Quark Structure Functions of Mesons and the Drell-Yan Process

Abstract

For massive-lepton pair production in meson-induced reactions, we use quantum chromodynamics perturbation theory to predict that the decay angular distribution in the pair rest frame will change from predominantly $1+{cos}^{2}\ensuremath{\theta}$ to ${sin}^{2}\ensuremath{\theta}$ as the longitudinal-momentum fraction of the pair ${x}_{\mathrm{F}}\ensuremath{\rightarrow}+1$. The two angular distributions are associated respectively with ${(1\ensuremath{-}x)}^{2}$ and ${Q}^{\ensuremath{-}2}{(1\ensuremath{-}x)}^{0}$ components of the valence-quark structure function of the meson.