# Search for single top-quark production via flavour changing neutral currents at 8 TeV with the ATLAS detector

Abstract : A search for single top-quark production via flavour changing neutral current processes from gluon plus up- or charm--quark initial states in proton--proton collisions at the LHC is presented. Data collected with the ATLAS detector in 2012 at a centre-of-mass energy of 8 TeV and corresponding to an integrated luminosity of 20.3 fb−1 are used. Candidate events for a top quark decaying into a lepton, a neutrino and a jet are selected and classified into signal- and background-like candidates using a neural network. No signal is observed and an upper limit on the production cross-section multiplied by the t→Wb branching fraction is set. The observed 95 % CL limit is σqg→t×B(t→Wb)<3.4 pb and the expected 95% CL limit is σqg→t×B(t→Wb)<2.9 pb. The observed limit can be interpreted as upper limits on the coupling constants of the flavour changing neutral current interactions divided by the scale of new physics κugt/Λ<5.8×10−3 TeV−1 and κcgt/Λ<13×10−3 TeV−1 and on the branching fractions B(t→ug)<4×10−5 and B(t→cg)<17×10−5.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-01191610
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Submitted on : Wednesday, September 2, 2015 - 11:06:50 AM
Last modification on : Friday, October 8, 2021 - 11:04:17 PM

### Citation

G. Aad, M.K. Ayoub, A. Bassalat, C. Bécot, S. Binet, et al.. Search for single top-quark production via flavour changing neutral currents at 8 TeV with the ATLAS detector. European Physical Journal C: Particles and Fields, Springer Verlag (Germany), 2016, 76, pp.55. ⟨10.1140/epjc/s10052-016-3876-4⟩. ⟨in2p3-01191610⟩

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