Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10725858 | Physics Letters B | 2009 | 8 Pages |
Abstract
Fully reconstructed tt¯âW+bWâb¯ââνqq¯â²bb¯ events are used to determine the fractions of right-handed (f+) and longitudinally polarized (f0) W bosons produced in top-quark decays. The helicity fractions are sensitive to the couplings and the Dirac structure of the Wtb vertex. This Letter reports measurements of the W-boson helicity fractions from two different methods using data corresponding to an integrated luminosity of 1.9fbâ1 of pp¯ collisions at a center-of-mass energy of 1.96 TeV collected by the CDF II detector operating at the Fermilab Tevatron. Combining the results from the two methods, we find f0=0.62±0.10(stat)±0.05(syst) under the assumption that f+=0, and f+=â0.04±0.04(stat)±0.03(syst) with f0 fixed to the theoretically expected value of 0.70. Model-independent fits are also performed and simultaneously determine f0=0.66±0.16(stat)±0.05(syst) and f+=â0.03±0.06(stat)±0.03(syst). All these results are consistent with standard model expectations.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Nuclear and High Energy Physics
Authors
CDF Collaboration CDF Collaboration, T. Aaltonen, J. Adelman, T. Akimoto, B. Álvarez González, S. Amerio, D. Amidei, A. Anastassov, A. Annovi, J. Antos, G. Apollinari, A. Apresyan, T. Arisawa, A. Artikov, W. Ashmanskas, A. Attal, A. Aurisano, F. Azfar,