Deep inelastic scattering and 'elastic' diffraction

We examine the total cross section of virtual photons on protons, σγ*p(W2,Q2), at low x congruent with Q2/W2<<1 and its connection with 'elastic' diffractive production γT,L*p→XT,LJ=1p in the two-gluon exchange dynamics for the virtual forward Compton scattering amplitude. Solely based on the generic structure of two-gluon exchange, we establish that the cross section is described by the (imaginary part of the) amplitude for forward scattering of qq-bar vector states, (qq-barT,LJ=1p→(qq-bar)T,LJ=1p. The generalized vector dominance picture is accordingly established to only rest on the two-gluon-exchange generic structure. This is explicitly seen by the sum rules that allow one to directly relate the total cross section to the cross section for elastic diffractive forward production, γT,L*p→(qq-bar)T,LJ=1p, of vector states