The resummed quark form factor in dimensional regularization
  The resummed expression for the quark form factor illustrates the fact that dimensional continuation provides a regularization not only for ultraviolet and infrared singularities of fixed order QCD amplitudes, but also for the Landau pole arising in resummed calculations. Explicit renormalization group invariant analytic expressions for the logarithm of the form factor are given up to two-loop order in the QCD beta function. 
Lorenzo Magnea