Whirlpools in the Sea: Polarization of Antiquarks in a Spinning Proton

Abstract

We argue that the sea of virtual quark-antiquark pairs in a proton is polarized. Quantum chromodynamics allows a valence quark to emit a gluon which then produces pairs. If the parent quark in this process exhibits a ${\mathrm{}(1-x)\mathrm{}}^3$ behavior as $x\to 1$ then the antiquark with helicity the same as the original quark will have a leading ${\mathrm{}(1-x)\mathrm{}}^5$ distribution. Implications for the counting rules and for polarized Drell-Yan annihilation are discussed.