Single-top-quark production via [Formula presented]-gluon fusion at next-to-leading order

Single-top-quark production via [Formula presented]-gluon fusion at hadron colliders provides an opportunity to directly probe the charged-current interaction of the top quark. We calculate the next-to-leading-order corrections to this process at the Fermilab Tevatron, the CERN Large Hadron Collider, and DESY HERA. Using a [Formula presented]-quark distribution function to sum collinear logarithms, we show that there are two independent corrections, of order [Formula presented] and [Formula presented] This observation is generic to processes involving a perturbatively derived heavy-quark distribution function at an energy scale large compared with the heavy-quark mass.