IMPLICATIONS OF SCALING VIOLATIONS OF F2 AT HERA FOR PERTURBATIVE QCD

We critically examine the QCD predictions for the Q2 dependence of the electron-proton deep-inelastic structure function F2 (x, Q2) in the s mall x region, which is being probed at HERA. The standard results bas ed on next-to-leading order Altarelli-Parisi evolution are compared wi th those that follow from the BFKL equation, which corresponds to the resummation of the leading log(1/x) terms. The effects of parton scree ning are also quantified. The theoretical predictions are confronted w ith each other, and with existing data from HERA.