TY  - SER
AU  - Abbott,B.
AU  - Abdallah,J.
AU  - Chelkov,G.A.
AU  - Aad,G.
TI  - Search for single top-quark production via flavour-changing neutral currents at 8 TeV with the ATLAS detector
KW  - ATLAS, детектор
KW  - Большой адронный коллайдер
KW  - кварки
KW  - статьи в журналах
N1  - Библиогр.: 91 назв
N2  - 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)<3.4pb and the expected 95 % CL limit is σqg→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−1 and κcgt/Λ<13×10−3TeV and on the branching fractions B(t→ug)<4.0×10−5 and B(t→cg)<20×10−5
UR  - http://vital.lib.tsu.ru/vital/access/manager/Repository/vtls:000581603
ER  -