Problems with initial and final state interactions in deep inelastic scattering

Although there exists a vast literature devoted to the theory of deep inelastic scattering, the restrictions imposed on the (electromagnetic or weak) current operator by its commutation relations with the representation operators of the Poincare group have not been considered. We argue that the standard parton model results take place in the situation when the current operator does not properly commute with the representation operators of the Lorentz group. At the same time, in models with the correct commutation relations the initial and final state interactions of the struck quark with the remnants of the target cannot be neglected even in the Bjorken limit. (author). 27 refs