Form Factors and Generalized Parton Distributions in Basis Light-Front Quantization

TL;DR

This paper employs Basis Light-Front Quantization to compute form factors and GPDs of positronium, revealing relativistic effects and laying groundwork for hadronic studies.

Contribution

It introduces a BLFQ-based method to calculate form factors and GPDs for bound states, including impact-parameter dependent distributions, in a relativistic framework.

Findings

Calculated elastic form factors and GPDs for positronium.

Visualized fermion density in the transverse plane.

Compared relativistic and non-relativistic results to highlight relativistic effects.

Abstract

We calculate the elastic form factors and the Generalized Parton Distributions (GPDs) for four low-lying bound states of a demonstration fermion-antifermion system, strong coupling positronium ($e \bar{e}$), using Basis Light-Front Quantization (BLFQ). Using this approach, we also calculate the impact-parameter dependent GPDs $q(x, {\vec b_\perp})$ to visualize the fermion density in the transverse plane (${\vec b_\perp}$). We compare selected results with corresponding quantities in the non-relativistic limit to reveal relativistic effects. Our results establish the foundation within BLFQ for investigating the form factors and the GPDs for hadronic systems.