  The leading-order perturbative QCD (pQCD) predictions to nucleon
electromagnetic form factors were first made in late 70s. Nearly half a century
later, we accomplish the calculation of the next-to-leading-order (NLO) QCD
corrections to proton and neutron's Dirac form factors at large momentum
transfer, to the leading-twist accuracy in collinear factorization. The effect
of NLO perturbative corrections turns out to be positive and substantial.
Confronting our state-of-the-art pQCD predictions with the available data for
nucleon Dirac form factors, in both space-like and time-like regions, imposes a
stringent test on the validity of the parameterized forms of nucleon
leading-twist light-cone-distribution amplitudes (LCDAs), which have been
predicted by a class of QCD sum rules-based models and lattice QCD simulation.
