The BFKL-Regge factorization and F₂ᵇ, F₂ᶜ, Fₗ at HERA: physics implications of nodal properties of the BFKL eigenfunctions

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The asymptotic freedom is known to split the leading- BFKL pomeron into a series of isolated poles in the complex angular momentum plane. One of our earlier findings was that the subleading hard BFKL exchanges decouple from such experimentally important observables as small-x charm, F₂ᶜ, and the longitudinal, Fₗ, structure functions of the proton at moderately large Q². For instance, we predicted precocious BFKL asymptotics of F₂ᶜ(x,Q²) with intercept of the rightmost BFKL pole α(0)-1=Δ≈ 0.4. On the other hand, the small-x open beauty photo- and electro-production probes the vacuum exchange for much smaller color dipoles which entails significant subleading vacuum pole corrections to the small-x behavior. In view of the accumulation of the experimental data on small-x F₂ᶜ, F₂ᵇ and Fₗ we extend our early predictions to the kinematical domain covered by new HERA measurements. Our parameter-free results agree well with the determination of F₂ᶜ, Fₗ and published H1 results on F₂ᵇ but slightly overshoot the very recent (2008, preliminary) H1 results on F₂ᵇ.