Single Transverse-Spin Asymmetry in $pp^\uparrow \to \pi X$ and $ep^\uparrow \to \pi X$

Abstract

Cross section formulas for the single spin asymmetry in $p^\uparrow p\to \pi(\ell_T)X$ and $e p^\uparrow \to \pi(\ell_T)X$ are derived and its characteristic features are discussed.