Diffractive photo- and leptoproduction
of vector mesons , and
G. Kulzinger - H.G. Dosch - H.J. Pirner
Institut für Theoretische Physik der Universität Heidelberg,
Philosophenweg 16 & 19, D-69120 Heidelberg, Germany
Received: 16 June 1998 / Published online: 22 October 1998
We calculate diffractive photo- and leptoproduction of -, - and -mesons. The incoming photon dissociates into a -dipole which scatters on the nucleon and transforms into a vector meson state. The scattering amplitude is calculated in non-perturbative QCD with the model of the stochastic vacuum. Assuming that the physical - and -mesons are mixed states of an active 2S-excitation and some residual hybrid state which cannot be produced diffractively in lowest order QCD, we obtain good agreement with the data, especially the markedly different spectrum in the -invariant mass for photoproduction and e+e--annihilation.