Impact factors for Reggeon-gluon transition in N = 4 SYM with large   number of colours
  We calculate impact factors for Reggeon-gluon transition in supersymmetric Yang-Mills theory with four supercharges at large number of colours Nc. In the next-to-leading order impact factors are not uniquely defined and must accord with BFKL kernels and energy scales. We obtain the impact factor corresponding to the kernel and the energy evolution parameter, which is invariant under Moebius transformation in momentum space, and show that it is also Moebius invariant up to terms taken into account in the BDS ansatz. 
Victor S. Fadin and Roberto Fiore
hep-th hep-ph