Direct top quark production at hadron colliders as a probe of new physics

Abstract

We examine the effect of an anomalous flavor-changing chromomagnetic moment which allows direct top quark production (two partons combining into an unaccompanied single top quark in the $s$ channel) at hadron colliders. We consider both $t\ensuremath{-}c\ensuremath{-}g$ and $t\ensuremath{-}u\ensuremath{-}g$ couplings. We find that the anomalous charm quark coupling parameter ${\ensuremath{\kappa}}_{c}/\ensuremath{\Lambda}$ can be measured down to $0.06{\mathrm{}\mathrm{TeV}}^{\ensuremath{-}1}$$(0.009{\mathrm{}\mathrm{TeV}}^{\ensuremath{-}1})$ at the Fermilab Tevatron with the Main Injector upgrade (CERN LHC). The anomalous up quark coupling parameter ${\ensuremath{\kappa}}_{u}/\ensuremath{\Lambda}$ can be measured to $0.02{\mathrm{}\mathrm{TeV}}^{\ensuremath{-}1}$$(0.003{\mathrm{}\mathrm{TeV}}^{\ensuremath{-}1})$ at the Tevatron (LHC).