TMD Relations: Insights from a Light-Front Quark-Diquark Model

TL;DR

This paper explores the relations among proton T-even TMDs up to twist-4 using a light-front quark-diquark model, providing new parameterizations, relationships, and inequality insights.

Contribution

It introduces a comprehensive parameterization table for proton TMDs based on helicity, and constructs intra- and inter-twist relationships within the model.

Findings

Multiple expressions of TMDs in terms of proton helicities.

Linear and quadratic TMD relationships at various twist levels.

Inequality relations among TMDs.

Abstract

In this work, we have established the relations between the T-even proton transverse momentum-dependent parton distributions (TMDs) at all twist levels up to twist-4 using the light-front quark diquark model (LFQDM). From the parameterization equations of TMDs, we have found that there are multiple ways by which a particular TMD can be expressed in terms of the helicities of the proton in the initial and final states. For the first time, we have presented a parameterization table that can be applied to the derivation and recognition of proton TMDs based on their helicity. We have constructed the linear and quadratic relationships of TMDs at the intra-twist and inter-twist levels within the same model. We have also looked at the inequality relations that TMDs follow. Additionally, to provide an easy access to the calculations, amplitude matrices have been expressed in the form of TMDs over all the possible helicities of the diquark.