Twist-3 Gluon Fragmentation Contribution to the Polarized Hyperon Production in Unpolarized Proton–Proton Collision

We study transverse polarization of hyperons produced in unpolarized proton–proton collision, pp → Λ^↑X, based on the collinear twist-3 factorization. We focus on the twist-3 gluon fragmentation contribution to this process, which is potentially as important as the previously calculated contributions from the twist-3 distribution in the initial proton and the twist-3 quark-fragmentation for Λ^↑. After summarizing the complete set of the purely gluonic twist-3 fragmentation functions for Λ^↑, we provide a formalism of calculating its contribution to pp → Λ^↑X.