Measurement of the polarisation of single top quarks and antiquarks produced in the t-channel at s = 13 TeV and bounds on the tWb dipole operator from the ATLAS experiment
In: Journal of High Energy Physics, Jg. 2022 (2022), Heft 11
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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 Px′ = 0.01 ± 0.18, Py′ = −0.029 ± 0.027, Pz′ = 0.91 ± 0.10 and for the top-antiquark event sample they are Px′ = −0.02 ± 0.20, Py′ = −0.007 ± 0.051, Pz′ = 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 OtW operator in the framework of an effective field theory. The obtained bounds are CtW ∈ [−0.9, 1.4] and CitW ∈ [−0.8, 0.2], both at 95% confidence level. [Figure not available: see fulltext.].
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Measurement of the polarisation of single top quarks and antiquarks produced in the t-channel at s = 13 TeV and bounds on the tWb dipole operator from the ATLAS experiment
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Autor/in / Beteiligte Person: | Aad, G ; Abbott, B ; Abbott, DC ; Abed Abud, A ; Abeling, K ; Abhayasinghe, DK ; Abidi, SH ; Abramowicz, H ; Abreu, H ; Abulaiti, Y ; Abusleme Hoffman, AC ; Acharya, BS ; Achkar, B ; Adam, L ; Adam Bourdarios, C ; Adamczyk, L ; Adamek, L ; Addepalli, SV ; Adelman, J ; Adiguzel, A ; Adorni, S ; Adye, T ; Affolder, AA ; Afik, Y ; Agapopoulou, C ; Agaras, MN ; Agarwala, J ; Aggarwal, A ; Agheorghiesei, C ; Aguilar-Saavedra, JA ; Ahmad, A ; Ahmadov, F ; Ahmed, WS ; Ai, X ; Aielli, G ; Aizenberg, I ; Akatsuka, S ; Akbiyik, M ; Åkesson, TPA ; Akimov, AV ; Al Khoury, K ; Alberghi, GL ; Albert, J ; Albicocco, P ; Alconada Verzini, MJ ; Alderweireldt, S ; Aleksa, M ; Aleksandrov, IN ; Alexa, C ; Alexopoulos, T ; Alfonsi, A ; Alfonsi, F ; Alhroob, M ; Ali, B ; Ali, S ; Aliev, M ; Alimonti, G ; Allaire, C ; Allbrooke, BMM ; Allport, PP ; Aloisio, A ; Alonso, F ; Alpigiani, C ; Alunno Camelia, E ; Alvarez Estevez, M ; Alviggi, MG ; Amaral Coutinho, Y ; Ambler, A ; Ambroz, L ; Amelung, C ; Amidei, D ; Amor Dos Santos, SP ; Amoroso, S ; Amrouche, CS ; Anastopoulos, C ; Andari, N ; Andeen, T ; Anders, JK ; Andrean, SY ; Andreazza, A ; Angelidakis, S ; Angerami, A ; Anisenkov, AV ; Annovi, A ; Antel, C ; Anthony, MT ; Antipov, E ; Antonelli, M ; Antrim, DJA ; Anulli, F ; Aoki, M ; Aparisi Pozo, JA ; Aparo, MA ; Aperio Bella, L ; Aranzabal, N ; Araujo Ferraz, V ; Arcangeletti, C ; Arce, ATH ; Arena, E ; Arguin, J-F |
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Zeitschrift: | Journal of High Energy Physics, Jg. 2022 (2022), Heft 11 |
Veröffentlichung: | eScholarship, University of California, 2022 |
Medientyp: | academicJournal |
Umfang: | 40 |
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