Total γ*p cross section

This paper shows that the approach based on Gribov's ideas for photon-proton interaction is able to describe the experimental data over a wide range of photon virtualities Q2=0-100 GeV2 and energies √(s)=W=3-300 GeV. A simple model is suggested which provides a quantitative way of describing the matching between short and long distances (between ''soft'' and ''hard'' processes) in photon-proton interaction at high energy. The main results of our analysis are: (i) the values of the separation parameters differentiating the soft and hard interactions are determined; (ii) the additive quark model can be used to calculate the soft contribution to the photon-proton interaction; (iii) a good description of the ratio σL/σT is obtained; and (iv) a considerable contribution of the soft process at large Q2, and of hard processes at small Q2 was found (orig.)