POLARIZATION ASYMMETRY IN HIGH-P-PERPENDICULAR TO INCLUSIVE PRODUCTION

We calculate the asymmetry ALL for scattering of longitudinally polarized protons from a polarized target in an effort to discriminate among constituent models of inclusive high-transverse-momentum hadron and jet production. ALL is defined by ALL=(EdσL+d3p-EdσL-d3p)(EdσL+d3p+EdσL-d3p), where σL+ (σL-) is the pp cross section for the configuration in which the proton helicities are the same (opposite). For inclusive pion production the principal mechanism in the constituent-interchange model is quark-meson scattering, which leads to the prediction ALL=0. However, in several recent models the mechanism for producing high-transverse-momentum pions involves processes such as quark-quark scattering for which it is expected that ALL 0. In the present paper ALL is calculated for inclusive production of pions and jets in the phenomenological effective-gluon model and also in a model based on quantum chromodynamics. Among the important ingredients of such calculations are the distribution functions for quarks in a polarized proton. A new model of these is developed and compared to the most recent SLAC data. It is shown that even in models where ALL 0, the magnitude and sign of ALL depend sensitively on the strong-interaction dynamics and hence can be used to discriminate among models of inclusive production. © 1979 The American Physical Society.