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Bs Mesons Lend Clues To Missing Antimatter
Batavia IL (SPX) Mar 23, 2006 New preliminary data on the properties of a subatomic particle called a B_s meson suggest that the particle actually oscillates between matter and antimatter � something that if verified could help scientists understand why antimatter is almost nonexistent in the current universe, and perhaps provide the first tangible evidence for the scientific theory called supersymmetry. Scientists at the Department of Energy's Fermi National Accelerator Laboratory found that the oscillations of B-s (pronounced "B sub s") mesons represent one of nature's fastest rapid-fire processes - more than 17 trillion times per second. The team used the DZero detector at Fermilab, a superfast instrument on the facility's Tevatron collider � currently the highest-energy particle accelerator in the world. DZero found that B_s mesons oscillate at frequencies between 17 trillion and 21 trillion times per second � or between 17 and 21 picoseconds, The DZero team said the result, which is a measure of the oscillation or matter-antimatter mixing frequency of the particle, has a confidence level of 90 percent. That means it does not yet qualify as a formal discovery. Physicists accept such claims only if they have a confidence level of at least 99.99995 percent � or a 99.99995 percent chance the result can be reproduced. The scientists compiled the DZero data from more than 1 billion events from the Tevatron accelerator - a milestone in itself, they said, because the new research capitalized on significant luminosity improvements in the device. Based on those improvements, a collider-detector collaboration at Fermilab called CDF expects to produce results with even greater precision than DZero. "Not only is this an exciting result, but the analysis of (the) data set represents a major milestone for DZero." said team spokesman Jerry Blazey of Northern Illinois University. "Next, the Tevatron experiments can focus on obtaining a precise measurement of B_s mixing, which will tell us even more about the curious subatomic world where particles can spontaneously turn into their own antiparticles and back again." One of the greatest mysteries in cosmology is the apparent absence of antimatter in the universe. If matter and antimatter were created equally at the time of the Big Bang, the two states should have annihilated each other into pure energy. This did not happen, so scientists have been trying to use laboratory experiments to see whether the missing antimatter could be due to the oscillations of some forms of matter. Reporting in a paper submitted to Physical Review Letters, the DZero team said studying such processes can help solve the mystery of the missing antimatter, and DZero has made important progress in this direction. "We congratulate DZero on this step," said CDF spokesman Rob Roser of Fermilab. "We at CDF are looking forward to our result on a similar size data sample where, given our sensitivity, we expect to get even closer to a discovery." Related Links DZero FermiLab
Tiny Cannibal Stars - Miniature Versions Of Galactic Centers
Noordwijk, The Netherlands (SPX) Mar 23, 2006European astronomers said they have solved a mystery concerning vast clouds of superheated gas that whirl around miniature stars in the process of being devoured by the stars' powerful gravitational fields. |
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