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

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^ρ~ Sqrt[6] m_ρ. Notably, r_ρ*z_Q^ρ~ r_D*z_Q^D, where r_ρ, r_D are, respectively, the electric radii of the rho-meson and deuteron.

12 pages, 7 figures, 2 tables