Resolved photon and multi-component model for ${\gamma }^{\ast }$p and ${\gamma }^{\ast }{\gamma }^{\ast }$ total cross section

Abstract

We generalize our previous model for ${\gamma }^{\ast }p$ scattering to $\gamma \gamma$ scattering. Performing a new simultaneous fit to ${\gamma }^{\ast }p$ and $\gamma \gamma$ total cross section we find an optimal set of parameters to describe both processes. We propose new measures of factorization breaking for ${\gamma }^{\ast }{\gamma }^{\ast }$ collisions and present results for our new model.

Comments: a talk at international conference PHOTON2005, Warsaw, August/September 2005