Decoupling of the leading contribution in the discrete BFKL Analysis of High-Precision HERA Data

We analyse, in NLO, the physical properties of the discrete eigenvalue solution for the BFKL equation. We show that a set of eigenfunctions with positive eigenvalues, \( \omega \), together with a small contribution from a continuum of eigenfunctions with negative \( \omega \), provide an excellent description of high-precision HERA \(F_2\) data in the region, \(x 6 \) \(\hbox {GeV}^2\). The phases of the eigenfunctions can be obtained from a simple parametrisation of the pomeron spectrum, which has a natural motivation within BFKL. The data analysis shows that the first eigenfunction decouples completely or almost completely from the proton. This suggests that there exists an additional ground state, which is naturally saturated and may have the properties of the soft pomeron.