Pseudoscalar current and covariance with the light-front approach

TL;DR

This paper investigates the pion electromagnetic form factor using light-front quantum field theory, comparing different current components and models to experimental data across various momentum transfer regions.

Contribution

It introduces a detailed analysis of the pseudoscalar current within the light-front approach, highlighting differences from other models and assessing covariance issues.

Findings

The plus and minus current components yield consistent form factors.

Comparison with experimental data shows good agreement at certain momentum transfers.

Differences among models are clarified through covariance considerations.

Abstract

Quantum Field Theory (QFT) is used to describe the physics of particles in terms of their fundamental constituents. The Light-Front Field Theory~(LFFT), introduced by Paul Dirac in 1949, is an alternative approach to solve some of the problems that arise in quantum field theory. The LFFT is similar to the Equal Time Quantum Field Theory~(EQT), however, some particularities are not, such as the loss of covariance in the light-front. Pion electromagnetic form factor is studied in this work at lower and higher momentum transfer regions to explore the constituent quark models and the differences among these and other models. The electromagnetic current is calculated with both the ``plus'' and ``minus'' components in the light-front approach. The results are compared with other models, as well as with experimental data.