Measurement of the polarisation of single top quarks and antiquarks produced in the t-channel at root s=13 TeV and bounds on the tWb dipole operator from the ATLAS experiment
文献类型：期刊论文
| 作者 | ATLAS Collaboration |
| 刊名 | JOURNAL OF HIGH ENERGY PHYSICS
 |
| 出版日期 | 2022 |
| 期号 | 11页码:40 |
| ISSN号 | 1029-8479 |
| 关键词 | Hadron-Hadron Scattering Top Physics |
| DOI | 10.1007/JHEP11(2022)040 |
| 文献子类 | Article |
| 英文摘要 | A simultaneous measurement of the three components of the top-quark and top-antiquark polarisation vectors in t-channel single-top-quark production is presented. This analysis is based on data from proton-proton collisions at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 139 fb(-1), collected with the ATLAS detector at the LHC. Selected events contain exactly one isolated electron or muon, large missing transverse momentum and exactly two jets, one being b-tagged. Stringent selection requirements are applied to discriminate t-channel single-top-quark events from the background contributions. The top-quark and top-antiquark polarisation vectors are measured from the distributions of the direction cosines of the charged-lepton momentum in the top-quark rest frame. The three components of the polarisation vector for the selected top-quark event sample are P-x' = 0.01 +/- 0.18, P-y' = -0.029 +/- 0.027, P-z' = 0.91 +/- 0.10 and for the top-antiquark event sample they are P-x' = -0.02 +/- 0.20, P-y' = -0.007 +/- 0.051, P-z' = -0.79 +/- 0.16. Normalised differential cross-sections corrected to a fiducial region at the stable-particle level are presented as a function of the charged-lepton angles for top-quark and top-antiquark events inclusively and separately. These measurements are in agreement with Standard Model predictions. The angular differential cross-sections are used to derive bounds on the complex Wilson coefficient of the dimension-six O-tW operator in the framework of an effective field theory. The obtained bounds are C-tW is an element of[-0.9, 1.4] and C-itW is an element of [-0.8, 0.2], both at 95% confidence level. |
| 语种 | 英语 |
| WOS记录号 | WOS:000885306200001 |
| 源URL | [http://ir.ihep.ac.cn/handle/311005/298781]  |
| 专题 | 高能物理研究所_实验物理中心 |
| 作者单位 | 中国科学院高能物理研究所 |
| 推荐引用方式 GB/T 7714 | ATLAS Collaboration. Measurement of the polarisation of single top quarks and antiquarks produced in the t-channel at root s=13 TeV and bounds on the tWb dipole operator from the ATLAS experiment[J]. JOURNAL OF HIGH ENERGY PHYSICS,2022(11):40. |
| APA | ATLAS Collaboration.(2022).Measurement of the polarisation of single top quarks and antiquarks produced in the t-channel at root s=13 TeV and bounds on the tWb dipole operator from the ATLAS experiment.JOURNAL OF HIGH ENERGY PHYSICS(11),40. |
| MLA | ATLAS Collaboration."Measurement of the polarisation of single top quarks and antiquarks produced in the t-channel at root s=13 TeV and bounds on the tWb dipole operator from the ATLAS experiment".JOURNAL OF HIGH ENERGY PHYSICS .11(2022):40. |
入库方式： OAI收割
来源：高能物理研究所
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