03 Aug 2009
The recent discovery of the single top quark by the CDF and DZero collaborations at the Department of Energy’s Fermi National Accelerator Laboratory (Fermilab) in the US has caused much excitement and confirms important parameters of particle physics, including the total number of quarks.
Previously top quarks have been observed only when produced in pairs. Now researchers using two of Fermilab’s detectors have announced that they have detected single top quarks.
The techniques used to find the singleton quarks could help to identify other rare particles, such as the Higgs boson, the scientists say.
A team of physicists from The University of Manchester were involved in the analysis that produced this finding.
They are Professor Stefan Soldner-Rembold, who is leader of the Scientific Program of the DZero experiment, Dr Christian Schwanenberger, Leader of the DZero Top Physics Working Group and Dr Yvonne Peters, a member of the Review Committee for the analysis.
Quarks are fundamental particles of matter that come in six varieties known as “flavours.” Ordinary matter consists mostly of two quark flavours, the “up” and “down” quarks that make up protons and neutrons. Other quarks are found in exotic subatomic particles or are created in high-energy collisions in particle accelerators. The top quark was the last flavour to be discovered experimentally, in 1995.
Since that time, the two groups at Fermilab, using the CDF and the DZero detectors, have combed through data from billions upon billions of particle collisions, looking for the unique features that would signal a single top quark.
But only about one in every 20 billion collisions produces a single top quark, and that weak signal easily gets lost in the background of other particle debris.
The sophisticated data analysis used to find the single top quarks could help scientists make sense of the results of other particle collision experiments, the researchers say.
The Higgs is a so-far hypothetical particle that most theorists believe is necessary to endow other subatomic particles with mass. Its discovery is being pursued at Fermilab and is also a prime goal for the Large Hadron Collider in Geneva.
For more information please contact Alex Waddington, Media Relations Officer, Tel 0161 275 8387.
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