Leading-order perturbative QCD calculation of nucleon Dirac form factors

The Dirac form factors $F_1^p$,n of nucleons are analyzed to leading order in the strong coupling constant ${\alpha }_s$($Q^2$) and leading twist using perturbative QCD. The effects of different choices of the nucleon distribution amplitude on the leading-twist result are explored. These results are compared with recent experimental data for the proton. We show that it is possible to fit the data for $F_1^p$ in the range 10≤$Q^2$≤30 (GeV/c${)}^2$ by evaluating the strong coupling constant ${\alpha }_s$($Q^2$) at the exact gluon kinematics for each diagram of the process within the integrals over the momentum fraction which govern the perturbative QCD prediction.