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 ${\mathit{g}}_1^{\mathit{A}}$ and ${\mathit{g}}_2^{\mathit{A}}$ in terms of off-mass-shell extrapolations of polarized nucleon structure functions, ${\mathit{g}}_1^{\mathit{N}}$ and ${\mathit{g}}_2^{\mathit{N}}$. Approximate expressions for ${\mathit{g}}_{1,2}^{\mathit{A}}$ are obtained by expanding the off-shell ${\mathit{g}}_{1,2}^{\mathit{N}}$ 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.