Quark intrinsic motion and the link between TMDs and PDFs in covariant approach

TL;DR

This paper explores the connection between transverse momentum dependent distributions (TMDs) and parton distribution functions (PDFs) within a covariant model, emphasizing relativistic symmetry and intrinsic quark motion.

Contribution

It introduces a covariant approach linking TMDs and PDFs based on symmetry principles, providing predictions for polarized and unpolarized TMDs from known PDFs.

Findings

Predictions for polarized TMDs

Predictions for unpolarized TMDs

Relativistic covariance constrains TMD-PDF relations

Abstract

The relations between TMDs and PDFs are obtained from the symmetry requirement: relativistic covariance combined with rotationally symmetric parton motion in the nucleon rest frame. This requirement is applied in the covariant parton model. Using the usual PDFs as an input, we are obtaining predictions for some polarized and unpolarized TMDs.