Probing lepton and quark substructure in polarized e∓N scattering

If leptons and quarks are composite objects their non-elementary nature would emerge clearly from deep inelastic scattering at momentum transfers of the order of the compositeness scale Λ_H. On the other hand, residual lepton-quark interactions induced by the new binding force would indicate the existence of a further layer of substructure already at considerably smaller momentum transfers. The effects of such non-standard interactions on various cross sections and asymmetries in polarized e^?N scattering are studied in detail. It is shown that, if Λ_H < 5 TeV, one should encounter rather striking deviations from the standard model expectations in the Q²-range accessible at future ep colliders like HERA.