SINGLE-SPIN PRODUCTION ASYMMETRIES FROM THE HARD SCATTERING OF POINTLIKE CONSTITUENTS

When one takes into account the transverse momenta of the constituents in a polarized proton, there exists a kinematic, "trigger-bias," effect in the formulation of the QCD-based hard-scattering model which can lead to single-spin production asymmetries. It seems convenient to represent the coherent spin-orbit forces in a polarized proton by defining an asymmetry in the transverse-momentum distribution of the fundamental constituents. It may then be possible to organize the hard-scattering model so that the kinematic constraints of hard 22 scattering provide the leading contribution at large transverse momentum to asymmetries of the type ANd(hpjet+x), ANd(hpx), where p denotes a transversely polarized proton and "" represents any spinless meson composed of light quarks. This approach provides testable relationships between different asymmetries. © 1990 The American Physical Society.