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Phys. Rev. Lett. 98, 181802 (2007) [8 pages]

Evidence for Production of Single Top Quarks and First Direct Measurement of |Vtb|

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V. M. Abazov et al. DØ Collaboration
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Received 22 December 2006; published 1 May 2007

The D0 Collaboration presents first evidence for the production of single top quarks at the Fermilab Tevatron pp̅ collider. Using a 0.9  fb-1 dataset, we apply a multivariate analysis to separate signal from background and measure σ(pp̅ →tb+X,tqb+X)=4.9±1.4  pb. The probability to measure a cross section at this value or higher in the absence of a signal is 0.035%, corresponding to a 3.4 standard deviation significance. We use the cross section measurement to directly determine the Cabibbo-Kobayashi-Maskawa matrix element that describes the Wtb coupling and find 0.68<|Vtb|≤1 at 95% C.L. within the standard model.

© 2007 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevLett.98.181802
DOI:
10.1103/PhysRevLett.98.181802
PACS:
14.65.Ha, 12.15.Hh, 13.85.Ni