Press Release

Scientists complete the top quark puzzle: Images

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Matteo Cremonesi, left, of the University of Oxford and the CDF collaboration, and Reinhard Schwienhorst of Michigan State University and the DZero collaboration present the joint discovery at a forum at Fermilab on Friday, Feb. 21. The two collaborations have observed the production of single top quarks in the s-channel, as seen in data collected from the Tevatron. Photo: Fermilab

This diagram shows the process for creating single top quarks through the s-channel. A quark from an incoming proton interacts in the Tevatron with an antiquark from an incoming antiproton, forming a W boson with much greater mass. This W boson then decays into a top quark and an antibottom quark, which can be seen in the CDF and DZero detectors. Visit this page for more data. Image: Fermilab

This graph shows the difficulty of separating the “signal” of a single s-channel top quark from the background “noise” in the collision data. The CDF and DZero experiments use sophisticated analysis techniques to accomplish this, and this result is the first-ever discovery to use a mix of data from both experiments. The black solid line represents the background prediction for other well-known particle interaction processes, with the points representing data recorded by CDF and DZero. The blue shaded area represents the prediction for the s-channel single top quark signal. The data agrees with the prediction only if the data is added to the background model. This confirms the existence of s-channel single top quark production. Visit this page for more data. Image: Fermilab

A night photo of Fermilab’s Tevatron collider. Photo: Fermilab

Fermilab’s CDF detector, just outside the collision hall. Photo: Fermilab

Fermilab’s DZero detector, inside the collision hall. Photo: Fermilab