Single and Double Spin Azimuthal Asymmetries in Semi-Inclusive Pion Electroproduction

The leading and sub-leading order results for pion electroproduction in polarized and unpolarized semi-inclusive deep-inelastic scattering, are considered putting emphasis on transverse momentum dependent effects appearing in azimuthal asymmetries. In particular, single-, and double-spin asymmetries of the distributions in the azimuthal angle φ of the pion related to the lepton scattering plane are discussed. A possibility to measure spin-independent and double-spin analyzing powers, simultaneously, is also discussed.