Probing transverse quark polarization in deep inelastic leptoproduction

The azimuthal dependence of hadrons produced in lepton scattering off a polarized hadron probes the quark transverse-spin distributions. In the calculation of the asymmetries, transverse momenta of quarks in the distribution and fragmentation functions must be incorporated. In addition to the sin(� + �S) asymmetry for transversely polarized hadrons, known as the Collins effect, we find sin2� asymmetries for both transversely and longitudinally polarized hadrons.