Speaker
Ozan Arslan
(Universitaet Bonn (DE))
Description
A search for anomalous single top-quark production via strong
avour chang-
ing neutral currents has been performed. Data collected by the ATLAS exper-
iment in 2012 at a centre-of-mass energy
$\sqrt s$ = 8 TeV, and corresponding to
an integrated luminosity of 20.3 $fb^{-1}$ are used. Events in which a light quark
(u or c) interacts with a gluon to produce a single top quark are sought. To
discriminate between signal and background processes a multivariate technique
using a neural network is applied. The nal statistical analysis was performed
using a frequentist technique. As no signal is seen in the observed output distri-
bution, an upper limit on the production cross-section is set. The observed 95%
CL limit on the production cross-section multiplied by the $t \rightarrow bW$ branching
fraction $\sigma_{qg\rightarrow t} \times B(t \rightarrow bW)$ is measured. From this, the upper limit on the
coupling constants $\kappa_{ugt}/\Lambda$ and $\kappa_{cgt}/\Lambda$ and on the branching fractions $B(t \rightarrow ug)$
and $B(t \rightarrow cg)$ are derived.
Author
Judith Katzy
(DESY, HAMBURG)
