UNSPECIFIED (2016) Search for flavour-changing neutral current top-quark decays to qZ in pp collision data collected with the ATLAS detector at √s=8 TeV. European Physical Journal C: Particles and Fields, 76 (1): 12. ISSN 1434-6044
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Abstract
A search for the flavour-changing neutral-current decay t→qZ is presented. Data collected by the ATLAS detector during 2012 from proton–proton collisions at the Large Hadron Collider at a centre-of-mass energy of s√=8 TeV, corresponding to an integrated luminosity of 20.3 fb−1, are analysed. Top-quark pair-production events with one top quark decaying through the t→qZ (q=u,c) channel and the other through the dominant Standard Model mode t→bW are considered as signal. Only the decays of the Z boson to charged leptons and leptonic W boson decays are used. No evidence for a signal is found and an observed (expected) upper limit on the t→qZ branching ratio of 7×10−4 (8×10−4) is set at the 95 % confidence level