Measurement of the helicity of W bosons in top-quark decays

We measure the branching fraction of the top quark to longitudinally and right-handed polarized W bosons, F0 and F+, using approximately 200pb-1 of p̄p collisions collected by the CDF II detector. We analyze two quantities sensitive to the W helicity: the invariant mass of the charged lepton and the...

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Bibliographic Details
Main Authors: Abulencia, A, Acosta, D, Adelman, J, Affolder, T, Akimoto, T, Albrow, MG, Ambrose, D, Amerio, S, Amidei, D, Anastassov, A, Anikeev, K, Annovi, A, Antos, J, Aoki, M, Apollinari, G, Arguin, J, Arisawa, T, Artikov, A, Ashmanskas, W, Attal, A, Azfar, F, Azzi-Bacchetta, P, Azzurri, P, Bacchetta, N, Bachacou, H
Format: Journal article
Language:English
Published: 2006
Description
Summary:We measure the branching fraction of the top quark to longitudinally and right-handed polarized W bosons, F0 and F+, using approximately 200pb-1 of p̄p collisions collected by the CDF II detector. We analyze two quantities sensitive to the W helicity: the invariant mass of the charged lepton and the bottom-quark jet in the decay t→Wb→ νb (where =e or μ), and the transverse momentum of the charged lepton. Constrained fits yield F0=0.74-0.34+0.22, and F+<0.27 at the 95% confidence level. These measurements are consistent with the standard model predictions. © 2006 The American Physical Society.