Measurement of W-boson helicity fractions in top-quark decays using cosθ

被引：14

作者：

Aaltonen, T. ^{[27
,28
]}

Adelman, J. ^{[16
]}

Akimoto, T. ^{[36
]}

Alvarez Gonzalez, B. ^{[14
]}

Amerio, S. ^{[53
,54
]}

Amidei, D. ^{[50
]}

Anastassov, A. ^{[58
]}

Annovi, A. ^{[23
]}

Antos, J. ^{[17
,18
]}

Apollinari, G. ^{[21
]}

Apresyan, A. ^{[43
]}

Arisawa, T. ^{[34
]}

Artikov, A. ^{[19
]}

Ashmanskas, W. ^{[21
]}

Attal, A. ^{[5
]}

Aurisano, A. ^{[37
]}

Azfar, F. ^{[52
]}

Badgett, W. ^{[21
]}

Barbaro-Galtieri, A. ^{[64
]}

Barnes, V. E. ^{[43
]}

Barnett, B. A. ^{[30
]}

Barria, P. ^{[48
,49
]}

Bartsch, V. ^{[62
]}

Bauer, G. ^{[65
]}

Beauchemin, P-H. ^{[66
,67
,68
,69
]}

Bedeschi, F. ^{[48
,49
]}

Beecher, D. ^{[62
]}

Behari, S. ^{[30
]}

Bellettini, G. ^{[48
,49
]}

Bellinger, J. ^{[32
]}

Benjamin, D. ^{[20
]}

Beretvas, A. ^{[21
]}

Beringer, J. ^{[64
]}

Bhatti, A. ^{[41
]}

Binkley, M. ^{[21
]}

Bisello, D. ^{[53
,54
]}

Bizjak, I. ^{[62
]}

Blair, R. E. ^{[3
]}

Blocker, C. ^{[9
]}

Blumenfeld, B. ^{[30
]}

Bocci, A. ^{[20
]}

Bodek, A. ^{[42
]}

Boisvert, V. ^{[42
]}

Bolla, G. ^{[43
]}

Bortoletto, D. ^{[43
]}

Boudreau, J. ^{[44
]}

Boveia, A. ^{[13
]}

Brau, B. ^{[13
]}

Bridgeman, A. ^{[29
]}

Brigliadori, L. ^{[7
,8
]}

机构：

[1] Univ Karlsruhe, Inst Expt Kernphys, D-76128 Karlsruhe, Germany

[2] Acad Sinica, Inst Phys, Taipei 11529, Taiwan

[3] Argonne Natl Lab, Argonne, IL 60439 USA

[4] Univ Athens, GR-15771 Athens, Greece

[5] Univ Autonoma Barcelona, Inst Fis Altes Energies, E-08193 Barcelona, Spain

[6] Baylor Univ, Waco, TX 76798 USA

[7] Univ Bologna, I-40127 Bologna, Italy

[8] Ist Nazl Fis Nucl Bologna, I-40127 Bologna, Italy

[9] Brandeis Univ, Waltham, MA 02254 USA

[10] Univ Calif Davis, Davis, CA 95616 USA

[11] Univ Calif Los Angeles, Los Angeles, CA 90024 USA

[12] Univ Calif San Diego, La Jolla, CA 92093 USA

[13] Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA

[14] Univ Cantabria, CSIC, Inst Fis Cantabria, E-39005 Santander, Spain

[15] Carnegie Mellon Univ, Pittsburgh, PA 15213 USA

[16] Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA

[17] Slovak Acad Sci, Inst Expt Phys, Kosice 04001, Slovakia

[18] Comenius Univ, Bratislava 84248, Slovakia

[19] Joint Inst Nucl Res, RU-141980 Dubna, Russia

[20] Duke Univ, Durham, NC 27708 USA

[21] Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA

[22] Univ Florida, Gainesville, FL 32611 USA

[23] Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy

[24] Univ Geneva, CH-1211 Geneva 4, Switzerland

[25] Univ Glasgow, Glasgow G12 8QQ, Lanark, Scotland

[26] Harvard Univ, Cambridge, MA 02138 USA

[27] Univ Helsinki, Dept Phys, Div High Energy Phys, FIN-00014 Helsinki, Finland

[28] Helsinki Inst Phys, FIN-00014 Helsinki, Finland

[29] Univ Illinois, Urbana, IL 61801 USA

[30] Johns Hopkins Univ, Baltimore, MD 21218 USA

[31] Yale Univ, New Haven, CT 06520 USA

[32] Univ Wisconsin, Madison, WI 53706 USA

[33] Wayne State Univ, Detroit, MI 48201 USA

[34] Waseda Univ, Tokyo 169, Japan

[35] Tufts Univ, Medford, MA 02155 USA

[36] Univ Tsukuba, Tsukuba, Ibaraki 305, Japan

[37] Texas A&M Univ, College Stn, TX 77843 USA

[38] Rutgers State Univ, Piscataway, NJ 08855 USA

[39] Ist Nazl Fis Nucl Trieste Udine, I-34100 Trieste, Italy

[40] Univ Trieste Udine, I-33100 Udine, Italy

[41] Rockefeller Univ, New York, NY 10021 USA

[42] Univ Rochester, Rochester, NY 14627 USA

[43] Purdue Univ, W Lafayette, IN 47907 USA

[44] Univ Pittsburgh, Pittsburgh, PA 15260 USA

[45] Univ Penn, Philadelphia, PA 19104 USA

[46] Univ Roma La Sapienza, I-00185 Rome, Italy

[47] Ist Nazl Fis Nucl, Sez Roma 1, I-00185 Rome, Italy

[48] Univ Siena, Univ Pisa, Ist Nazl Fis Nucl Pisa, I-56127 Pisa, Italy

[49] Scuola Normale Super Pisa, I-56127 Pisa, Italy

[50] Univ Michigan, Ann Arbor, MI 48109 USA

来源：

PHYSICS LETTERS B | 2009年 / 674卷 / 03期

基金：

瑞士国家科学基金会; 芬兰科学院; 美国国家科学基金会; 加拿大自然科学与工程研究理事会; 俄罗斯基础研究基金会; 英国科学技术设施理事会;

关键词：

Helicity; W boson; Top quark; SEMILEPTONIC DECAYS; QCD CORRECTIONS;

D O I：

10.1016/j.physletb.2009.02.040

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Fully reconstructed a t (t) over bar -> W(+)bW(-)(b) over bar -> l nu q (q) over bar 'b (b) over bar events are used to determine the fractions of right-handed (f(+)) and longitudinally polarized (f(0)) 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 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 f(0) = 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 f(0) fixed to the theoretically expected value of 0.70. Model-independent fits are also performed and simultaneously determine f(0) =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. (C) 2009 Elsevier B.V. All rights reserved.

引用

页码：160 / 167

页数：8

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