Paper
Polarization in diffractive electroproduction of light vector mesons
Authors
D. Yu. Ivanov, R. Kirschner
Abstract
We study in perturbative QCD the helicity ampltiudes of the process at large virtualities of the photon . We estimate all spin flip amplitudes taking into account an important effect of the scale behaviour of the gluon density. The transition of a transverse virtual photon to a longitudinal vector meson is not small at typical HERA conditions. This helicity non-conserving amplitude leads by interference to a measurable effect in the distribution of the angle between the electron scattering and the meson production planes.