FIZIKA B 8 (1999) 2, 375-382
VECTOR MESONS r r' AND r"
DIFFRACTIVELY PHOTO- AND LEPTOPRODUCED
Institut für Theoretische Physik der Universität Heidelberg,
Philosophenweg 16, 69120 Heidelberg, Germany
Received 14 January 1999; Accepted 12 July 1999
In the framework of non-perturbative QCD, we calculate high-energy diffractive
production of vector mesons r r' and r"
by real and virtual photons on a nucleon. The initial photon dissociates into a qq
-dipole and transforms into a vector meson by scattering off the nucleon which, for
simplicity, is represented as quark-diquark. The relevant dipole-dipole scattering
amplitude is provided by the non-perturbative model of the stochastic QCD vacuum. The wave
functions result from considerations in the frame of light-front dynamics; the physical r r' and r"-mesons are assumed to be
mixed states of an active 2S-excitation and some residual rest (2D- and/or hybrid state).
We obtain good agreement with the experimental data and get an understanding of the
markedly different p+p--mass
spectra for photoproduction and e+e--annihilation.
PACS numbers: 12.38.-t, 13.60.Le
Keywords: non-perturbative QCD, diffraction, photoproduction, photon wave function, r-meson, excited vector mesons, hybrid