Extraction of the Sivers function from SIDIS, Drell-Yan, and $W^\pm/Z$ boson production data with TMD evolution

TL;DR

This paper performs a comprehensive global analysis of polarized SIDIS, Drell-Yan, and W/Z boson production data at high perturbative orders to extract the Sivers function and test its universality and sign-change properties.

Contribution

It introduces a combined fit at N$^3$LO and NNLO accuracy for the Sivers function across multiple processes, including a model-independent determination of the Qiu-Sterman function.

Findings

Successful extraction of the Sivers function for various quark flavors.

Confirmation of the sign-change relation of the Sivers function between SIDIS and Drell-Yan.

Insights into the universality and constraints of the Sivers function.

Abstract

We perform a global fit of the available polarized Semi-Inclusive Deep Inelastic Scattering (SIDIS), polarized pion-induced Drell-Yan (DY) and $W^\pm/Z$ boson production data at N$^3$LO and NNLO accuracy of the Transverse Momentum Dependent (TMD) evolution, and extract the Sivers function for $u$, $d$, $s$ and for sea quarks. The Qiu-Sterman function is determined in a model independent way via the operator product expansion from the extracted Sivers function. The analysis is supplemented by additional studies, such as the estimation of applicability region, the impact of the unpolarized distributions' uncertainties, the universality of the Sivers functions, positivity constraints, the significance of the sign-change relation, and the comparison with the existing extractions