Nucleon distribution amplitudes and their application to nucleon form factors and the N→Δ transition at intermediate values of Q2.

Abstract

We compare a recent lattice determination of the nucleon distribution amplitudes with other approaches and models. We study the nucleon distribution amplitudes up to twist 6 in next-to-leading conformal spin and we also investigate conformal d-wave contributions to the leading-twist distribution amplitude. With the help of light-cone sum rules one can relate the distribution amplitudes to the form factors of the nucleon or the N→Δ transition at intermediate values of the momentum transfer. We compare our results with experimental data in the range 1  GeV2≤Q2≤10  GeV2. Keeping in mind that we are working only in leading order QCD and next-to-leading order QCD corrections might be sizeable, we already obtain a surprisingly good agreement for the nucleon form factors GnM, GpM, GpA, and GpT and for the N→Δ transition form factor ratios REM and RSM.