Measurement of the W boson polarisation in tt[bar] events from pp collisions at √s = 8 TeV in the lepton + jets channel with ATLAS
This paper presents a measurement of the polarisation of W bosons from tt¯ decays, reconstructed in events with one high-p T lepton and at least four jets. Data from pp collisions at the LHC were collected at s√ = 8 TeV and correspond to an integrated luminosity of 20.2 fb−1. The angle θ∗ between t...
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| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , |
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| Corporate Author: | |
| Format: | Article (Journal) |
| Language: | English |
| Published: |
26 April 2017
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| In: |
The European physical journal. C, Particles and fields
Year: 2017, Volume: 77, Issue: 4 |
| ISSN: | 1434-6052 |
| DOI: | 10.1140/epjc/s10052-017-4819-4 |
| Online Access: | Verlag, Volltext: https://doi.org/10.1140/epjc/s10052-017-4819-4 Verlag: https://link.springer.com/article/10.1140/epjc/s10052-017-4819-4 |
| Author Notes: | ATLAS Collaboration* |
| Summary: | This paper presents a measurement of the polarisation of W bosons from tt¯ decays, reconstructed in events with one high-p T lepton and at least four jets. Data from pp collisions at the LHC were collected at s√ = 8 TeV and correspond to an integrated luminosity of 20.2 fb−1. The angle θ∗ between the b-quark from the top quark decay and a direct W boson decay product in the W boson rest frame is sensitive to the W boson polarisation. Two different W decay products are used as polarisation analysers: the charged lepton and the down-type quark for the leptonically and hadronically decaying W boson, respectively. The most precise measurement of the W boson polarisation via the distribution of cosθ∗ is obtained using the leptonic analyser and events in which at least two of the jets are tagged as b-quark jets. The fitted fractions of longitudinal, left- and right-handed polarisation states are F0= 0.709 ± 0.019, FL= 0.299 ± 0.015 and FR= −0.008 ± 0.014, and are the most precisely measured W boson polarisation fractions to date. Limits on anomalous couplings of the Wtb vertex are set. |
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| Item Description: | Gesehen am 11.02.2020 Im Titel steht der Buchstabe "s" unter dem Wurzelsymbol Im Titel steht jeweils der 2. Buchstabe t mit einem Oberstrich *ATLAS Collaboration: M. Aaboud, C.F. Anders, V. Andrei, C. Antel, A.E. Baas, O. Brandt, J.J. Djuvsland, M. Dunford, D.E. Ferreira de Lima, M.P. Geisler, M. Giulini, P. Hanke, J. Jongmanns, E.-E. Kluge, M. Kolb, M. Kretz, A. Kugel, V.S. Lang, M. Lisovyi, K. Meier, H. Meyer zu Theenhausen, D.I. Narrias Villar, M. Sahinsoy, S. Schaetzel, V. Scharf, A. Schoening, H.-C. Schultz-Coulon, D. Sosa, R. Stamen, P. Starovoitov, S. Suchek, M. Wessels [und 2818 weitere Personen] |
| Physical Description: | Online Resource |
| ISSN: | 1434-6052 |
| DOI: | 10.1140/epjc/s10052-017-4819-4 |