Chiral Dynamics of the Polarizing Fracture Functions for Baryon   Production
  The concept of spin-directed momentum provides a useful and restrictive framework for describing dynamical mechanisms that can lead to single-spin observables. The value of this framework can be demonstrated by consideration of the polarizing fracture functions that characterize the production of polarized baryons in the target fragmentation region of semi-inclusive deep inelastic scattering from an unpolarized target. When Bjorken x is chosen large enough to indicate a hard scattering from a valence quark, the fracture function formalism dynamically selects a quark-diquark basis for baryon structure. Attention to sonstituent orbital angular momentum in the formation process and its role in contribution to the transverse momentum of the produced baryon illustrates important aspects of the generation of polarization observables. 
Dennis Sivers