Description of deep inelastic processes in terms of the wave functions of rest-frame composite systems

The lepton-hadron inelastic scattering processes are studied in the rest frame of composite particles. A new perturbative expansion for the description of structure functions is proposed, each term of which possesses the spectral condition. It is demonstrated that, in contrast to infinite-momentum-frame case, impulse approximation is not valid for describing inelastic limit xBj → 1 in the rest frame. To obtain leading behavior of structure functions as xBj → 1 it is necessary to take account of the interaction of constituents in the final state. The corresponding diagrams are pointed out and their computation in QCD conforms with the results obtained in the O-plane quantum field theory