QCD and Yukawa corrections to single-top-quark production via q qbar ->   t bbar
  We calculate the O(alpha_s) and O(alpha_W m_t^2/M_W^2) corrections to the production of a single top quark via the weak process q qbar -> t bbar at the Fermilab Tevatron and the CERN Large Hadron Collider. An accurate calculation of the cross section is necessary in order to extract |V_tb| from experiment. 
Martin C. Smith and Scott S. Willenbrock