The $\rho$-meson electromagnetic form factors within the light-front quark model

TL;DR

This study calculates the electromagnetic form factors of the rho meson using a light-front quark model, revealing insights into relativistic effects, zero-mode contributions, and the internal structure of spin-1 particles.

Contribution

The paper introduces a refined method within the light-front quark model to accurately compute rho meson form factors, addressing zero-mode effects and angular condition violations.

Findings

Zero-mode contribution to matrix element $S_{00}^+$ is zero with type-II replacement.

The 'M→M₀' replacement improves angular condition consistency.

Relativistic effects are weaker in the zero-binding limit.

Abstract

In this paper, we study the $\rho$-meson electromagnetic form factors (EMFFs) within the framework of light-front quark model (LFQM). The physical form factors $G_{C,M,Q}(Q^2)$ of $\rho$-meson as well as the charged square radius $\langle r^2\rangle$, the magnetic moment $\mu$ and the quadrupole moment $\bar Q$ are calculated, which describe the behaviors of EMFFs at zero momentum transfer. Using the type-II replacement, we find that the zero-mode does contribute zero to the matrix element $S_{00}^+$. It is found that the ``$M\to M_{0}$" replacement improves angular condition remarkably, which permits different prescriptions of $\rho$-meson EMFFs give the consistent results. The residue tiny violation of angular condition needs other explanations than the zero-mode contributions. Our results indicate that the relativistic effects or interaction internal structure are weaken in the zero-binding limit. This work is also applied for the other spin-1 particles.