Direct-Channel Resonance Model of Deep-Inelastic Electron Scattering. I. Scattering on Unpolarized Targets

Abstract

We construct a resonance model of deep-inelastic electron scattering. Using semiempirical rules for the form of the nucleon spectrum and a universality hypothesis for the transition form factors, we obtain explicit expressions for the structure functions ${W}_{1}$ and ${W}_{2}$ in the Bjorken limit. The ratio of the longitudinal to transverse photoabsorption cross sections vanishes for large momentum transfers, and $\ensuremath{\nu}{W}_{2}$ becomes scale invariant. A one-parameter fit is obtained to $\ensuremath{\nu}{W}_{2}$ (proton), and a zero-parameter prediction is made of $\ensuremath{\nu}{W}_{2}$ (proton)-$\ensuremath{\nu}{W}_{2}$ (neutron). There is good agreement between the theory and experiment in the region where scale invariance is well established.