TY - JOUR AU - ATLAS Collaboration (Aad, G. et al AU - Amos, K. R. AU - Aparisi Pozo, J. A. AU - Bailey, A. J. AU - Bouchhar, N. AU - Cabrera Urban, S. AU - Cantero, J. AU - Cardillo, F. AU - Castillo Gimenez, V. AU - Chitishvili, M. AU - Costa, M. J. AU - Didenko AU - Escobar, C. AU - Fiorini, L. AU - Fullana Torregrosa, E. AU - Fuster, J. AU - Garcia, C. AU - Garcia Navarro, J. E. AU - Gomez Delegido, A. J. 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 - Marti-Garcia, S. AU - Martinez Agullo, P. AU - Miralles Lopez, M. AU - Mitsou, V. A. AU - Monsonis Romero, L. AU - Moreno Llacer, M. AU - Munoz Perez, D. AU - Navarro-Gonzalez, J. AU - Poveda, J. AU - Prades Ibañez, A. AU - Rubio Jimenez, A. AU - Ruiz-Martinez, A. AU - Sabatini, P. AU - Salt, J. AU - Sanchez Sebastian, V. AU - Sayago Galvan, I. AU - Senthilkumar, V. AU - Soldevila, U. AU - Sanchez, J. AU - Torro Pastor, E. AU - Valero, A. AU - Valls Ferrer, J. A. AU - Varriale, L. AU - Villaplana Perez, M. AU - Vos, M. PY - 2023 DA - 2023// TI - Measurement of the polarisation of W bosons produced in top-quark decays using dilepton events at √s=13TeV with the ATLAS experiment T2 - Phys. Lett. B JO - Physics Letters B SP - 137829 EP - 22pp VL - 843 PB - Elsevier AB - A measurement of the polarisation of Wbosons produced in top-quark decays is presented, using proton-proton collision data at a centre-of-mass energy of v s= 13TeV. The data were collected by the ATLAS detector at the Large Hadron Collider and correspond to an integrated luminosity of 139fb(-1). The measurement is performed selecting t tevents decaying into final states with two charged leptons (electrons or muons) and at least two b-tagged jets. The polarisation is extracted from the differential cross-section distribution of the cos theta* variable, where theta(*) is the angle between the momentum direction of the charged lepton from the Wboson decay and the reversed momentum direction of the b-quark from the top-quark decay, both calculated in the Wboson rest frame. Parton-level results, corrected for the detector acceptance and resolution, are presented for the cos theta* angle. The measured fractions of longitudinal, left- and right-handed polarisation states are found to be f(0) = 0.684 +/- 0.005 (stat.)+/- 0.014 (syst.), f(L)= 0.318 +/- 0.003 (stat.)+/- 0.008 (syst.) and f(R)=-0.002 +/- 0.002 (stat.)+/- 0.014 (syst.), in agreement with the Standard Model prediction. SN - 0370-2693 UR - https://arxiv.org/abs/2209.14903 UR - https://doi.org/10.1016/j.physletb.2023.137829 DO - 10.1016/j.physletb.2023.137829 LA - English N1 - WOS:001057197500001 ID - ATLASCollaborationAad_etal2023 ER -