The relation between TMDs and PDFs in the covariant parton model approach

TL;DR

This paper derives relations between TMDs and PDFs within a covariant parton model, predicting the detailed momentum dependencies of TMDs based on known PDFs, grounded in Lorentz invariance and rotational symmetry.

Contribution

It introduces a covariant approach linking TMDs and PDFs, providing explicit predictions for TMDs from known PDFs using fundamental symmetry principles.

Findings

Predicted x- and pT-dependence of twist-2 T-even TMDs

Derived relations based on Lorentz invariance and rotational symmetry

Established a framework connecting PDFs and TMDs

Abstract

We derive relations between transverse momentum dependent distribution functions (TMDs) and the usual parton distribution functions (PDFs) in the 3D covariant parton model, which follow from Lorentz invariance and the assumption of a rotationally symmetric distribution of parton momenta in the nucleon rest frame. Using the known PDFs f_1(x) and g_1(x) as input we predict the x- and pT-dependence of all twist-2 T-even TMDs.