%0 Journal Article
%T Search for flavour-changing neutral currents in processes with one top quark and a photon using 81 fb(-1) of pp collisions at root s=13 TeV with the ATLAS experiment
%A ATLAS Collaboration (Aad, G. et al
%A Alvarez Piqueras, D.
%A Aparisi Pozo, J. A.
%A Bailey, A. J.
%A Cabrera Urban, S.
%A Castillo, F. L.
%A Castillo Gimenez, V.
%A Cerda Alberich, L.
%A Costa, M. J.
%A Escobar, C.
%A Estrada Pastor, O.
%A Ferrer, A.
%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.
%A Higon-Rodriguez, E.
%A Lacasta, C.
%A Lozano Bahilo, J. J.
%A Madaffari, D.
%A Mamuzic, J.
%A Marti-Garcia, S.
%A Melini, D.
%A Miñano, M.
%A Mitsou, V. A.
%A Rodriguez Bosca, S.
%A Rodriguez Rodriguez, D.
%A Ruiz-Martinez, A.
%A Salt, J.
%A Santra, A.
%A Soldevila, U.
%A Sanchez, J.
%A Valero, A.
%A Valls Ferrer, J. A.
%A Vos, M.
%J Physics Letters B
%D 2020
%V 800
%I Elsevier
%@ 0370-2693
%G English
%F ATLASCollaborationAad_etal2020
%O WOS:000503832500051
%O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=4242), last updated on Mon, 20 Jan 2020 07:54:10 +0000
%X A search for flavour-changing neutral current (FCNC) events via the coupling of a top quark, a photon, and an up or charm quark is presented using 81 fb(-1) of proton-proton collision data taken at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. Events with a photon, an electron or muon, a b-tagged jet, and missing transverse momentum are selected. A neural network based on kinematic variables differentiates between events from signal and background processes. The data are consistent with the background-only hypothesis, and limits are set on the strength of the tq gamma coupling in an effective field theory. These are also interpreted as 95% CL upper limits on the cross section for FCNC t gamma production via a left-handed (right-handed) tu gamma coupling of 36 fb (78 fb) and on the branching ratio for t -> gamma u of 2.8 x 10(-5) (6.1 x 10(-5)). In addition, they are interpreted as 95% CL upper limits on the cross section for FCNC t gamma production via a left-handed (right-handed) tc.coupling of 40 fb (33 fb) and on the branching ratio for t -> gamma c of 22 x 10(-5) (18 x 10(-5)).
%R 10.1016/j.physletb.2019.135082
%U https://arxiv.org/abs/1908.08461
%U https://doi.org/10.1016/j.physletb.2019.135082
%P 135082-21pp