Covariant form factors for spin-1 particles

Abstract

Spin-1 particles, is a fundamental bound state for the two quarks, and play a crucial role in elucidating the electromagnetic properties within the realm of hadronic physics. Their intrinsic relativistic nature mandates a quantum field theory (QFT) framework for a comprehensive analysis. In this investigation, we employ both the instant form of QFT and light-front quantum field theory (LFQFT) as our theoretical tools. While conventional LFQFT approaches predominantly focus on the plus component of the electromagnetic current to extract the properties of spin-1 vector particles, our study extends this analysis by systematically incorporating the minus component as well. Our findings demonstrate that achieving a rigorous equivalence between these distinct current components necessitates the inclusion of nonvalence terms within the electromagnetic current operator. This crucial inclusion serves to restore manifest covariance and ensures a robust consistency with the results independently derived from the more conventional instant form of quantum field theory.