, and the proposed superconducting supercollider, planned for Texas, will be more powerful still. Proton-antiproton collisions entail more energy than electron- positron collisions and thus are more likely to generate previously undiscovered particles. But proton-antiproton impacts generate more subatomic debris, which makes it harder to study the properties of individual particles carefully. For what Amaldi calls "precision physics," Europe could soon...
...cells may have died for the process to be reversed. "If we can come up with better diagnostic procedures, it might be possible to block the progress of AD chemotherapeutically in the next five years." says Gibbs of NIH One promising method is a new scanning process called PET (positron emission tomography), which measures glucose metabolism in living cells. PET-scan studies by Dr. David Kuhl of U.C.L.A., among others, have revealed drastic decreases in metabolism in the brains of AD patients. Kuhl hopes to develop an early diagnostic test so that AD patients can "receive treatment while their brains...
...give cross-sectional views of internal body structures, not just bones but soft tissues as well. But scanning by CAT (for computerized axial tomography) is limited to anatomy. It lets doctors see an organ's shape and form, but cannot tell how it is functioning. PET (for positron emission tomography) allows the physician to examine the brain and body in ways never before possible, providing metabolic portraits, and revealing the rate at which sick and healthy tissues consume biochemicals...