%0 Journal Article
%T 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
%A ATLAS Collaboration (Aad, G. et al
%A Aparisi Pozo, J. A.
%A Bailey, A. J.
%A Cabrera Urban, S.
%A Cardillo, F.
%A Castillo Gimenez, V.
%A Costa, M. J.
%A Didenko, M.
%A Escobar, C.
%A Estrada Pastor, O.
%A Fiorini, L.
%A Fullana Torregrosa, E.
%A Fuster, J.
%A Garcia, C.
%A Garcia Navarro, J. E.
%A Gonzalez de la Hoz, S.
%A Gonzalvo Rodriguez, G. R.
%A Guerrero Rojas, J. G. R.
%A Higon-Rodriguez, E.
%A Lacasta, C.
%A Lozano Bahilo, J. J.
%A Mamuzic, J.
%A Marti-Garcia, S.
%A Martinez Agullo, P.
%A Miralles Lopez, M.
%A Mitsou, V. A.
%A Moreno Llacer, M.
%A Navarro-Gonzalez, J.
%A Poveda, J.
%A Prades Ibañez, A.
%A Ruiz-Martinez, A.
%A Sabatini, P.
%A Salt, J.
%A Sanchez Sebastian, V.
%A Sayago Galvan, I.
%A Soldevila, U.
%A Sanchez, J.
%A Torro Pastor, E.
%A Valero, A.
%A Valls Ferrer, J. A.
%A Villaplana Perez, M.
%A Vos, M.
%J Journal of High Energy Physics
%D 2022
%V 11
%N 11
%I Springer
%@ 1029-8479
%G English
%F ATLASCollaborationAad_etal2022
%O WOS:000885306200001
%O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=5419), last updated on Mon, 05 Dec 2022 07:45:30 +0000
%X 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.
%K Hadron-Hadron Scattering
%K Top Physics
%R 10.1007/JHEP11(2022)040
%U https://arxiv.org/abs/2202.11382
%U https://doi.org/10.1007/JHEP11(2022)040
%P 040-62pp