Orateur
Mlle
Camilla Galloni
(University of Zurich)
Description
We present a measurement of the ratio of the top-quark branching fraction $R
= B (t -> Wb) /B (t -> Wq), where q represents quarks of type d, s or b, in the final state with two charged leptons, missing transverse energy and at least two jets. The measurement uses sqrt{s} =1.96 TeV proton-antiproton collision data collected with the Collider Detector at Fermilab during Run II, corresponding to an integrated luminosity of 8.7 fb^{-1}. We measure R=0.87 +- 0.07 (stat+syst) and extract the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element | V_{tb} | = 0.93 +- 0.04 (stat+syst) assuming three generations of quarks. Under the same assumption a lower limit on | V_{tb} | > 0.86 at 95% confidence level is set.
Author
Mlle
Camilla Galloni
(University of Zurich)
