Angular momentum and generalized parton distributions for the proton with basis light-front quantization

TL;DR

This paper computes the generalized parton distributions for valence quarks in the proton using basis light-front quantization, revealing insights into quark angular momentum distributions and their flavor contributions.

Contribution

It introduces a BLFQ-based method to calculate GPDs and angular momentum densities, highlighting differences in angular momentum definitions within the proton.

Findings

GPDs for valence quarks are successfully computed in momentum and position space.

Different definitions of angular momentum density show notable differences.

Flavor contributions to quark angular momentum densities are analyzed.

Abstract

We study the unpolarized and the helicity dependent generalized parton distributions (GPDs) for the valence quarks of the proton in both momentum space and position space within the basis light-front quantization (BLFQ) framework. The GPDs for the valence quarks are computed from the eigenvectors of a light-front effective Hamiltonian in the valence Fock sector consisting of a three-dimensional confinement potential and a one-gluon exchange interaction with fixed coupling. Employing these GPDs, we obtain the spatial distributions of quark angular momentum inside the proton. In our BLFQ approach, we explore various definitions of angular momentum density and illustrate the differences between them arising from terms that integrate to zero. We also discuss the flavor contributions to the quark angular momentum densities.