Soft QCD dynamics of elastic scattering in the impact parameter representation - art. no. 054001

The elastic hadronic amplitude is calculated using the nonperturbative ligh t-cone dipole representation for gluon bremsstrahlung. The data for large m ass diffraction demand a two-scale structure of light hadrons: gluon clouds of valence quarks with size similar to0.3 fm and hadronic size similar to1 fm. The presence of the two scales unavoidably leads to a specific form fo r the total hadronic cross section which consists of a steeply rising propo rtional to s(Delta) (Delta = 0.17+/-0.01) term related to gluon radiation a nd a large constant term originating from soft interactions which does not induce any gluon emission. Our calculations reproduce well the total cross sections and elastic slopes. To further test the model, we analyze the elas tic pp and (p) over barp differential cross sections and extract the partia l amplitudes in the impact parameter representation. The Pomeron trajectory as a function of the impact parameter is only slightly above 1 for central collisions, but steeply grows towards the periphery. The model predicts co rrectly the shape and energy dependence of the partial amplitude at all imp act parameters.