Quark Structure Functions of Mesons, Fragmentation Functions, Higher-Twist Effects in QCD, Deep Inelastic Scattering, and the Drell-Yan Process

摘要

Inclusion of specific effects associated with constituent binding in hadronic wave functions is shown to lead to important nonscaling, nonfactorizing 1/Q exp 2 contributions to cross sections for semi-inclusive deep-inelastic scattering, the Drell-Yan process, and other hard scattering reactions. These 1/Q exp 2 higher-twist terms are predicted to be dominant in well defined kinematic regions such as large x and/or large z. They provide angular distributions typical of longitudinally polarized virtual photons and W's, including sin exp 2 theta terms in meson induced Drell-Yan processes and in e exp + e exp - implies pi X, as well as unusual (1-y) terms in deep-inelastic scattering. Calculations are also presented of the quark structure functions of the pion q/sub pi /(x,Q exp 2 ) and for the quark to pion fragmentation function D/sub pi (z,Q exp 2 ). Predictions are made for the azimuthal angle dependence of the cross sections for pi N implies mu anti mu X and lN implies l' pi X. (ERA citation 04:057295)