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
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
收藏
页码:160 / 167
页数:8
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