Higher-twist effects in QCD, deep inelastic scattering, and the Drell-Yan process

Abstract

Inclusion of specific effects associated with constituent binding in hadronic wave functions is shown to lead to important non-scaling, nonfactorizing 1/Q2 contributions to cross sections for semi-inclusive deep-inelastic scattering, the Drell-Yan process, and other hard scattering reactions. These 1/Q2 higher-twist terms are predicted to be dominant in well defined kinematic regions such as largex and/or largez. The provide angular distributions typical of longitudinally polarized virtual photons andW's, including sin2 θ terms in meson induced Drell-Yan processes and ine+e−→πX, as well as unusual (1−y) terms in deep-inelastic scattering. Calculations are also presented of the quark structure functions of the pionqπ(x, Q2) and for the quark to pion fragmentation functionDπ(z, Q2). Predictions are made for the azimuthal angle dependence of the cross sections for\(\pi N \to \mu {\text{ }}\bar \mu X\) andlN→l′πX.