Deep inelastic scattering of leptons on nuclei

Deep-inelastic scattering of charged leptons on nuclei is considered in the lowest order in electromagnetic interactions. Expressions for the corresponding differential cross-sections are obtained provided the scattered lepton and the fragment of the initial nucleus are detected in coincidence. Structure functions are analysed by means of the automodelity principle. These functions are considered in the framework of the “light front” formalism for many-body systems. A hypothesis is put forward on the scale invariance of structure functions with respect to the $\xi$-variable which is a certain complicated dimensionless combination of kinematic invariants. A simple relation of this variable to the momenta of the nucleons inside the initial nucleus is pointed out.