Phys. Rev. D
75,
052001
(2007)
[11 pages]
Measurement of the helicity fractions of W bosons from top quark decays using fully reconstructed tt̅ events with CDF II
A. Abulencia et al. CDF Collaboration
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A. Abulencia24, J. Adelman13, T. Affolder10, T. Akimoto56, M. G. Albrow17, D. Ambrose17, S. Amerio44, D. Amidei35, A. Anastassov53, K. Anikeev17, A. Annovi19, J. Antos14, M. Aoki56, G. Apollinari17, J.-F. Arguin34, T. Arisawa58, A. Artikov15, W. Ashmanskas17, A. Attal8, F. Azfar43, P. Azzi-Bacchetta44, P. Azzurri47, N. Bacchetta44, W. Badgett17, A. Barbaro-Galtieri29, V. E. Barnes49, B. A. Barnett25, S. Baroiant7, V. Bartsch31, G. Bauer33, F. Bedeschi47, S. Behari25, S. Belforte55, G. Bellettini47, J. Bellinger60, A. Belloni33, D. Benjamin16, A. Beretvas17, J. Beringer29, T. Berry30, A. Bhatti51, M. Binkley17, D. Bisello44, R. E. Blair2, C. Blocker6, B. Blumenfeld25, A. Bocci16, A. Bodek50, V. Boisvert50, G. Bolla49, A. Bolshov33, D. Bortoletto49, J. Boudreau48, A. Boveia10, B. Brau10, L. Brigliadori5, C. Bromberg36, E. Brubaker13, J. Budagov15, H. S. Budd50, S. Budd24, S. Budroni47, K. Burkett17, G. Busetto44, P. Bussey21, K. L. Byrum2, S. Cabrera16,h, M. Campanelli20, M. Campbell35, F. Canelli17, A. Canepa49, S. Carillo18,b, D. Carlsmith60, R. Carosi47, M. Casarsa55, A. Castro5, P. Catastini47, D. Cauz55, M. Cavalli-Sforza3, A. Cerri29, L. Cerrito43,f, S. H. Chang28, Y. C. Chen1, M. Chertok7, G. Chiarelli47, G. Chlachidze15, F. Chlebana17, I. Cho28, K. Cho28, D. Chokheli15, J. P. Chou22, G. Choudalakis33, S. H. Chuang60, K. Chung12, W. H. Chung60, Y. S. Chung50, T. Chwalek26, M. Ciljak47, C. I. Ciobanu24, M. A. Ciocci47, A. Clark20, D. Clark6, M. Coca16, G. Compostella44, M. E. Convery51, J. Conway7, B. Cooper36, K. Copic35, M. Cordelli19, G. Cortiana44, F. Crescioli47, C. Cuenca Almenar7, J. Cuevas11,e, R. Culbertson17, J. C. Cully35, D. Cyr60, S. DaRonco44, M. Datta17, S. D’Auria21, T. Davies21, M. D’Onofrio3, D. Dagenhart6, P. de Barbaro50, S. De Cecco52, A. Deisher29, G. De Lentdecker50,‡, M. Dell’Orso47, F. Delli Paoli44, L. Demortier51, J. Deng16, M. Deninno5, D. De Pedis52, P. F. Derwent17, G. P. Di Giovanni45, C. Dionisi52, B. Di Ruzza55, J. R. Dittmann4, P. DiTuro53, C. Dörr26, S. Donati47, M. Donega20, P. Dong8, J. Donini44, T. Dorigo44, S. Dube53, J. Efron40, R. Erbacher7, M. Erdmann26, D. Errede24, S. Errede24, R. Eusebi17, H. C. Fang29, S. Farrington30, I. Fedorko47, W. T. Fedorko13, R. G. Feild61, M. Feindt26, J. P. Fernandez32, R. Field18, G. Flanagan49, A. Foland22, S. Forrester7, G. W. Foster17, M. Franklin22, J. C. Freeman29, I. Furic13, M. Gallinaro51, J. Galyardt12, J. E. Garcia47, F. Garberson10, A. F. Garfinkel49, C. Gay61, H. Gerberich24, D. Gerdes35, S. Giagu52, P. Giannetti47, A. Gibson29, K. Gibson48, J. L. Gimmell50, C. Ginsburg17, N. Giokaris15,*, M. Giordani55, P. Giromini19, M. Giunta47, G. Giurgiu12, V. Glagolev15, D. Glenzinski17, M. Gold38, N. Goldschmidt18, J. Goldstein43,†, A. Golossanov17, G. Gomez11, G. Gomez-Ceballos11, M. Goncharov54, O. González32, I. Gorelov38, A. T. Goshaw16, K. Goulianos51, A. Gresele44, M. Griffiths30, S. Grinstein22, C. Grosso-Pilcher13, R. C. Group18, U. Grundler24, J. Guimaraes da Costa22, Z. Gunay-Unalan36, C. Haber29, K. Hahn33, S. R. Hahn17, E. Halkiadakis53, A. Hamilton34, B.-Y. Han50, J. Y. Han50, R. Handler60, F. Happacher19, K. Hara56, M. Hare57, S. Harper43, R. F. Harr59, R. M. Harris17, M. Hartz48, K. Hatakeyama51, J. Hauser8, A. Heijboer46, B. Heinemann30, J. Heinrich46, C. Henderson33, M. Herndon60, J. Heuser26, D. Hidas16, C. S. Hill10,†, D. Hirschbuehl26, A. Hocker17, A. Holloway22, S. Hou1, M. Houlden30, S.-C. Hsu9, B. T. Huffman43, R. E. Hughes40, U. Husemann61, J. Huston36, J. Incandela10, G. Introzzi47, M. Iori52, Y. Ishizawa56, A. Ivanov7, B. Iyutin33, E. James17, D. Jang53, B. Jayatilaka35, D. Jeans52, H. Jensen17, E. J. Jeon28, S. Jindariani18, M. Jones49, K. K. Joo28, S. Y. Jun12, J. E. Jung28, T. R. Junk24, T. Kamon54, P. E. Karchin59, Y. Kato42, Y. Kemp26, R. Kephart17, U. Kerzel26, V. Khotilovich54, B. Kilminster40, D. H. Kim28, H. S. Kim28, J. E. Kim28, M. J. Kim12, S. B. Kim28, S. H. Kim56, Y. K. Kim13, N. Kimura56, L. Kirsch6, S. Klimenko18, M. Klute33, B. Knuteson33, B. R. Ko16, K. Kondo58, D. J. Kong28, J. Konigsberg18, A. Korytov18, A. V. Kotwal16, A. Kovalev46, A. C. Kraan46, J. Kraus24, I. Kravchenko33, M. Kreps26, J. Kroll46, N. Krumnack4, M. Kruse16, V. Krutelyov10, T. Kubo56, S. E. Kuhlmann2, T. Kuhr26, Y. Kusakabe58, S. Kwang13, A. T. Laasanen49, S. Lai34, S. Lami47, S. Lammel17, M. Lancaster31, R. L. Lander7, K. Lannon40, A. Lath53, G. Latino47, I. Lazzizzera44, T. LeCompte2, J. Lee50, J. Lee28, Y. J. Lee28, S. W. Lee54,g, R. Lefèvre3, N. Leonardo33, S. Leone47, S. Levy13, J. D. Lewis17, C. Lin61, C. S. Lin17, M. Lindgren17, E. Lipeles9, T. M. Liss24, A. Lister7, D. O. Litvintsev17, T. Liu17, N. S. Lockyer46, A. Loginov61, M. Loreti44, P. Loverre52, R.-S. Lu1, D. Lucchesi44, P. Lujan29, P. Lukens17, G. Lungu18, L. Lyons43, J. Lys29, R. Lysak14, E. Lytken49, P. Mack26, D. MacQueen34, R. Madrak17, K. Maeshima17, K. Makhoul33, T. Maki23, P. Maksimovic25, S. Malde43, G. Manca30, F. Margaroli5, R. Marginean17, C. Marino26, C. P. Marino24, A. Martin61, M. Martin21, V. Martin21,‡‡, M. Martínez3, T. Maruyama56, P. Mastrandrea52, T. Masubuchi56, H. Matsunaga56, M. E. Mattson59, R. Mazini34, P. Mazzanti5, K. S. McFarland50, P. McIntyre54, R. McNulty30,††, A. Mehta30, P. Mehtala23, S. Menzemer11,a, A. Menzione47, P. Merkel49, C. Mesropian51, A. Messina36, T. Miao17, N. Miladinovic6, J. Miles33, R. Miller36, C. Mills10, M. Milnik26, A. Mitra1, G. Mitselmakher18, A. Miyamoto27, S. Moed20, N. Moggi5, B. Mohr8, R. Moore17, M. Morello47, P. Movilla Fernandez29, J. Mülmenstädt29, A. Mukherjee17, Th. Muller26, R. Mumford25, P. Murat17, J. Nachtman17, A. Nagano56, J. Naganoma58, I. Nakano41, A. Napier57, V. Necula18, C. Neu46, M. S. Neubauer9, J. Nielsen29, T. Nigmanov48, L. Nodulman2, O. Norniella3, E. Nurse31, S. H. Oh16, Y. D. Oh28, I. Oksuzian18, T. Okusawa42, R. Oldeman30, R. Orava23, K. Osterberg23, C. Pagliarone47, E. Palencia11, V. Papadimitriou17, A. A. 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Seidel38, Y. Seiya42, A. Semenov15, L. Sexton-Kennedy17, A. Sfyrla20, M. D. Shapiro29, T. Shears30, P. F. Shepard48, D. Sherman22, M. Shimojima56,d, M. Shochet13, Y. Shon60, I. Shreyber37, A. Sidoti47, P. Sinervo34, A. Sisakyan15, J. Sjolin43, A. J. Slaughter17, J. Slaunwhite40, K. Sliwa57, J. R. Smith7, F. D. Snider17, R. Snihur34, M. Soderberg35, A. Soha7, S. Somalwar53, V. Sorin36, J. Spalding17, F. Spinella47, T. Spreitzer34, P. Squillacioti47, M. Stanitzki61, A. Staveris-Polykalas47, R. St. Denis21, B. Stelzer8, O. Stelzer-Chilton43, D. Stentz39, J. Strologas38, D. Stuart10, J. S. Suh28, A. Sukhanov18, H. Sun57, T. Suzuki56, A. Taffard24, R. Takashima41, Y. Takeuchi56, K. Takikawa56, M. Tanaka2, R. Tanaka41, M. Tecchio35, P. K. Teng1, K. Terashi51, J. Thom17,§, A. S. Thompson21, E. Thomson46, P. Tipton61, V. Tiwari12, S. Tkaczyk17, D. Toback54, S. Tokar14, K. Tollefson36, T. Tomura56, D. Tonelli47, S. Torre19, D. Torretta17, S. Tourneur45, W. Trischuk34, R. Tsuchiya58, S. Tsuno41, N. Turini47, F. Ukegawa56, T. Unverhau21, S. Uozumi56, D. Usynin46, S. Vallecorsa20, N. van Remortel23, A. Varganov35, E. Vataga38, F. Vázquez18,b, G. Velev17, G. Veramendi24, V. Veszpremi49, R. Vidal17, I. Vila11, R. Vilar11, T. Vine31, I. Vollrath34, I. Volobouev29,g, G. Volpi47, F. Würthwein9, P. Wagner54, R. G. Wagner2, R. L. Wagner17, J. Wagner26, W. Wagner26, R. Wallny8, S. M. Wang1, A. Warburton34, S. Waschke21, D. Waters31, W. C. Wester, III17, B. Whitehouse57, D. Whiteson46, A. B. Wicklund2, E. Wicklund17, G. Williams34, H. H. Williams46, P. Wilson17, B. L. Winer40, P. Wittich17,§, S. Wolbers17, C. Wolfe13, T. Wright35, X. Wu20, S. M. Wynne30, A. Yagil17, K. Yamamoto42, J. Yamaoka53, T. Yamashita41, C. Yang61, U. K. Yang13,c, Y. C. Yang28, W. M. Yao29, G. P. Yeh17, J. Yoh17, K. Yorita13, T. Yoshida42, G. B. Yu50, I. Yu28, S. S. Yu17, J. C. Yun17, L. Zanello52, A. Zanetti55, I. Zaw22, X. Zhang24, J. Zhou53, and S. Zucchelli5 (CDF Collaboration)
1Institute of Physics, Academia Sinica, Taipei, Taiwan 11529, Republic of China
2Argonne National Laboratory, Argonne, Illinois 60439, USA
3Institut de Fisica d’Altes Energies, Universitat Autonoma de Barcelona, E-08193, Bellaterra (Barcelona), Spain
4Baylor University, Waco, Texas 76798, USA
5Istituto Nazionale di Fisica Nucleare, University of Bologna, I-40127 Bologna, Italy
6Brandeis University, Waltham, Massachusetts 02254, USA
7University of California, Davis, Davis, California 95616, USA
8University of California, Los Angeles, Los Angeles, California 90024, USA
9University of California, San Diego, La Jolla, California 92093, USA
10University of California, Santa Barbara, Santa Barbara, California 93106, USA
11Instituto de Fisica de Cantabria, CSIC-University of Cantabria, 39005 Santander, Spain
12Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
13Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA
14Comenius University, 842 48 Bratislava, Slovakia; Institute of Experimental Physics, 040 01 Kosice, Slovakia
15Joint Institute for Nuclear Research, RU-141980 Dubna, Russia
16Duke University, Durham, North Carolina 27708
17Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA
18University of Florida, Gainesville, Florida 32611, USA
19Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, I-00044 Frascati, Italy
20University of Geneva, CH-1211 Geneva 4, Switzerland
21Glasgow University, Glasgow G12 8QQ, United Kingdom
22Harvard University, Cambridge, Massachusetts 02138, USA
23Division of High Energy Physics, Department of Physics, University of Helsinki and Helsinki Institute of Physics, FIN-00014, Helsinki, Finland
24University of Illinois, Urbana, Illinois 61801, USA
25The Johns Hopkins University, Baltimore, Maryland 21218, USA
26Institut für Experimentelle Kernphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany
27High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305, Japan
28Center for High Energy Physics: Kyungpook National University, Taegu 702-701, Korea; Seoul National University, Seoul 151-742, Korea; and SungKyunKwan University, Suwon 440-746, Korea
29Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
30University of Liverpool, Liverpool L69 7ZE, United Kingdom
31University College London, London WC1E 6BT, United Kingdom
32Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, E-28040 Madrid, Spain
33Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
34Institute of Particle Physics: McGill University, Montréal, Canada H3A 2T8; and University of Toronto, Toronto, Canada M5S 1A7
35University of Michigan, Ann Arbor, Michigan 48109, USA
36Michigan State University, East Lansing, Michigan 48824, USA
37Institution for Theoretical and Experimental Physics, ITEP, Moscow 117259, Russia
38University of New Mexico, Albuquerque, New Mexico 87131, USA
39Northwestern University, Evanston, Illinois 60208, USA
40The Ohio State University, Columbus, Ohio 43210, USA
41Okayama University, Okayama 700-8530, Japan
42Osaka City University, Osaka 588, Japan
43University of Oxford, Oxford OX1 3RH, United Kingdom
44University of Padova, Istituto Nazionale di Fisica Nucleare, Sezione di Padova-Trento, I-35131 Padova, Italy
45LPNHE, Universite Pierre et Marie Curie/IN2P3-CNRS, UMR7585, Paris, F-75252 France
46University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
47Istituto Nazionale di Fisica Nucleare Pisa, Universities of Pisa, Siena and Scuola Normale Superiore, I-56127 Pisa, Italy
48University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
49Purdue University, West Lafayette, Indiana 47907, USA
50University of Rochester, Rochester, New York 14627, USA
51The Rockefeller University, New York, New York 10021, USA
52Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1, University of Rome “La Sapienza,” I-00185 Roma, Italy
53Rutgers University, Piscataway, New Jersey 08855, USA
54Texas A&M University, College Station, Texas 77843, USA
55Istituto Nazionale di Fisica Nucleare, University of Trieste/ Udine, Italy
56University of Tsukuba, Tsukuba, Ibaraki 305, Japan
57Tufts University, Medford, Massachusetts 02155, USA
58Waseda University, Tokyo 169, Japan
59Wayne State University, Detroit, Michigan 48201, USA
60University of Wisconsin, Madison, Wisconsin 53706, USA
61Yale University, New Haven, Connecticut 06520, USA
Received 8 December 2006; published 15 March 2007
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.
© 2007 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevD.75.052001
DOI:
10.1103/PhysRevD.75.052001
PACS:
12.15.−y, 13.88.+e, 14.65.Ha, 14.70.Fm
*University of Athens †With visitors from University of Bristol ‡With visitors from University Libre de Bruxelles §With visitors from Cornell University **With visitors from University of Cyprus ††With visitors from University of Dublin ‡‡With visitors from University of Edinburgh aWith visitors from University of Heidelberg bWith visitors from Universidad Iberoamericana cWith visitors from University of Manchester dWith visitors from Nagasaki Institute of Applied Science eWith visitors from University de Oviedo fWith visitors from University of London, Queen Mary and Westfield College gWith visitors from Texas Tech University hWith visitors from IFIC(CSIC-Universitat de Valencia)
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