Collins Analyzing Power and Azimuthal Asymmetries

Spin azimuthal asymmetries in pion electro‐production in deep inelastic scattering off longitudinally polarized protons, measured by HERMES, are well reproduced theoretically with no adjustable parameters. Predictions for azimuthal asymmetries for a longitudinally polarized deuteron target are given. Using this the z‐dependence of the Collins fragmentation function is extracted for the first time. The first information on e(x) is extracted from CLAS ALU asymmetry.