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تسجيل مستخدم جديدDiffractive photo- and leptoproduction of vector mesons $rho$, $rho$ and $rho$
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We calculate diffractive photo- and leptoproduction of $rho$-, $rho$- and $rho$-mesons. The incoming photon dissociates into a $qbar{q}$-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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In the framework of non-perturbative QCD we calculate high-energy diffractive production of vector mesons $rh, rh$ and $rh$ by real and virtual photons on a nucleon. The initial photon dissociates into a $qbar{q}$-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 $rh$- and $rh$-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 $pi^+pi^-$-mass spectra for photoproduction and $e^+e^-$-annihilation.
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