$\rho$-Meson Form Factors in the Point Form

TL;DR

This paper calculates the electromagnetic form factors of the $ ho^+$ meson using a relativistic quantum mechanics approach, explicitly accounting for photon exchange dynamics and addressing unphysical contributions due to the Bakamjian-Thomas framework.

Contribution

It introduces a point-form relativistic formalism for $ ho$-meson form factors, explicitly incorporates photon exchange, and separates physical from unphysical current contributions.

Findings

Form factors agree with other approaches

Explicit treatment of photon exchange dynamics

Separation of physical and unphysical current contributions

Abstract

We present a calculation of the electromagnetic form factors of the $\rho^+$ meson. Our formalism is based on the point-form of relativistic quantum mechanics. Electron-$\rho$-meson scattering is formulated as a coupled-channel problem for a Bakamjian-Thomas mass operator, such that the dynamics of the exchanged photon is taken explicitly into account. The $\rho$-meson current is extracted from on-shell matrix elements of the optical potential of the scattering process. As a consequence of the violation of cluster separability in the Bakamjian-Thomas framework, our current includes additional, unphysical contributions, which can be separated from the physical ones uniquely. Our results for the form factors are in good agreement with other approaches.