Measurement of W-boson polarization in Top-Quark Decay in pp collisions at sqrt[s]=1.96  TeV.

We report measurements of the polarization of W bosons from top-quark decays using 2.7 fb{-1} of pp collisions collected by the CDF II detector. Assuming a top-quark mass of 175  GeV/c{2}, three measurements are performed. A simultaneous measurement of the fraction of longitudinal (f{0}) and right-h...

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Bibliographic Details
Main Authors: Aaltonen, T, Adelman, J, Alvarez González, B, Amerio, S, Amidei, D, Anastassov, A, Annovi, A, Antos, J, Apollinari, G, Appel, J, Apresyan, A, Arisawa, T, Artikov, A, Asaadi, J, Ashmanskas, W, Attal, A, Aurisano, A, Azfar, F, Badgett, W, Barbaro-Galtieri, A, Barnes, V, Barnett, B, Barria, P, Bartos, P, Bauer, G
Format: Journal article
Language:English
Published: 2010
Description
Summary:We report measurements of the polarization of W bosons from top-quark decays using 2.7 fb{-1} of pp collisions collected by the CDF II detector. Assuming a top-quark mass of 175  GeV/c{2}, three measurements are performed. A simultaneous measurement of the fraction of longitudinal (f{0}) and right-handed (f{+}) W bosons yields the model-independent results f{0}=0.88±0.11(stat)±0.06(syst) and f{+}=-0.15±0.07(stat)±0.06(syst) with a correlation coefficient of -0.59. A measurement of f{0} [f{+}] constraining f{+} [f{0}] to its standard model value of 0.0 [0.7] yields f{0}=0.70±0.07(stat)±0.04(syst) [f{+}=-0.01±0.02(stat)±0.05(syst)]. All these results are consistent with standard model expectations. We achieve the single most precise measurements of f{0} for both the model-independent and model-dependent determinations.