Valence quark distributions in nucleon at low Q2 in QCD Original Research Article

Valence u- and d-quarks distributions in proton are calculated in QCD at low Q2 and intermediate x, basing on the operator product expansion (OPE). The imaginary part of the virtual photon scattering amplitude on quark current with proton quantum numbers is considered. The initial and final virtualities p21 and p22 of the currents are assumed to be large, negative and different, p21≠p22. The OPE in p21, p22 up to dimension 6 operators was performed. Double dispersion representations in p21, p22 of the amplitudes in terms of physical states contributions are used. Putting them to be equal to those calculated in QCD, the sum rules for quark distributions are found. The double Borel transformations are applied to the sum rules. Leading order perturbative corrections are accounted. Valence quark distributions are found: u(x)v at 0.15