Gluon bremsstrahlung and hadron-proton cross section

The differential and the total cross sections in high energy hadron-proton interactions give a beautiful insight in the low Q(2) structure of the nucleon. The cross section is composed of two parts: a large energy independent part corresponding to the interaction of the valence quark with the target without gluon radiation and an energy dependent part caused by gluon bremsstrahlung. The gluons are located at small transverse distances of about 0.3 fm from the valence quarks. The model with two scales, the size of the hadron (R-2 approximate to 1 fm(2)) and the size of the gluonic cloud (r(0)(2) approximate to 0.1 fm(2)), correctly predicts the total and the differential cross sections and the behaviour of diffractive dissociation in hadronic and deep inelastic events