Search for top-quark production via flavor-changing neutral currents in W+1 jet events at CDF

Understand

We report on the first search for top-quark production via flavor-changing neutral-current (FCNC) interactions in the non-standard-model process u(c)+g -> t using ppbar collision data collected by the CDF II detector.

• The data set corresponds to an integrated luminosity of 2.2/fb.
• The candidate events feature the signature of semileptonic top-quark decays and are classified as signal-like or background-like by an artificial neural network trained on simulated events.
• The observed discriminant distribution is in good agreement with the one predicted by the standard model and provides no evidence for FCNC top-quark production, resulting in a Bayesian upper limit on the production cross section sigma (u(c)+g -> t) < 1.8 pb at the 95% confidence level.