Melting nuclei re-create Big Bang broth.A powerful particle accelerator in Switzerland may have briefly reproduced an ancient state of matter that pervaded the universe in the first microseconds after its birth, researchers have announced. If confirmed, the findings from the European Laboratory for Particle Physics (CERN CERN or European Organization for Nuclear Research, nuclear and particle physics research center straddling the French-Swiss border W of Geneva, Switzerland. ) in Geneva Geneva, canton and city, Switzerland Geneva (jənē`və), Fr. Genève, canton (1990 pop. 373,019), 109 sq mi (282 sq km), SW Switzerland, surrounding the southwest tip of the Lake of Geneva. indicate that scientists have glimpsed a substance governed by titanic effects called color forces. Researchers are eager to study properties of the bizarre material, which may also exist inside collapsed stars known as neutron stars. CERN investigators smashed lead nuclei flying at nearly light's speed into other nuclei in fixed targets. The collisions produced fireballs 100,000 times hotter than the sun's core and 20 times the density of an atom's nucleus. In such microfurnaces, theorists propose, protons and neutrons may dissolve and momentarily set free a furious swarm, or plasma, of quarks and gluons Gluons The hypothetical force particles believed to bind quarks into “elementary” particles. Although theoretical models in which the strong interactions of quarks are mediated by gluons have been successful in predicting, interpreting, and . Quarks possess a characteristic that physicists call color, which is loosely analogous to electric charge. Under normal conditions the potent color force keeps quarks and gluons tightly confined within the nuclear particles. Researchers have sought the quark-gluon plasma since at least the mid-1980s (SN: 10/8/88, p. 229). In their Feb. 10 announcement, the CERN teams reported finding traces perhaps not of the plasma itself-which has a very narrow scientific definition-but of something closely akin to it. "All that we know is that we have evidence for a state in which quarks and gluons are deconfined," says Federico Antinori of the Instituto Nazionale di Fisica Nucleare in Padova, Italy. Since 1994, seven separate CERN teams have studied lead-lead and lead-gold collisions at the laboratory's Super Proton Synchrotron The Super Proton Synchrotron (SPS) is a particle accelerator at CERN. Originally specified as a 300 GeV proton machine, the SPS was actually built to be capable of 400GeV, an operating energy it achieved on the official commissioning date of 17 June 1976. (SPS (Standby Power System) A UPS system that switches to battery backup upon detection of power failure. See UPS. SPS - Symbolic Programming System. Assembly language for IBM 1620. ) accelerator. Some of those groups have previously reported findings that also hinted, although less strongly, at the quark-gluon plasma (SN: 9/21/96, p. 190). For the latest announcement, all the teams put their most up-to-date findings together like pieces of a puzzle, Antinori says. "Some individual signals may be controversial, but when you fit the picture together, the evidence is compelling," he argues. "All this agrees with what would be expected," concurs Johann Rafelski at the University of Arizona (body, education) University of Arizona - The University was founded in 1885 as a Land Grant institution with a three-fold mission of teaching, research and public service. in Tucson. "CERN has done great, significant work." Some physicists, however, remain unconvinced. "The important thing is the evidence for deconfined matter. I don't feel that it is compelling," comments James Nagle of Columbia University. Although he says the SPS research is of high quality, Nagle contends that many other physicists share his skepticism. The timing of the announcement has also raised eyebrows. Next month, the new Relativistic Heavy Ion Collider The Relativistic Heavy Ion Collider (RHIC, pronounced like "rick", IPA: /ˈrɪk/) is a heavy-ion collider located at and operated by Brookhaven National Laboratory (BNL) in Upton, New York. (RHIC RHIC Relativistic Heavy Ion Collider (Brookhaven National Lab) RHIC Radio Hypnotic Intracerebral Control RHIC Radiation Hardened Integrated Circuit ) at Brookhaven National Laboratory Brookhaven National Laboratory, scientific research center, at Upton (town of Brookhaven), Long Island, N.Y. It was founded in 1947 by Associated Universities, a management corporation sponsored by nine eastern U.S. universities. in Upton, N.Y., begins its much-heralded search for the quark-gluon plasma. CERN reports measurements indicating that SPS packed sufficient wallop to make a quark-gluon plasma. Other signs, also indirect, include anomalous abundances of certain quark types within particles formed when fireballs cooled. When CERN scientists combed their data for direct evidence, however, such as the gamma rays that physicists expect such plasma to emit, the signals they identified were unconvincing. Stronger signs could show up soon at the new collider col`lid´er n. 1. (Physics) a |
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