%0 Journal Article
%T Search for flavour-changing neutral current top-quark decays t -> qZ in proton-proton collisions at root s=13 TeV with the ATLAS detector
%A ATLAS Collaboration (Aaboud, M. et al
%A Alvarez Piqueras, D.
%A Barranco Navarro, L.
%A Cabrera Urban, S.
%A Castillo Gimenez, V.
%A Cerda Alberich, L.
%A Costa, M. J.
%A Escobar, C.
%A Estrada Pastor, O.
%A Fernandez Martinez, P.
%A Ferrer, A.
%A Fiorini, L.
%A Fuster, J.
%A Garcia, C.
%A Garcia Navarro, J. E.
%A Gonzalez de la Hoz, S.
%A Higon-Rodriguez, E.
%A Jimenez Pena, J.
%A Lacasta, C.
%A Madaffari, D.
%A Mamuzic, J.
%A Marti-Garcia, S.
%A Melini, D.
%A Mitsou, V. A.
%A Pedraza Lopez, S.
%A Rodriguez Bosca, S.
%A Rodriguez Rodriguez, D.
%A Romero Adam, E.
%A Salt, J.
%A Soldevila, U.
%A Sanchez, J.
%A Valero, A.
%A Valls Ferrer, J. A.
%A Vos, M.
%J Journal of High Energy Physics
%D 2018
%V 07
%N 7
%I Springer
%@ 1029-8479
%G English
%F ATLASCollaborationAaboud_etal2018
%O WOS:000443814800001
%O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=3727), last updated on Sat, 22 Sep 2018 11:58:50 +0000
%X A search for flavour-changing neutral-current processes in top-quark decays is presented. Data collected with the ATLAS detector from proton-proton collisions at the Large Hadron Collider at a centre-of-mass energy of root s = 13TeV, corresponding to an integrated luminosity of 36.1 fb(-1), are analysed. The search is performed using top-quark pair events, with one top quark decaying through the t -> qZ (q = u, c) flavour-changing neutral-current channel, and the other through the dominant Standard Model mode t -> bW. Only Z boson decays into charged leptons and leptonic W boson decays are considered as signal. Consequently, the final-state topology is characterized by the presence of three isolated charged leptons (electrons or muons), at least two jets, one of the jets originating from a b-quark, and missing transverse momentum from the undetected neutrino. The data are consistent with Standard Model background contributions, and at 95% confidence level the search sets observed (expected) upper limits of 1.7 x 10(-4) (2.4 x 10(-4)) on the t -> uZ branching ratio and 2.4 x 10(-4) (3.2 x 10(-4)) on the t -> cZ branching ratio, constituting the most stringent limits to date.
%K Hadron-Hadron scattering (experiments)
%R 10.1007/JHEP07(2018)176
%U http://arxiv.org/abs/1803.09923
%U https://doi.org/10.1007/JHEP07(2018)176
%P 176-41pp