Generalized quasi parton distributions in a diquark spectator model

TL;DR

This paper explores the feasibility of using quasi-GPDs, calculated in a diquark spectator model, as a practical approach to approximate standard GPDs for finite hadron momenta, aiding lattice QCD studies.

Contribution

It extends the concept of quasi-PDFs to generalized parton distributions and analyzes their behavior in a scalar diquark model, highlighting their potential for lattice QCD applications.

Findings

Quasi-GPDs converge to standard GPDs at infinite momentum.

Finite momentum quasi-GPDs approximate standard GPDs with reasonable accuracy.

Results are sensitive to model parameters, affecting the approximation quality.

Abstract

Recently the concept of quasi parton distributions (quasi-PDFs) for hadrons has been proposed. Quasi-PDFs are defined through spatial correlation functions and as such can be computed numerically using quantum chromodynamics on a four-dimensional lattice. As the hadron momentum is increased, the quasi-PDFs converge to the corresponding standard PDFs that appear in factorization theorems for many high-energy scattering processes. Here we investigate this new concept in the case of generalized parton distributions (GPDs) by calculating the twist-2 vector GPDs in the scalar diquark spectator model. For infinite hadron momentum, the analytical results of the quasi-GPDs agree with those of the standard GPDs. Our main focus is to examine how well the quasi-GPDs agree with the standard GPDs for finite hadron momenta. We also study the sensitivity of the results on the parameters of the model. In general, our model calculation suggests that quasi-GPDs could be a viable tool for getting information about standard GPDs.