Probing transverse quark polarization in deep-inelastic leptoproduction

The azimuthal dependence of hadrons produced in lepton scattering off a polarized hadron probes the quark transversespin 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(φ + φs) asymmetry for transversely polarized hadrons, known as the Collins effect, we find a sin(3φ − φs) asymmetry. Furthermore, we find a sin2φ angular dependence for longitudinally polarized hadrons.