Helicity amplitudes for single top quark production - art. no. 074025

Single top quark production at hadron colliders allows a direct measurement of the top quark charged current coupling. We present the complete tree-le vel helicity amplitudes for four processes involving the production and sem ileptonic decay of a single top quark: W-gluon fusion, flavor excitation, s -channel production and W-associated production. For the first three proces ses we study the quality of the narrow top width approximation. We also exa mine momentum and angular distributions of some of the final state particle s.