Updated QCD global analysis of single transverse-spin asymmetries I: Extracting $\tilde{H}$, and the role of the Soffer bound and lattice QCD

TL;DR

This paper updates the QCD analysis of single transverse-spin asymmetries by extracting the twist-3 fragmentation function $ ilde{H}$, and examines the influence of lattice QCD and the Soffer bound on the results, highlighting $ ilde{H}$'s importance.

Contribution

First extraction of the twist-3 chiral odd fragmentation function $ ilde{H}$ using SIDIS and proton-proton collision data, incorporating lattice QCD and Soffer bound constraints.

Findings

$ ilde{H}$ is essential for data agreement.

Lattice QCD tensor charge constraints are compatible.

Soffer bound can be integrated into the analysis.

Abstract

We present an update to the QCD global analysis of single transverse-spin asymmetries presented in Cammarota, et al., PRD 102, 054002 (2020) (JAM3D-20). JAM3D-20 simultaneously included transverse momentum dependent and collinear twist-3 observables, both of which are sensitive to quark-gluon-quark correlations in hadrons. In this study we extract for the first time the twist-3 chiral odd fragmentation function $\tilde{H}$ by incorporating the $\sin\phi_s$ modulation data from SIDIS along with its contribution to the single transverse-spin asymmetry in pion production from proton-proton collisions. We also explore the impact of lattice QCD tensor charge calculations and the Soffer bound on our global analysis. We find that both constraints can be accommodated within our results, with $\tilde{H}$ playing a key role in maintaining agreement with the data from proton-proton collisions.