Unified Description of Pseudoscalar Meson Structure from Light to Heavy Quarks

TL;DR

This paper reviews a unified algebraic light-front model for pseudoscalar mesons, covering their internal structure and distributions across light to heavy quark regimes, with comparisons to other theoretical approaches.

Contribution

It introduces a comprehensive, symmetry-consistent framework that describes various meson properties from light to heavy quarks using Bethe-Salpeter amplitudes.

Findings

Quark mass increases lead to more symmetric and compact meson structures.

The model provides consistent descriptions of PDAs, GPDs, PDFs, and form factors.

Results align with lattice QCD and Dyson-Schwinger studies where available.

Abstract

We present a comprehensive review of the structure of pseudoscalar mesons within an algebraic model formulated in the light-front framework. The approach provides a unified description of leading-twist parton distribution amplitudes (PDAs), light-front wave functions (LFWFs), generalized parton distributions (GPDs), parton distribution functions (PDFs), elastic electromagnetic form factors (EFFs), charge radii, and impact-parameter GPDs (IPS-GPDs), all derived consistently from the same underlying Bethe-Salpeter amplitudes. Results are discussed for light ($\pi$, $K$), heavy-light ($D$, $D_s$, $B$, $B_s$, $B_c$), and heavy-heavy ($\eta_c$, $\eta_b$) pseudoscalar mesons, allowing for a systematic analysis of the role played by quark-mass asymmetry and heavy-quark dynamics. The study highlights how increasing quark masses drive a transition from broad, asymmetric momentum distributions to increasingly symmetric and spatially compact configurations. Comparisons with lattice QCD, Dyson-Schwinger equation studies, and contact-interaction models are presented where available. Overall, the algebraic model offers a transparent and symmetry-consistent framework to explore the three-dimensional momentum and spatial structure of pseudoscalar mesons across all quark-mass regimes.