Search for FCNC single top-quark production at root s=7 TeV with the ATLAS detector
Üst veriTüm öğe kaydını göster
KünyeAad, G, Abbott, B., Abdallah, J., Abdelalim, A.A., Abdesselam, A., Abdinov, O. ... ATLAS Collaboration. (2012). Search for FCNC single top-quark production at root s=7 TeV with the ATLAS detector. Physics Letters B, 712 (4-5), pp. 351-369. http://dx.doi.org/10.1016/j.physletb.2012.05.022.
A search for the production of single top-quarks via flavour-changing neutral-currents is presented. Data collected with the ATLAS detector at a centre-of-mass energy of root s = 7 TeV, corresponding to an integrated luminosity of 2.05 fb(-1), are used. Candidate events with a semileptonic top-quark decay signature are classified as signal- or background-like events by using several kinematic variables as input to a neural network. No signal is observed in the neural network output distribution and a Bayesian upper limit is placed on the production cross-section. The observed upper limit at 95% confidence level on the cross-section multiplied by the t -> Wb branching fraction is measured to be sigma(qg -> t) x B(t -> Wb) < 3.9 pb. This upper limit is converted using a model-independent approach into upper limits on the coupling strengths kappa(ugt)/Lambda < 6.9.10(-3) TeV-1 and kappa(cgt)/Lambda < 1.6.10(-2) TeV-1, where A is the new physics scale, and on the branching fractions B(t -> ug) < 5.7.10(-5) and B(t -> cg) < 2.7.10(-4).