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

Mullier, Geoffrey; Haug, Sigve; Weber, Michael; Meloni, Federico; Cervelli, Alberto; Beck, Hans Peter; Stucci, Stefania; Ereditato, Antonio (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) EDP Sciences 10.1140/epjc/s10052-016-3876-4

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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 8TeV and corresponding to an integrated luminosity of 20.3fb⁻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 σ qg→t ×B(t→Wb)<3.4pb and the expected 95% CL limit is σ qg→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 −3 TeV −1 and κ cgt /Λ<13×10⁻³ TeV⁻¹ and on the branching fractions B(t→ug)<4×10⁻⁵ and B(t→cg)<20×10⁻⁵.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Laboratory for High Energy Physics (LHEP)

UniBE Contributor:

Haug, Sigve; Weber, Michael and Beck, Hans Peter

Subjects:

500 Science > 530 Physics
500 Science > 510 Mathematics

ISSN:

1434-6044

Publisher:

EDP Sciences

Language:

English

Submitter:

Annette Krebs-Wegenast

Date Deposited:

16 Aug 2017 12:47

Last Modified:

20 Aug 2017 02:18

Publisher DOI:

10.1140/epjc/s10052-016-3876-4

Additional Information:

Kollaboration - Es sind nur die Berner Autoren namentlich erwähnt.

BORIS DOI:

10.7892/boris.100022

URI:

https://boris.unibe.ch/id/eprint/100022

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