Heavy finding.The most massive subatomic subatomic /sub·atom·ic/ (-ah-tom´ik) of or pertaining to the constituent parts of an atom. sub·a·tom·ic adj. 1. Of or relating to the constituents of the atom. 2. cousins of protons and neutrons ever detected have made fleeting appearances in a U.S. particle accelerator particle accelerator, apparatus used in nuclear physics to produce beams of energetic charged particles and to direct them against various targets. Such machines, popularly called atom smashers, are needed to observe objects as small as the atomic nucleus in studies . The weightiest parts of the particles--known as sigma-b baryons--are called bottom quarks, one of the six types of quarks that are fundamental constituents of matter. Physicists at Fermi National Accelerator Laboratory Fermi National Accelerator Laboratory (Fermilab), physical science research center located near Batavia, Ill., est. 1968 as the National Accelerator Laboratory, renamed 1974 in honor of Enrico Fermi. It was built on the site of the former village of Weston. in Batavia, Ill., announced the exotic particles' discovery at the lab on Oct. 23. The scientists found telltale traces of the sigma-bs in the debris produced by more than 100 trillion collisions of protons and antiprotons that had occurred in the accelerator in the past 5 years. "You think, 'What kinds of jewels can you build out of these quarks?'" says physicist Jacobo Konigsberg of the University of Florida University of Florida is the third-largest university in the United States, with 50,912 students (as of Fall 2006) and has the eighth-largest budget (nearly $1.9 billion per year). UF is home to 16 colleges and more than 150 research centers and institutes. in Gainesville, a spokesman for the discovery team. When the team examined their data, the researchers realized that the sought-after quark combinations had shown up. Ordinary matter, such as protons and neutrons, contains only up quarks and down quarks, whereas the sigma-bs each contain a bottom quark and either a pair of up quarks or a pair of down quarks. Once abundant in the Big Bang big bang Model of the origin of the universe, which holds that it emerged from a state of extremely high temperature and density in an explosive expansion 10 billion–15 billion years ago. , sigma-bs--and the bottom quarks that make them special--show up today only in high-energy events such as particle collisions, notes Fermilab physicist Rob Roser, also a spokesman for the sigma-b discoverers. Sigma-b particles weigh about sex times as much as protons. The prevailing theory of particle physics accurately predicted the sigma-b masses. It calls for still heftier baryons This is a list of baryons, which are the family of subatomic particles each made of three quarks. See also quark model. Antiparticles are not listed in the table; however, they simply would have all quarks changed to antiquarks, and their baryon number, that haven't yet been found.--P.W. |
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