Transverse Spin Physics at HERMES
  HERMES has measured azimuthal single-spin asymmetries of charged pions produced in deep-inelastic scattering of positrons on a transversely polarised hydrogen target. The presented azimuthal moments provide access to two yet unknown quark distribution functions, the transversity distribution function \delta q and the Sivers function f_{1T}^{perp}. 
A. Hillenbrand (for the HERMES Collaboration)