Different Aspects of BFKL at NLL

Abstract

Progress in the understanding of the BFKL approach in the NLL approximation is reported. The study based on the iteration of the kernel using the exponentiation of the gluon Regge trajectory is reviewed in QCD and N=4 super Yang-Mills theories. Properties of the gluon Green's function in the high energy Regge limit for forward and non-forward scattering are considered. A novel representation of collinearly improved kernels is also presented.