Deep-inelastic electron--nucleon scattering in the framework of Dashen--Gell-Mann current algebra at infinite momentum: a unified approach to resonances and partons

Deep-inelastic electron-nucleon scattering is considered within the Dashen---Gell-Mann framework of the current algebra at infinite momentum. The ensuing expression for the structure function $F_2\left(\xi \right)={lim}_{Bjorken}\nu W_2$, $\xi =-\frac{q^2}{2M_N\nu }$, contains elements of both the parton and the resonance pictures of the process. In fact, a much stronger statement is in order: Starting with what is essentially a resonance saturation scheme, we reproduce all important results of the parton model, such as the property of scaling, the characteristic representation for the $F_2\left(\xi \right)$ function, the sum rules, the asymptotic behavior of $F_2\left(\xi \right)$ for $\xi \to 0$, etc. Other topics discussed include the Drell-Yan formula, the threshold behavior of the $F_2\left(\xi \right)$ function, and the intimate relationship that exists between the mean internal distance between the nucleon constituents and the scale of momentum transfers that determines the onset of scaling.