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

, The ATLAS collaboration (2016) 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, 76 (2). ISSN 1434-6044

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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−1−1 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→Wbt→Wb branching fraction is set. The observed 95 % CL limit is σqg→t×B(t→Wb)<3.4pbσqg→t×B(t→Wb)<3.4pb and the expected 95 % CL limit is σqg→t×B(t→Wb)<2.9pbσqg→t×B(t→Wb)<2.9pb. 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<5.8×10−3TeV−1κugt/Λ<5.8×10−3TeV−1 and κcgt/Λ<13×10−3TeVκcgt/Λ<13×10−3TeV and on the branching fractions B(t→ug)<4.0×10−5B(t→ug)<4.0×10−5and B(t→cg)<20×10−5B(t→cg)<20×10−5.

Item Type:
Journal Article
Journal or Publication Title:
European Physical Journal C: Particles and Fields
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/2200/2201
Subjects:
ID Code:
79631
Deposited By:
Deposited On:
18 May 2016 10:10
Refereed?:
Yes
Published?:
Published
Last Modified:
26 Nov 2020 03:55