First Measurement of the Ratio B (t →Wb)/ B (t → Wq) and Associated Limit on the Cabibbo-Kobayashi-Maskawa Element |V_tb|

Authors

• T. Affolder, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California
• Kenneth A. Bloom, University of Nebraska-LincolnFollow
• Collider Detector at Fermilab Collaboration

Document Type

Article

Date of this Version

4-9-2001

Comments

Published by American Physical Society. Phys. Rev. Lett. 86, 3233 (2001). http://prl.aps.org. Copyright © 2001 American Physical Society. Permission to use.

Abstract

We present the first measurement of the ratio of branching fractions R≡ B(t→ Wb)/B(t →Wq) from pp̅ collisions at √s =1.8 TeV. The data set corresponds to 109 pb^-1 of data recorded by the Collider Detector at Fermilab during the 1992–95 Tevatron run. We measure R=_-0.24^+0.31(stat + syst) or R >0.61 (0.56) at 90% (95)% C.L., in agreement with the standard model predictions. This measurement yields a limit on the Cabibbo-Kobayashi-Maskawa quark mixing matrix element |V_tb| under the assumption of three generations and unitarity.