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---------------------------------------------------------------------------- Physicists find elusive subatomic particle ---------------------------------------------------------------------------- NEW YORK (September 1, 1997 07:52 a.m. EDT) -- Physicists have found evidence for an unusual new kind of subatomic particle that may help them explain how the universe is stuck together. After a three-decade search, the world's first "exotic meson" has been detected in a particle accelerator at the Brookhaven National Laboratory in Upton, N.Y. Physicists announce the detection in Monday's issue of "Physics Review Letters." "This is a very satisfying confirmation for us," said Brookhaven physicist Suh-Urk Chung. In the standard model of physics, a theoretical body of knowledge that has accumulated over 30 years, three quarks make a proton or neutron and two can combine to make another subatomic particle known as a meson. Quarks are the most basic type of subatomic particle known. That standard model also predicted that quarks could combine in unusual ways to form what are known as exotic mesons. "If somebody eventually didn't find this it would be quite a problem," said Neil Cason, one of 51 physicists who collaborated on the exotic meson research. If the observation is confirmed, physicists said, the study of exotic mesons could reveal details of how quarks -- and thus everything in the universe -- are stuck together. These particles were difficult to observe, however, because of their rarity and the fact that they can only exist for about a trillionth of a trillionth of a second. The Brookhaven experiments didn't actually see an exotic meson, but found evidence for them in the debris created by a high-energy collision between particles. To make these collisions, physicists aimed a beam of particles called pi mesons at a tank of liquid hydrogen. About 500 times out of 40,000, Chung said, the collisions produced a pattern inconsistent with a regular meson. The debris had come from the decay of an exotic meson composed of four quarks, or possibly a particle made of two quarks and another type of subatomic beast known as a gluon. "It's certainly a very important result," said Ted Barnes, a physicist at the Oak Ridge National Laboratory and the University of Tennessee. "If it's confirmed it really would be the first." By MATT CRENSON, The Associated Press Copyright 1997 Nando.net Copyright 1997 The Associated Press <http://www.nando.net/newsroom/ntn/health/090197/health4_2832_noframes.html> ---------------------------------------------------------------------------- [log in to unmask]