Possible Explanation for the Rapid Approach to "Universality" of the Inelastic Electron-Scattering Structure Functions

We have determined the single-variable analyticity of the inelastic electron-scattering structure functions in the complex $x$ plane, with $s$ kept fixed and real, to all orders of Feynman perturbation theory. We find that its Landau singularities, which move as a function of $s$, rapidly approach their asymptotic $s$-independent position once $s$ is large. We discuss how this observation offers a possible explanation for a rapid approach to "universality" of the inelastic electron-scattering structure functions and shows that $s{W}_2(s,\frac{q^2}{s})$ should "scale" faster than $\nu W_2\mathrm{}(s,x)\mathrm{}$.