2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/186975Two-jet production from the direct photon contribution at HERA is a sensitive measure of the small-$x$ gluon in the proton. We propose measurements of ratios of the jet cross-sections which will clearly distinguish between gluons with or without singular behaviour at small $x$. Furthermore, we show that analogous ratio measurements for the resolved photon contribution provide a sensitive way of determining the gluon distribution in the photon.Rutherford Appleton Laboratory report RAL-93-071 7 pages 3 figs Fig2 and Fig3 included as psfilesHigh Energy Physics - Phenomenologytext