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

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 $⟨r^2⟩$, 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.

Comments: 8 pages, 6 figures