Phys. Rev. Lett.
100,
062004
(2008)
[7 pages]
Model-Independent Measurement of the W-Boson Helicity in Top-Quark Decays at D0
V. M. Abazov et al. D0 Collaboration
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V. M. Abazov36, B. Abbott76, M. Abolins66, B. S. Acharya29, M. Adams52, T. Adams50, E. Aguilo6, S. H. Ahn31, M. Ahsan60, G. D. Alexeev36, G. Alkhazov40, A. Alton65,*, G. Alverson64, G. A. Alves2, M. Anastasoaie35, L. S. Ancu35, T. Andeen54, S. Anderson46, B. Andrieu17, M. S. Anzelc54, Y. Arnoud14, M. Arov61, M. Arthaud18, A. Askew50, B. Åsman41, A. C. S. Assis Jesus3, O. Atramentov50, C. Autermann21, C. Avila8, C. Ay24, F. Badaud13, A. Baden62, L. Bagby53, B. Baldin51, D. V. Bandurin60, S. Banerjee29, P. Banerjee29, E. Barberis64, A.-F. Barfuss15, P. Bargassa81, P. Baringer59, J. Barreto2, J. F. Bartlett51, U. Bassler18, D. Bauer44, S. Beale6, A. Bean59, M. Begalli3, M. Begel72, C. Belanger-Champagne41, L. Bellantoni51, A. Bellavance51, J. A. Benitez66, S. B. Beri27, G. Bernardi17, R. Bernhard23, I. Bertram43, M. Besançon18, R. Beuselinck44, V. A. Bezzubov39, P. C. Bhat51, V. Bhatnagar27, C. Biscarat20, G. Blazey53, F. Blekman44, S. Blessing50, D. Bloch19, K. Bloom68, A. Boehnlein51, D. Boline63, T. A. Bolton60, G. Borissov43, T. Bose78, A. Brandt79, R. Brock66, G. Brooijmans71, A. Bross51, D. Brown82, N. J. Buchanan50, D. Buchholz54, M. Buehler82, V. Buescher22, V. Bunichev38, S. Burdin43,†, S. Burke46, T. H. Burnett83, C. P. Buszello44, J. M. Butler63, P. Calfayan25, S. Calvet16, J. Cammin72, W. Carvalho3, B. C. K. Casey51, N. M. Cason56, H. Castilla-Valdez33, S. Chakrabarti18, D. Chakraborty53, K. M. Chan56, K. Chan6, A. Chandra49, F. Charles19,††, E. Cheu46, F. Chevallier14, D. K. Cho63, S. Choi32, B. Choudhary28, L. Christofek78, T. Christoudias44, S. Cihangir51, D. Claes68, Y. Coadou6, M. Cooke81, W. E. Cooper51, M. Corcoran81, F. Couderc18, M.-C. Cousinou15, S. Crépé-Renaudin14, D. Cutts78, M. Ćwiok30, H. da Motta2, A. Das46, G. Davies44, K. De79, S. J. de Jong35, E. De La Cruz-Burelo65, C. De Oliveira Martins3, J. D. Degenhardt65, F. Déliot18, M. Demarteau51, R. Demina72, D. Denisov51, S. P. Denisov39, S. Desai51, H. T. Diehl51, M. Diesburg51, A. Dominguez68, H. Dong73, L. V. Dudko38, L. Duflot16, S. R. Dugad29, D. Duggan50, A. Duperrin15, J. Dyer66, A. Dyshkant53, M. Eads68, D. Edmunds66, J. Ellison49, V. D. Elvira51, Y. Enari78, S. Eno62, P. Ermolov38, H. Evans55, A. Evdokimov74, V. N. Evdokimov39, A. V. Ferapontov60, T. Ferbel72, F. Fiedler24, F. Filthaut35, W. Fisher51, H. E. Fisk51, M. Ford45, M. Fortner53, H. Fox23, S. Fu51, S. Fuess51, T. Gadfort71, C. F. Galea35, E. Gallas51, E. Galyaev56, C. Garcia72, A. Garcia-Bellido83, V. Gavrilov37, P. Gay13, W. Geist19, D. Gelé19, C. E. Gerber52, Y. Gershtein50, D. Gillberg6, G. Ginther72, N. Gollub41, B. Gómez8, A. Goussiou56, P. D. Grannis73, H. Greenlee51, Z. D. Greenwood61, E. M. Gregores4, G. Grenier20, Ph. Gris13, J.-F. Grivaz16, A. Grohsjean25, S. Grünendahl51, M. W. Grünewald30, J. Guo73, F. Guo73, P. Gutierrez76, G. Gutierrez51, A. Haas71, N. J. Hadley62, P. Haefner25, S. Hagopian50, J. Haley69, I. Hall66, R. E. Hall48, L. Han7, P. Hansson41, K. Harder45, A. Harel72, R. Harrington64, J. M. Hauptman58, R. Hauser66, J. Hays44, T. Hebbeker21, D. Hedin53, J. G. Hegeman34, J. M. Heinmiller52, A. P. Heinson49, U. Heintz63, C. Hensel59, K. Herner73, G. Hesketh64, M. D. Hildreth56, R. Hirosky82, J. D. Hobbs73, B. Hoeneisen12, H. Hoeth26, M. Hohlfeld22, S. J. Hong31, S. Hossain76, P. Houben34, Y. Hu73, Z. Hubacek10, V. Hynek9, I. Iashvili70, R. Illingworth51, A. S. Ito51, S. Jabeen63, M. Jaffré16, S. Jain76, K. Jakobs23, C. Jarvis62, R. Jesik44, K. Johns46, C. Johnson71, M. Johnson51, A. Jonckheere51, P. Jonsson44, A. Juste51, E. Kajfasz15, A. M. Kalinin36, J. R. Kalk66, J. M. Kalk61, S. Kappler21, D. Karmanov38, P. A. Kasper51, I. Katsanos71, D. Kau50, R. Kaur27, V. Kaushik79, R. Kehoe80, S. Kermiche15, N. Khalatyan51, A. Khanov77, A. Kharchilava70, Y. M. Kharzheev36, D. Khatidze71, T. J. Kim31, M. H. Kirby54, M. Kirsch21, B. Klima51, J. M. Kohli27, J.-P. Konrath23, V. M. Korablev39, A. V. Kozelov39, D. Krop55, T. Kuhl24, A. Kumar70, S. Kunori62, A. Kupco11, T. Kurča20, J. Kvita9, F. Lacroix13, D. Lam56, S. Lammers71, G. Landsberg78, P. Lebrun20, W. M. Lee51, A. Leflat38, F. Lehner42, J. Lellouch17, J. Leveque46, J. Li79, Q. Z. Li51, L. Li49, S. M. Lietti5, J. G. R. Lima53, D. Lincoln51, J. Linnemann66, V. V. Lipaev39, R. Lipton51, Y. Liu7, Z. Liu6, A. Lobodenko40, M. Lokajicek11, P. Love43, H. J. Lubatti83, R. Luna3, A. L. Lyon51, A. K. A. Maciel2, D. Mackin81, R. J. Madaras47, P. Mättig26, C. Magass21, A. Magerkurth65, P. K. Mal56, H. B. Malbouisson3, S. Malik68, V. L. Malyshev36, H. S. Mao51, Y. Maravin60, B. Martin14, R. McCarthy73, A. Melnitchouk67, L. Mendoza8, P. G. Mercadante5, M. Merkin38, K. W. Merritt51, J. Meyer22,§, A. Meyer21, T. Millet20, J. Mitrevski71, J. Molina3, R. K. Mommsen45, N. K. Mondal29, R. W. Moore6, T. Moulik59, G. S. Muanza20, M. Mulders51, M. Mulhearn71, O. Mundal22, L. Mundim3, E. Nagy15, M. Naimuddin51, M. Narain78, N. A. Naumann35, H. A. Neal65, J. P. Negret8, P. Neustroev40, H. Nilsen23, H. Nogima3, S. F. Novaes5, T. Nunnemann25, V. O’Dell51, D. C. O’Neil6, G. Obrant40, C. Ochando16, D. Onoprienko60, N. Oshima51, J. Osta56, R. Otec10, G. J. Otero y Garzón51, M. Owen45, P. Padley81, M. Pangilinan78, N. Parashar57, S.-J. Park72, S. K. Park31, J. Parsons71, R. Partridge78, N. Parua55, A. Patwa74, G. Pawloski81, B. Penning23, M. Perfilov38, K. Peters45, Y. Peters26, P. Pétroff16, M. Petteni44, R. Piegaia1, J. Piper66, M.-A. Pleier22, P. L. M. Podesta-Lerma33,‡, V. M. Podstavkov51, Y. Pogorelov56, M.-E. Pol2, P. Polozov37, B. G. Pope66, A. V. Popov39, C. Potter6, W. L. Prado da Silva3, H. B. Prosper50, S. Protopopescu74, J. Qian65, A. Quadt22,§, B. Quinn67, A. Rakitine43, M. S. Rangel2, K. Ranjan28, P. N. Ratoff43, P. Renkel80, S. Reucroft64, P. Rich45, J. Rieger55, M. Rijssenbeek73, I. Ripp-Baudot19, F. Rizatdinova77, S. Robinson44, R. F. Rodrigues3, M. Rominsky76, C. Royon18, P. Rubinov51, R. Ruchti56, G. Safronov37, G. Sajot14, A. Sánchez-Hernández33, M. P. Sanders17, A. Santoro3, G. Savage51, L. Sawyer61, T. Scanlon44, D. Schaile25, R. D. Schamberger73, Y. Scheglov40, H. Schellman54, T. Schliephake26, C. Schwanenberger45, A. Schwartzman69, R. Schwienhorst66, J. Sekaric50, H. Severini76, E. Shabalina52, M. Shamim60, V. Shary18, A. A. Shchukin39, R. K. Shivpuri28, V. Siccardi19, V. Simak10, V. Sirotenko51, P. Skubic76, P. Slattery72, D. Smirnov56, J. Snow75, G. R. Snow68, S. Snyder74, S. Söldner-Rembold45, L. Sonnenschein17, A. Sopczak43, M. Sosebee79, K. Soustruznik9, B. Spurlock79, J. Stark14, J. Steele61, V. Stolin37, D. A. Stoyanova39, J. Strandberg65, S. Strandberg41, M. A. Strang70, M. Strauss76, E. Strauss73, R. Ströhmer25, D. Strom54, L. Stutte51, S. Sumowidagdo50, P. Svoisky56, A. Sznajder3, M. Talby15, P. Tamburello46, A. Tanasijczuk1, W. Taylor6, J. Temple46, B. Tiller25, F. Tissandier13, M. Titov18, V. V. Tokmenin36, T. Toole62, I. Torchiani23, T. Trefzger24, D. Tsybychev73, B. Tuchming18, C. Tully69, P. M. Tuts71, R. Unalan66, S. Uvarov40, L. Uvarov40, S. Uzunyan53, B. Vachon6, P. J. van den Berg34, R. Van Kooten55, W. M. van Leeuwen34, N. Varelas52, E. W. Varnes46, I. A. Vasilyev39, M. Vaupel26, P. Verdier20, L. S. Vertogradov36, M. Verzocchi51, F. Villeneuve-Seguier44, P. Vint44, P. Vokac10, E. Von Toerne60, M. Voutilainen68,**, R. Wagner69, H. D. Wahl50, L. Wang62, M. H. L. S Wang51, J. Warchol56, G. Watts83, M. Wayne56, M. Weber51, G. Weber24, L. Welty-Rieger55, A. Wenger42, N. Wermes22, M. Wetstein62, A. White79, D. Wicke26, G. W. Wilson59, S. J. Wimpenny49, M. Wobisch61, D. R. Wood64, T. R. Wyatt45, Y. Xie78, S. Yacoob54, R. Yamada51, M. Yan62, T. Yasuda51, Y. A. Yatsunenko36, K. Yip74, H. D. Yoo78, S. W. Youn54, J. Yu79, A. Zatserklyaniy53, C. Zeitnitz26, T. Zhao83, B. Zhou65, J. Zhu73, M. Zielinski72, D. Zieminska55, A. Zieminski55,††, L. Zivkovic71, V. Zutshi53, and E. G. Zverev38 (D0 Collaboration)
1Universidad de Buenos Aires, Buenos Aires, Argentina
2LAFEX, Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro, Brazil
3Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
4Universidade Federal do ABC, Santo André, Brazil
5Instituto de Física Teórica, Universidade Estadual Paulista, São Paulo, Brazil
6University of Alberta, Edmonton, Alberta, Canada, Simon Fraser University, Burnaby, British Columbia, Canada, York University, Toronto, Ontario, Canada, and McGill University, Montreal, Quebec, Canada
7University of Science and Technology of China, Hefei, People’s Republic of China
8Universidad de los Andes, Bogotá, Colombia
9Center for Particle Physics, Charles University, Prague, Czech Republic
10Czech Technical University, Prague, Czech Republic
11Center for Particle Physics, Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
12Universidad San Francisco de Quito, Quito, Ecuador
13LPC, Univ Blaise Pascal, CNRS/IN2P3, Clermont, France
14LPSC, Université Joseph Fourier Grenoble 1, CNRS/IN2P3, Institut National Polytechnique de Grenoble, France
15CPPM, IN2P3/CNRS, Université de la Méditerranée, Marseille, France
16LAL, Univ Paris-Sud, IN2P3/CNRS, Orsay, France
17LPNHE, IN2P3/CNRS, Universités Paris VI and VII, Paris, France
18DAPNIA/Service de Physique des Particules, CEA, Saclay, France
19IPHC, Université Louis Pasteur et Université de Haute Alsace, CNRS/IN2P3, Strasbourg, France
20IPNL, Université Lyon 1, CNRS/IN2P3, Villeurbanne, France and Université de Lyon, Lyon, France
21III. Physikalisches Institut A, RWTH Aachen, Aachen, Germany
22Physikalisches Institut, Universität Bonn, Bonn, Germany
23Physikalisches Institut, Universität Freiburg, Freiburg, Germany
24Institut für Physik, Universität Mainz, Mainz, Germany
25Ludwig-Maximilians-Universität München, München, Germany
26Fachbereich Physik, University of Wuppertal, Wuppertal, Germany
27Panjab University, Chandigarh, India
28Delhi University, Delhi, India
29Tata Institute of Fundamental Research, Mumbai, India
30University College Dublin, Dublin, Ireland
31Korea Detector Laboratory, Korea University, Seoul, Korea
32SungKyunKwan University, Suwon, Korea
33CINVESTAV, Mexico City, Mexico
34FOM-Institute NIKHEF and University of Amsterdam/NIKHEF, Amsterdam, The Netherlands
35Radboud University Nijmegen/NIKHEF, Nijmegen, The Netherlands
36Joint Institute for Nuclear Research, Dubna, Russia
37Institute for Theoretical and Experimental Physics, Moscow, Russia
38Moscow State University, Moscow, Russia
39Institute for High Energy Physics, Protvino, Russia
40Petersburg Nuclear Physics Institute, St. Petersburg, Russia
41Lund University, Lund, Sweden, Royal Institute of Technology and Stockholm University, Stockholm, Sweden, and Uppsala University, Uppsala, Sweden
42Physik Institut der Universität Zürich, Zürich, Switzerland
43Lancaster University, Lancaster, United Kingdom
44Imperial College, London, United Kingdom
45University of Manchester, Manchester, United Kingdom
46University of Arizona, Tucson, Arizona 85721, USA
47Lawrence Berkeley National Laboratory and University of California, Berkeley, California 94720, USA
48California State University, Fresno, California 93740, USA
49University of California, Riverside, California 92521, USA
50Florida State University, Tallahassee, Florida 32306, USA
51Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA
52University of Illinois at Chicago, Chicago, Illinois 60607, USA
53Northern Illinois University, DeKalb, Illinois 60115, USA
54Northwestern University, Evanston, Illinois 60208, USA
55Indiana University, Bloomington, Indiana 47405, USA
56University of Notre Dame, Notre Dame, Indiana 46556, USA
57Purdue University Calumet, Hammond, Indiana 46323, USA
58Iowa State University, Ames, Iowa 50011, USA
59University of Kansas, Lawrence, Kansas 66045, USA
60Kansas State University, Manhattan, Kansas 66506, USA
61Louisiana Tech University, Ruston, Louisiana 71272, USA
62University of Maryland, College Park, Maryland 20742, USA
63Boston University, Boston, Massachusetts 02215, USA
64Northeastern University, Boston, Massachusetts 02115, USA
65University of Michigan, Ann Arbor, Michigan 48109, USA
66Michigan State University, East Lansing, Michigan 48824, USA
67University of Mississippi, University, Mississippi 38677, USA
68University of Nebraska, Lincoln, Nebraska 68588, USA
69Princeton University, Princeton, New Jersey 08544, USA
70State University of New York, Buffalo, New York 14260, USA
71Columbia University, New York, New York 10027, USA
72University of Rochester, Rochester, New York 14627, USA
73State University of New York, Stony Brook, New York 11794, USA
74Brookhaven National Laboratory, Upton, New York 11973, USA
75Langston University, Langston, Oklahoma 73050, USA
76University of Oklahoma, Norman, Oklahoma 73019, USA
77Oklahoma State University, Stillwater, Oklahoma 74078, USA
78Brown University, Providence, Rhode Island 02912, USA
79University of Texas, Arlington, Texas 76019, USA
80Southern Methodist University, Dallas, Texas 75275, USA
81Rice University, Houston, Texas 77005, USA
82University of Virginia, Charlottesville, Virginia 22901, USA
83University of Washington, Seattle, Washington 98195, USA
Received 31 October 2007; revised 11 December 2007; published 14 February 2008
We present the first model-independent measurement of the helicity of W bosons produced in top quark decays, based on a 1 fb-1 sample of candidate tt̅ events in the dilepton and lepton plus jets channels collected by the D0 detector at the Fermilab Tevatron pp̅ Collider. We reconstruct the angle θ* between the momenta of the down-type fermion and the top quark in the W boson rest frame for each top quark decay. A fit of the resulting cosθ* distribution finds that the fraction of longitudinal W bosons f0=0.425±0.166(stat)±0.102(syst) and the fraction of right-handed W bosons f+=0.119±0.090(stat)±0.053(syst), which is consistent at the 30% C.L. with the standard model.
© 2008 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevLett.100.062004
DOI:
10.1103/PhysRevLett.100.062004
PACS:
14.65.Ha, 12.15.Ji, 14.70.Fm
*Visitor from Augustana College, Sioux Falls, SD, USA. †Visitor from The University of Liverpool, Liverpool, United Kingdom. ‡Visitor from ICN-UNAM, Mexico City, Mexico. §Visitor from II. Physikalisches Institut, Georg-August-University, Göttingen, Germany. **Visitor from Helsinki Institute of Physics, Helsinki, Finland. ††Deceased.
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