General Helicity Formalism for Two-hadron Production in $e^+e^-$ Collisions and the $\Lambda$ Polarizing Fragmentation Function

TL;DR

This paper develops a comprehensive helicity formalism for analyzing two-hadron production in electron-positron collisions, focusing on polarization observables and the polarizing fragmentation function, with implications for future SIDIS experiments.

Contribution

It introduces a complete TMD helicity formalism for two-hadron production, including the polarizing fragmentation function and its extraction from Belle data.

Findings

Complete azimuthal and polarization structure derived

Extraction of the polarizing FF from Belle data discussed

Predictions provided for SIDIS processes at EIC

Abstract

We present the complete structure of the azimuthal dependences and polarization observables for two-hadron production in $e^+e^-$ annihilation processes within a transverse momentum dependent (TMD) approach adopting the helicity formalism. The leading-twist TMD fragmentation functions (TMD-FFs) for spin-1/2 hadrons are fully accounted for. The role of the polarizing FF, together with its extraction from Belle data for the transverse polarization of $\Lambda$'s, are discussed as well. Finally, predictions for SIDIS processes at EIC are presented.