Spin-dependent nuclear structure functions: General approach with application to the deuteron

We study deep-inelastic scattering from polarized nuclei within a covariant framework. A clear connection is established between relativistic and nonrelativistic limits, which enables a rigorous derivation of convolution formulas for the spin-dependent nuclear structure functions g1A and g2A in terms of off-mass-shell extrapolations of polarized nucleon structure functions, g1N and g2N. Approximate expressions for g1,2A are obtained by expanding the off-shell g1,2N about their on-shell limits. As an application of the formalism we consider nuclear effects in the deuteron, knowledge of which is necessary to obtain accurate information on the spin-dependent structure functions of the neutron.