PUB - Publikationen an der Universität Bielefeld

We review the theoretical interpretation of deep-inelastic electron-proton scattering at low values of the Bjorken variable x \simeqQ2/W2 < 0.1. The process proceeds via the interaction of quark-antiquark (qq¯) color-dipole fluctuations of the (virtual) photon with the proton. In terms of the forward Compton scattering amplitude, two reaction channels contribute to the interaction of the qq¯ color dipole with the gluon field in the proton. Dependent on the kinematics, there is either color transparency, corresponding to a cancellation of the amplitudes for the two reaction channels, or saturation, occurring when the process is dominated by a single interaction channel. The connection between the color-dipole picture and the pQCD improved parton model is elaborated upon.