Fermilab physicists discover rare single top quarks

Structure of the atom

Scientists at the Fermi National Accelerator Laboratory, in Batavia, IL,
have identified the production of the elusive single top quark. Fourteen years ago, this very month, the top quark was discovered at the same lab, but in pairs of top and antimatter-top quarks. Now, for the first time we have observed the top quark without its antimatter partner!
                                                                   
Quarks are fundamental particles of matter that come in six different “flavors”. This is according to the Standard Model of particle physics which is a theory of elementary particles and forces in nature. Ordinary matter consists mostly of two quark flavors, the “up” and “down” quarks that make up the protons and neutrons in an atom. Other quarks are found in exotic sub-atomic particles or get created for very brief moments in high-energy collisions in particle accelerators. The Standard Model has witnessed spectacular phenomenological success since the mid-20th century, but a few of its predictions still remain to be validated by experiments. Production of single top quarks was one such hypothesis. Searching for single top quarks was more difficult than finding a needle in a hay-stack. Only one in every 20 billion proton-antiproton collisions produces a single top quark. In addition, the signal is easily mimicked by other “background” processes that occur at much higher rates. The recent identification of single top quarks is a breakthrough in isolating putative signals from overwhelming backgrounds, and has put yet another piece of the Standard Model puzzle into its place.

Although the goal of particle physics is to understand nature at a fundamental level, research in this field has produced practical benefits such as cancer treatment and the invention of the world wide web. The sophisticated pattern-recognition and data-analysis techniques developed for the single-top search have implications in several fields including medical imaging and materials science, explains Dr. Supriya Jain. Dr. Jain is a Wheaton resident, and has played a central role in this analysis, and is one of about 550 physicists from 90 institutions in 18 countries who work on the DZero experiment at Fermilab. DZero is one of the two collider experiments at Fermilab (the other is named "CDF"), both of which are now intensifying  their hunt for the “God particle”, the Higgs boson, the so-far hypothetical particle that most physicists believe provides masses to all other particles. The discovery of the Higgs boson is  also a prime goal of the Large Hadron Collider, in Geneva, Switzerland, that is scheduled to begin particle collisions later this year. The Large Hadron Collider would have seven times more energy than the Collider at Fermilab, and is expected to either validate or rule out a large number of theoretical predictions, and bring mankind closer to answering: What is the world made of? What holds it together??

For more information on:
- basics of particle physics, see: www.particleadventure.org
- Fermilab, see: www.fnal.gov
- benefits of particle physics, read: www.symmetrymagazine.org/pdfs/200812/dec_2008.pdf