Covariant form factors for spin-1 particles

TL;DR

This paper develops covariant form factors for spin-1 particles using both instant form and light-front quantum field theory, emphasizing the importance of including nonvalence terms to maintain covariance and consistency.

Contribution

It extends light-front QFT analysis of spin-1 particles by systematically incorporating the minus component of the electromagnetic current, ensuring covariance and consistency with instant form results.

Findings

Inclusion of nonvalence terms restores covariance.

Consistent results between instant form and light-front approaches.

Extended analysis beyond plus component of current.

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.