ROLE OF A NONRESONANCE BACKGROUND IN THE DIFFRACTIVE ELECTROPRODUCTION AND PHOTOPRODUCTION OF RHO(0) MESONS

The effect of a nonresonance background from diffractive photon dissoc iation into a pi(+)pi(-) pair on the elastic photoproduction of rho(0) mesons in ep interactions is discussed. The amplitude of the nonreson ance background-that is, the amplitude of the reaction gamma p --> pi( +)pi(-)p-is proportional to the total np cross section. The fitting of HERA data makes it possible to estimate the cross section sigma(pi p) at energies s(pi p) similar to (2-3) x 10(3) GeV2. The results consid erably exceed available data. At large Q(2), the interference between the resonance and nonresonance contributions to pi(+)pi(-) production results in a reduction of the ratio sigma(L)/sigma(T) with increasing pi(+)pi(-) mass.