%0 Journal Article
%T Search for flavour-changing neutral-current couplings between the top quark and the photon with the ATLAS detector at root s=13 TeV
%A ATLAS Collaboration (Aad, G. et al
%A Amos, K. R.
%A Aparisi Pozo, J. A.
%A Bailey, A. J.
%A Cabrera Urban, S.
%A Cantero, J.
%A Cardillo, F.
%A Castillo Gimenez, V.
%A Costa, M. J.
%A Didenko
%A Escobar, C.
%A Fiorini, L.
%A Fullana Torregrosa, E.
%A Fuster, J.
%A Garcia, C.
%A Garcia Navarro, J. E.
%A Gomez Delegido, A. J.
%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 Marti-Garcia, S.
%A Martinez Agullo, P.
%A Miralles Lopez, M.
%A Mitsou, V. A.
%A Monsonis Romero, L.
%A Moreno Llacer, M.
%A Munoz Perez, D.
%A Navarro-Gonzalez, J.
%A Poveda, J.
%A Prades Ibañez, A.
%A Rubio Jimenez, A.
%A Ruiz-Martinez, A.
%A Sabatini, P.
%A Salt, J.
%A Sanchez Sebastian, V.
%A Sayago Galvan, I.
%A Senthilkumar, V.
%A Soldevila, U.
%A Sanchez, J.
%A Torro Pastor, E.
%A Valero, A.
%A Valls Ferrer, J. A.
%A Varriale, L.
%A Villaplana Perez, M.
%A Vos, M.
%J Physics Letters B
%D 2023
%V 842
%I Elsevier
%@ 0370-2693
%G English
%F ATLASCollaborationAad_etal2023
%O WOS:001023760300001
%O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=5634), last updated on Fri, 15 Sep 2023 12:51:15 +0000
%X This letter documents a search for flavour-changing neutral currents (FCNCs), which are strongly sup-pressed in the Standard Model, in events with a photon and a top quark with the ATLAS detector. The analysis uses data collected in pp collisions at & RADIC;s =13 TeV during Run 2 of the LHC, corresponding to an integrated luminosity of 139 fb-1. Both FCNC top-quark production and decay are considered. The final state consists of a charged lepton, missing transverse momentum, a b-tagged jet, one high-momentum photon and possibly additional jets. A multiclass deep neural network is used to classify events either as signal in one of the two categories, FCNC production or decay, or as background. No significant ex-cess of events over the background prediction is observed and 95% CL upper limits are placed on the strength of left-and right-handed FCNC interactions. The 95% CL bounds on the branching fractions for the FCNC top-quark decays, estimated (expected) from both top-quark production and decay, are B(t & RARR; u & gamma; ) < 0.85 (0.88+0.37 -0.25) x 10-5 and B(t & RARR; c & gamma; ) < 4.2 (3.40+1.35-0.95) x 10-5 for a left-handed tq & gamma; cou-pling, and B(t & RARR; u & gamma; ) < 1.2 (1.20+0.50 -0.33) x10-5 and B(t & RARR; c & gamma; ) < 4.5 (3.70+1.47 -1.03) x10-5 for a right-handed coupling.
%R 10.1016/j.physletb.2022.137379
%U https://arxiv.org/abs/2205.02537
%U https://doi.org/10.1016/j.physletb.2022.137379
%P 137379-22pp