Search for Production of Single Top Quarks Via tcg and tug Flavor Changing-Neutral-Current Couplings

V. M. Abazov, Joint Institute for Nuclear Research, Dubna, Russia
Kenneth A. Bloom, University of Nebraska - Lincoln
Gregory Snow
D0 Collaboration

Document Type Article

Published by American Physical Society. Phys. Rev. Lett. 99, 191802 (2007). http://prl.aps.org. Copyright © 2007 American Physical Society. Permission to use.

Abstract

We search for the production of single top quarks via flavor-changing-neutral-current couplings of a gluon to the top quark and a charm (c) or up (u) quark. We analyze 230 pb^-1 of lepton + jets data from pp̅ collisions at a center of mass energy of 1.96 TeV collected by the D0 detector at the Fermilab Tevatron Collider. We observe no significant deviation from standard model predictions, and hence set upper limits on the anomalous coupling parameters K_g^c/ Λ and K_g^u/ Λ, where K_g define the strength of tcg and tug couplings, and Λ defines the scale of new physics. The limits at 95% C.L. areK_g^c/ Λ < 0.15 TeV^-1 and K_g^u/ Λ < 0.037 TeV^-1.