Probing QCD dynamics in two-photon interactions at high energies
  In this paper the two-photon interactions at high energies are investigated considering different approaches for the QCD dynamics. In particular, we calculate the $\gamma^* \gamma^*$ total cross section in different theoretical approches and present a comparison among the predictions of the BFKL dynamics at leading and next-to-leading order with those from saturation physics. We analyze the possibility that the future linear colliders could discriminate between these different approaches. 
V.P. Goncalves, M.V.T. Machado, W. K. Sauter