Overview of recent HERMES results

The HERMES experiment at DESY, Hamburg, designed to study the spin structure of the nucleon, produced precise results on polarized proton, deuteron and neutron structure functions from measurements of double-spin asymmetries in inclusive deep-inelastic scattering. Reliable hadron identification at HERMES allowed the extraction of the gluon polarization and of flavor-separated quark (anti-quark) helicity distribution functions from analysis of semi-inclusive deep-inelastic scattering data. During the last decade HERMES has extended its program towards understanding multidimensional pictures of the nucleon at the partonic level. These are described by recently developed formalisms of generalized parton distributions and transverse momentum dependent parton distribution functions. Measurements of azimuthal asymmetries in exclusive real photon and meson production processes can constrain generalized parton distributions, while analysis of data on azimuthal asymmetries in semi-inclusive deep-inelastic scattering can provide access to transverse momentum dependent distributions. An overview of recent HERMES results on azimuthal asymmetries measured in deeply virtual Compton scattering, semi-inclusive deep-inelastic scattering, and inclusive hadron electroproduction is presented.