Unitarity constraints and role of geometrical effects in deep-inelastic scattering and vector meson electroproduction

Deep-inelastic scattering at low x and elastic vector meson electroproduction are analyzed on the basis of the s-channel unitarity extended to off-shell particle scattering. It appeared that the role of unitarity is important, but contrary to the case of on-shell scattering it does not rule out a power-like behavior of the total cross sections. We discuss the behavior of the total cross section of virtual photon–proton scattering in the geometrical approach and obtain the result that the exponent of the power-like energy dependence of is related to the constituent quark interaction radius. The mass effects and energy dependence of vector meson electroproduction are discussed along with the angular distributions at large momentum transfers in these processes. Received: 10 September 2001 / Published online: 7 December 2001