Cross section asymmetries in vector-meson electroproduction and in inelastic ep scattering with polarized beam and target

The cross-section asymmetries are discussed for forward diffractive vector meson (rho0) production by inelastic scattering of longitudinally polarized electrons (or muons) on polarized protons. Only for the case when both the beam and the target are polarized can considerable effects be expected. On the basis of the off-diagonal GVDM relations between the cross section asymmetries in ep→eprho0 (forward direction) and in ep→eX are given. For a longitudinally polarized target the cross-section asymmetries in ep→eprho0 are predicted to be roughly twice as large as in ep→eX. (Auth.)