Improving QCD Perturbative Predictions and Transverse Momentum Effects
  I elaborate on the implementation of analyticity of hadronic quantities at the amplitude level and show that it amounts to the extension of Analytic Perturbation Theory of Shirkov and Solovtsov to non-integer (fractional) powers of the strong running coupling. I give evidence that at the NLO of the factorized pion's electromagnetic form factor this framework diminishes the uncertainty due to the renormalization-scheme choice and nearly removes the dependence on both the renormalization and the factorization scale. I supplement this discussion by considering effects caused by retaining transverse momenta that give rise to Sudakov factors. 
N.G. Stefanis