Elastic Form Factors of Axial-Vector Mesons: A Contact Interaction Exploration

TL;DR

This paper calculates the elastic form factors of axial-vector mesons using a symmetry-preserving contact interaction approach, revealing zero-crossings in electric form factors and the impact of anomalous magnetic moments.

Contribution

It introduces a novel calculation of axial-vector meson form factors with a contact interaction, including effects of anomalous magnetic moments, and compares results with other models.

Findings

Electric form factors cross zero at lower values for axial-vector mesons than vector mesons.

Charge radii decrease as quark mass increases, following a specific hierarchy.

Anomalous magnetic moment significantly affects magnetic and quadrupole moments.

Abstract

We employ a symmetry-preserving treatment of the contact interaction within the coupled for- malism of Schwinger-Dyson and Bethe-Salpeter equations to calculate the elastic form factors of axial-vector mesons. In this study, we present the computation of the charge radii, magnetic mo- ments, and quadrupole moments of axial-vector mesons, including those composed of light quarks, heavy quarks or a light and a heavy quark. Our findings indicate that the electric form factor for axial-vector mesons, like that of vector mesons, crosses zero. Furthermore, this crossing occurs at a lower value for axial-vector mesons than for vector mesons. The results for vector-axial mesons follow a similar hierarchy in charge radii as observed for S, PS, and V mesons, with radii decreasing as the mass of the dressed quarks increases. We also include a term associated with the anoma- lous magnetic moment in the quark-photon vertex. This term has a noticeable impact on both the axial-vector magnetic moment and quadrupole moment, leading to significant percentage changes in their values. We compare our results with those obtained from other models whenever available.