Next-to-Leading-Order QCD Predictions for the Nucleon Form Factors

Abstract

We accomplish for the first time the next-to-leading-order QCD computations of the leading-twist contributions to the Dirac form factors of both the proton and the neutron by applying the hard-collinear factorization theorem rigorously. The resulting predictions for these baryon form factors indicate that the one-loop perturbative corrections to the hard-gluon-exchange contributions are numerically substantial for a wide range of momentum transfers accessible in the current and forthcoming collider experiments. Including further the (formally) power-suppressed soft contributions due to the celebrated Feynman mechanism, we then perform the state-of-the-art analysis of the Dirac electromagnetic nucleon form factors from first field-theoretical principles, thus allowing for the most robust determinations of the nucleon distribution amplitudes from the direct comparison with the experimental measurements.