2021 Impact factor 4.991
Particles and Fields
Eur. Phys. J. C 7, 73-86
DOI 10.1007/s100529800986

Diffractive photo- and leptoproduction
of vector mesons $\rho$, $\rho'$ and $\rho''$

G. Kulzinger - H.G. Dosch - H.J. Pirner

Institut für Theoretische Physik der Universität Heidelberg, Philosophenweg 16 & 19, D-69120 Heidelberg, Germany
(e-mail: G.Kulzinger@thphys.uni-heidelberg.de)

Received: 16 June 1998 / Published online: 22 October 1998

We calculate diffractive photo- and leptoproduction of $\rho$-, $\rho'$- and $\rho''$-mesons. The incoming photon dissociates into a $q\bar{q}$-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 $\rho'$- and $\rho''$-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 $\pi^+\pi^-$-invariant mass for photoproduction and e+e--annihilation.

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