Assessing signals of TMD physics in SIDIS azimuthal asymmetries and in the extraction of the Sivers function

TL;DR

This paper analyzes recent high-precision SIDIS data from COMPASS to extract the Sivers function, assessing TMD signals and uncertainties across different kinematic regions to improve understanding of nucleon spin structure.

Contribution

It provides a new extraction of the Sivers function using updated data and a simple parametrization, critically evaluating TMD signals and uncertainties.

Findings

Signals of TMD effects are identified in the Sivers asymmetries.

Uncertainties in the Sivers function are thoroughly analyzed across kinematic regions.

The extraction improves understanding of the nucleon spin structure.

Abstract

New data on the Sivers azimuthal asymmetry measured in semi-inclusive deep-inelastic scattering processes have recently been released by the COMPASS Collaboration at CERN. Their increased precision and their particular binning, in terms of $Q^2$ as well as $x$, motivates a new extraction of the Sivers function, within the framework of a simple and transparent parametrization. Signals of TMD effects visible in the Sivers asymmetries are critically assessed. A thorough study of the uncertainties affecting the extracted Sivers function is presented, including the low-$x$ and large-$x$ regions.