Measurement of the single-top-quark production cross section at CDF

Abstract

We report a measurement of the single-top-quark production cross section in 2.2fb-1 of pp̄ collision data collected by the Collider Detector at Fermilab at s=1.96TeV. Candidate events are classified as signal-like by three parallel analyses which use likelihood, matrix element, and neural network discriminants. These results are combined in order to improve the sensitivity. We observe a signal consistent with the standard model prediction, but inconsistent with the background-only model by 3.7 standard deviations with a median expected sensitivity of 4.9 standard deviations. We measure a cross section of 2.2-0.6+0.7(stat+syst)pb, extract the Cabibbo-Kobayashi-Maskawa matrix-element value |Vtb|=0.88-0.12+0.13(stat+syst)±0.07(theory), and set the limit |Vtb|>0.66 at the 95% C.L. © 2008 The American Physical Society.