Balitskiǐ-Fadin-Kuraev-Lipatov equation versus data from DESY HERA

The BFKL equation and the ${\mathit{k}}_{\mathit{T}}$-factorization theorem are used to obtain predictions for ${\mathit{F}}_2$ in the small Bjo/rken-x region over a wide range of ${\mathit{Q}}^2$. The dependence on the parameters, especially on those concerning the infrared region, is discussed. After a background fit to recent experimental data obtained at DESY HERA and at Fermilab (E665 experiment) we find that the predicted, almost ${\mathit{Q}}^2$ independent BFKL slope λ≳0.5 appears to be too steep at lower ${\mathit{Q}}^2$ values. Thus there seems to be a chance that future HERA data can distinguish between pure BFKL and conventional field theoretic renormalization group approaches. © 1995 The American Physical Society.