pi- and rho-mesons, and their diquark partners, from a contact interaction

TL;DR

This paper uses a contact interaction model within Dyson-Schwinger equations to analyze the electromagnetic properties of mesons and diquarks, revealing similarities and predicting a zero in the rho-meson form factor at high momentum transfer.

Contribution

It provides a unified Dyson-Schwinger equation framework to compare meson and diquark form factors using a simple contact interaction, enabling predictions at large spacelike-Q^2.

Findings

Similar form factors for related mesons and diquarks.

Prediction of a zero in the rho-meson electric form factor at high Q^2.

Relation between rho-meson and deuteron radii and form factor zeros.

Abstract

We present a unified Dyson-Schwinger equation treatment of static and electromagnetic properties of pseudoscalar and vector mesons, and scalar and axial-vector diquark correlations, based upon a vector-vector contact-interaction. A basic motivation for this study is the need to document a comparison between the electromagnetic form factors of mesons and those diquarks which play a material role in nucleon structure. This is an important step toward a unified description of meson and baryon form factors based on a single interaction. A notable result, therefore, is the large degree of similarity between related meson and diquark form factors. The simplicity of the interaction enables computation of the form factors at arbitrarily-large spacelike-Q^2, which enables us to expose a zero in the rho-meson electric form factor at z_Q^\rho ~ Sqrt[6] m_\rho. Notably, r_\rho*z_Q^\rho ~ r_D*z_Q^D, where r_\rho, r_D are, respectively, the electric radii of the rho-meson and deuteron.