Resolved photon and multi-component model for $γ^*$p and $γ^* γ^*$ scattering at high energies

Abstract

We generalize our previous model for $γ^* p$ scattering to $γγ$ scattering. In the latter case the number of components naturally grows. When using the model parameters from our previous $γ^* p$ analysis the model cross section for $γγ$ scattering is larger than the corresponding LEP2 experimental data by more than a factor of two. However, performing a new simultaneous fit to $γ^* p$ and $γγ$ total cross section we can find an optimal set of parameters to describe both processes. We propose new measures of factorization breaking for $γ^* γ^*$ collisions and present results for our new model.