This paper reports on the first observation of electroweak production of single top quarks by the DZero and CDF collaborations. At Fermilabs 1.96 TeV proton-antiproton collider, a few thousand events are selected from several inverse femtobarns of da
ta that contain an isolated electron or muon and/or missing transverse energy, together with jets that originate from the decays of b quarks. Using sophisticated multivariate analyses to separate signal from background, the DZero collaboration measures a cross section sigma(ppbar->tb+X,tqb+X) = 3.94 +- 0.88 pb (for a top quark mass of 170 GeV) and the CDF collaboration measures a value of 2.3_0.6 -0.5 pb (for a top quark mass of 175 GeV). These values are consistent with theoretical predictions at next-to-leading order precision. Both measurements have a significance of 5.0 standard deviations, meeting the benchmark to be considered unambiguous observation.
After many years searching for electroweak production of top quarks, the Tevatron collider experiments have now moved from obtaining first evidence for single top quark production to an impressive array of measurements that test the standard model in
several directions. This paper describes measurements of the single top quark cross sections, limits set on the CKM matrix element |Vtb|, searches for production of single top quarks produced via flavor-changing neutral currents and from heavy W-prime and H+ boson resonances, and studies of anomalous Wtb couplings. It concludes with projections for future expected significance as the analyzed datasets grow.
