2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/46493We extract the deep inelastic scattering cross-sections ratio $R= σ_L/σ_T$ in the range $10^{-4} \leq x \leq 10^{-1}$ from $F_2$ HERA data using very simple relations based on perturbative QCD. The result depends on only one parameter $δ$, being $x^{-δ}$ the behavior of the parton densities at low $x$, which has been determined recently with a good accuracy by the H1 group.Latex file (6 pages), 1 Postscript figureHigh Energy Physics - Phenomenologytext