ar X iv : h ep - p h / 96 09 35 6 v 1 1 3 Se p 19 96 The Spin - Dependent Structure Functions of Nucleons and Nuclei

We discuss connection between spin-dependent SFs of nucleons and nu-clei in the deep inelastic lepton scattering. The case of the deuteron is studied in detail in the Bethe-Salpeter formalism. In the present talk we discuss the spin-dependent structure functions (SF) of nuclei and their relation to those of nucleon. Our main focus will be the deuteron, which we study in detail in the covariant Bethe-Salpeter formalism. Why it so important and interesting to study the nuclear effects in the SFs? First, nuclei are the only source of the experimental information about neutron SFs, including the spin-dependent ones. To obtain this information, it is important to understand how nucleons are bound in the nuclei and how this binding affects their SFs. An accurate method to extract the neutron SFs from the nuclear data must be an essential part of the consistent analysis of the nu-cleon SFs. Second, a physics governing the processes with the participation of the nuclei is extremely interesting by itself. For instance, a spin-1 nucleus, such as a deuteron, has extra spin-dependent SFs than nucleons, i.e. b D 1,2. Another example , nuclei as a slightly relativistic and weakly bound systems allows for more progress than the hadrons, in studying the covariant bound state problem. In certain situations the covariant approach gives results noticeably different from the nonrelativistic ones. For the spin-dependent SFs such situation is a calculation of the b D 1,2. And third, our interest in the study of the reactions with the deuteron is in part motivated by the future and ongoing experiments. In particular, very recently we started a study of the chiral-odd SF h D 1 .