Four point function of R-currents in N=4 SYM in the Regge limit at weak   coupling
  We compute, in N=4 super Yang-Mills theory, the four point correlation function of R-currents in the Regge limit in the leading logarithmic approximation at weak coupling. Such a correlator is the closest analog to photon-photon scattering within QCD, and there is a well-defined procedure to perform the analogous computation at strong coupling via the AdS/CFT correspondence. The main result of this paper is, on the gauge theory side, the proof of Regge factorization and the explicit computation of the R-current impact factors. 
J. Bartels, A.-M. Mischler, M. Salvadore