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Title
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Measurement of the helicity fractions of **W** bosons from top quark decays using fully reconstructed events with CDF II
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Author
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Institution/Organisation
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CDF Collaboration
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Abstract
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| We present a measurement of the fractions F0 and F+ of longitudinally polarized and right-handed W bosons in top-quark decays using data collected with the CDF II detector. The data set used in the analysis corresponds to an integrated luminosity of approximately 318 pb-1. We select tt̅ candidate events with one lepton, at least four jets, and missing transverse energy. Our helicity measurement uses the decay angle θ*, which is defined as the angle between the momentum of the charged lepton in the W boson rest frame and the W momentum in the top-quark rest frame. The cosθ* distribution in the data is determined by full kinematic reconstruction of the tt̅ candidates. We find F0=0.85-0.22+0.15(stat)±0.06(syst) and F+=0.05-0.05+0.11(stat)±0.03(syst), which is consistent with the standard model prediction. We set an upper limit on the fraction of right-handed W bosons of F+<0.26 at the 95% confidence level. |
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Language
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English
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Source (journal)
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Physical review : D : particles, fields, gravitation, and cosmology / American Physical Society. - Ridge, N.Y., 2004 - 2015
Physical review : D : particles and fields. - Lancaster, Pa, 1970 - 2003
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Publication
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Ridge, N.Y.
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American Physical Society
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2007
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ISSN
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1550-7998
[print]
1550-2368
[online]
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DOI
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10.1103/PHYSREVD.75.052001
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Volume/pages
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75
:5
(2007)
, p. 052001,1-052001,11
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ISI
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000245333000003
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Full text (Publisher's DOI)
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Full text (open access)
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