CGC/saturation approach: a new impact-parameter dependent model

Abstract

{In this paper we propose a new impact-parameter dependent CGC/saturation model. We introduce two new features in the model that make it consistent with what we know theoretically about the deep inelastic scattering. They are: the use of the exact form of the solution to the non-linear (BK) equation, whereas in all previous attempts only the form of $r^2Q^2_s$ dependence, has been taken into account; and the large impact parameter dependence, through the $b$-dependence of the saturation momentum which reproduce the correct behaviour of the amplitude at large impact parameters $b$ ($A \propto \exp\Lb - \mu b\Rb$) as well as at large momentum transferred $Q_T$ ($A $ decreases as a power of $Q_T$ as it follows from perturbative QCD). These improvement compared to all previous attempts to build such models, allows us to claim, that the experimental data are in accord with the prediction of CGC/saturation approach while previously, based on similar models, we could only conclude that the DIS data, perhaps, can be described by introducing the shadowing corrections at small photon virtualities.