Search for single top-quark production via flavour-changing neutral currents at 8 TeV with the ATLAS detector
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 in...
Guardado en:
| Autores principales: | , , , , , , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
| Publicado: |
2016
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| Materias: | |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/87008 |
| Aporte de: |
| Sumario: | 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<sup>-1</sup> 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 σ<sub>qg→t</sub> × B(t → Wb) < 3.4 pb and the expected 95 % CL limit is σ<sub>qg→t</sub> × 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 κ<sub>ugt</sub> /Λ < 5.8 × 10<sup>-3</sup> TeV<sup>-1</sup> and κ<sub>cgt</sub> /Λ < 13×10<sup>-3</sup> TeV and on the branching fractions B(t → ug) < 4.0 × 10<sup>-5</sup> and B(t → cg) < 20 × 10<sup>-5</sup>. |
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