Vector meson production and deep-inelastic scattering on (polarized) H-1, H-2, He-3 and N-14 targets

Selected results of diffractive vector meson leptoproduction and inclusive deep-inelastic lepton scattering are presented. The data have been obtained by the HERMES collaboration using polarized H-1,H-2, He-3, and unpolarized N-14 targets that were internal to the HERA 27.5 GeV positron beam. Three copies are addressed: (i) The longitudinal part of the rho(0) production cr oss section is shown to be fairly well described by a pQCD calculation base d on the Off-Forward Parton Distribution (OFPD) framework; (ii) The rho(0) production data reveal a non-zero asymmetry with respect to the spin orient ation of the H-1 target; and (iii) The ratio of inclusive deep-inelastic sc attering data ori N-14 (or He-3) anti H-2 targets shows a surprising deviat ion with respect to existing NMC and E665 data on C-12, which is interprete d in terms of an A-dependence of the quantity R = sigma(L)/sigma(T).