TY  - JOUR
AU  - ATLAS Collaboration (Aad, G. et al
AU  - Aparisi Pozo, J. A.
AU  - Bailey, A. J.
AU  - Cabrera Urban, S.
AU  - Cardillo, F.
AU  - Castillo Gimenez, V.
AU  - Costa, M. J.
AU  - Didenko, M.
AU  - Escobar, C.
AU  - Estrada Pastor, O.
AU  - Fiorini, L.
AU  - Fullana Torregrosa, E.
AU  - Fuster, J.
AU  - Garcia, C.
AU  - Garcia Navarro, J. E.
AU  - Gonzalez de la Hoz, S.
AU  - Gonzalvo Rodriguez, G. R.
AU  - Guerrero Rojas, J. G. R.
AU  - Higon-Rodriguez, E.
AU  - Lacasta, C.
AU  - Lozano Bahilo, J. J.
AU  - Mamuzic, J.
AU  - Marti-Garcia, S.
AU  - Martinez Agullo, P.
AU  - Miralles Lopez, M.
AU  - Mitsou, V. A.
AU  - Moreno Llacer, M.
AU  - Navarro-Gonzalez, J.
AU  - Poveda, J.
AU  - Prades Ibañez, A.
AU  - Ruiz-Martinez, A.
AU  - Sabatini, P.
AU  - Salt, J.
AU  - Sanchez Sebastian, V.
AU  - Sayago Galvan, I.
AU  - Soldevila, U.
AU  - Sanchez, J.
AU  - Torro Pastor, E.
AU  - Valero, A.
AU  - Valls Ferrer, J. A.
AU  - Villaplana Perez, M.
AU  - Vos, M.
PY  - 2022
DA  - 2022//
TI  - 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
T2  - J. High Energy Phys.
JO  - Journal of High Energy Physics
SP  - 040
EP  - 62pp
VL  - 11
IS  - 11
PB  - Springer
KW  - Hadron-Hadron Scattering
KW  - Top Physics
AB  - 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.
SN  - 1029-8479
UR  - https://arxiv.org/abs/2202.11382
UR  - https://doi.org/10.1007/JHEP11(2022)040
DO  - 10.1007/JHEP11(2022)040
LA  - English
N1  - WOS:000885306200001
ID  - ATLASCollaborationAad_etal2022
ER  -