Tunneling transition to the Pomeron regime
  We point out that, in some models of small-x hard processes, the transition to the Pomeron regime occurs through a sudden tunneling effect, rather than a slow diffusion process. We explain the basis for such a feature and we illustrate it for the BFKL equation with running coupling by gluon rapidity versus scale correlation plots. 
M. Ciafaloni, D. Colferai, G.P. Salam, A. Stasto