The BFKL-Regge factorization and F 2 b , F 2 c , F L at HERA: physics implications of nodal properties of the BFKL eigenfunctions

The asymptotic freedom is known to split the leading-log 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 F (2) (c) , beauty F (2) (b) and the longitudinal structure functions of the proton at moderately large Q (2). For instance, we predicted precocious BFKL asymptotics of F (2) (c) (x, Q (2)) with intercept of the rightmost BFKL pole a (IP)(0) - 1 = Delta(IP) a parts per thousand 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 F (2) (c) and F (2) (b) we extend our 1999 predictions to the kinematical domain covered by new HERA measurements. Our parameter-free results agree well with the determination of F (2) (c) , F (L) and published H1 results F (2) (b) on but slightly overshoot the very recent (2008, preliminary) H1 results on F (2) (b) .