Title
Measurement of W-boson helicity fractions in top-quark decays using cos θ<sup>*</sup>
Date Issued
20 April 2009
Access level
open access
Resource Type
journal article
Author(s)
Aaltonen T.
Adelman J.
Akimoto T.
Álvarez González B.
Amerio S.
Amidei D.
Anastassov A.
Annovi A.
Antos J.
Apollinari G.
Apresyan A.
Arisawa T.
Artikov A.
Ashmanskas W.
Attal A.
Aurisano A.
Azfar F.
Badgett W.
Barbaro-Galtieri A.
Barnes V.E.
Barnett B.A.
Barria P.
Bartsch V.
Bauer G.
Beauchemin P.H.
Bedeschi F.
Beecher D.
Behari S.
Bellettini G.
Bellinger J.
Benjamin D.
Beretvas A.
Beringer J.
Bhatti A.
Binkley M.
Bisello D.
Bizjak I.
Blair R.E.
Blocker C.
Blumenfeld B.
Bocci A.
Bodek A.
Boisvert V.
Bolla G.
Bortoletto D.
Boudreau J.
Boveia A.
Brau B.
Bridgeman A.
Brigliadori L.
Bromberg C.
Brubaker E.
Budagov J.
Budd H.S.
Budd S.
Burke S.
Burkett K.
Busetto G.
Bussey P.
Buzatu A.
Byrum K.L.
Cabrera S.
Calancha C.
Campanelli M.
Campbell M.
Canelli F.
Canepa A.
Carls B.
Carlsmith D.
Carosi R.
Carrillo S.
Carron S.
Casal B.
Casarsa M.
Castro A.
Catastini P.
Cauz D.
Cavaliere V.
Cavalli-Sforza M.
Cerri A.
Cerrito L.
Chang S.H.
Chen Y.C.
Chertok M.
Chiarelli G.
Chlachidze G.
Chlebana F.
Cho K.
Chokheli D.
Chou J.P.
Choudalakis G.
Chuang S.H.
Chung K.
Chung W.H.
Chung Y.S.
Chwalek T.
Ciobanu C.I.
Ciocci M.A.
Clark A.
Clark D.
Publisher(s)
Elsevier
Abstract
Fully reconstructed t over(t, ̄) → W+ b W- over(b, ̄) → ℓ ν q over(q, ̄)′ b over(b, ̄) 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 1.9 fb- 1 of p over(p, ̄) 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+ = - 0.04 ± 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+ = - 0.03 ± 0.06 (stat) ± 0.03 (syst). All these results are consistent with standard model expectations. © 2009 Elsevier B.V.
Start page
160
End page
167
Volume
674
Issue
3
Language
English
OCDE Knowledge area
Física de partículas, Campos de la Física
Subjects
Scopus EID
2-s2.0-63349084114
Source
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
ISSN of the container
03702693
Sponsor(s)
We thank the Fermilab staff and the technical staffs of the participating institutions for their vital contributions. This work was supported by the US Department of Energy and National Science Foundation; the Italian Istituto Nazionale di Fisica Nucleare; the Ministry of Education, Culture, Sports, Science and Technology of Japan; the Natural Sciences and Engineering Research Council of Canada; the National Science Council of the Republic of China; the Swiss National Science Foundation; the A.P. Sloan Foundation; the Bundesministerium für Bildung und Forschung, Germany; the Korean Science and Engineering Foundation and the Korean Research Foundation; the Science and Technology Facilities Council and the Royal Society, UK; the Institut National de Physique Nucleaire et Physique des Particules/CNRS; the Russian Foundation for Basic Research; the Ministerio de Ciencia e Innovación, and Programa Consolider-Ingenio 2010, Spain; the Slovak R&D Agency; and the Academy of Finland.
Sources of information:
Directorio de Producción Científica
Scopus