In this paper, we show how the Drell-Hearn-Gerasimov (DHG) sum rule in the real photon limit can be generalized to electroproduction, and related to the sum rules in deep inelastic scattering. A general ${\mathit{Q}}^2$ dependence for the polarized function is discussed, particularly in the resonance region. The resonance ${\mathit{P}}_{33}$(1232) plays a very important role in the resonance region; in particular, it saturates the DHG sum rule for neutrons in the SU(6)⊗O(3) basis. We show that the information from the polarized structure function in the low-${\mathit{Q}}^2$ region where the baryon resonances play a dominant role provides a very important probe of the spin-flavor structure of the nucleon.

• Received 3 September 1992

DOI:https://doi.org/10.1103/PhysRevD.47.1854