Polarized and unpolarized structure functions in a diquark model for the nucleon

The polarized and unpolarized structure functions in deep-inelastic lepton-nucleon scattering are calculated. Restricting ourselves to inclusive scattering a model is used in which the absorption of the virtual photon by the nucleon leads to a quark-diquark final state. Differences in the mass spectrum of the possible diquark configurations are important for the calculation of the structure functions, even in the Bjorken limit. The structure functions calculated at a low-energy scale are evolved to the appropriate high-energy scale, using the Altarelli-Parisi equations. (orig.)