Nucleon electromagnetic form factors with non-local chiral effective Lagrangian

TL;DR

This paper introduces a covariant nonlocal chiral effective Lagrangian approach to calculate nucleon electromagnetic form factors up to 2 GeV$^2$, achieving results consistent with experimental data and enabling high $Q^2$ studies.

Contribution

It develops a gauge-invariant nonlocal Lagrangian framework for nucleon form factors, extending chiral effective theories to higher momentum transfers.

Findings

Form factors match experimental data with a dipole regulator at 0.85 GeV.

Electromagnetic radii and form factor ratios are accurately reproduced.

Method allows exploration of hadron properties at large $Q^2$.

Abstract

The relativistic version of finite-range-regularisation is proposed. The covariant regulator is generated from the nonlocal Lagrangian. This nonlocal interaction is gauge invariant and is applied to study the nucleon electromagnetic form factors at momentum transfer up to 2 GeV$^2$. Both octet and decuplet intermediate states are included in the one loop calculation. Using a dipole regulator with $\Lambda$ around 0.85 GeV, the obtained form factors, electromagnetic radii as well as the ratios of the form factors are all comparable with the experimental data. This successful application of chiral effective Lagrangian to relatively large momentum transfer make it possible to further investigation of hadron quantities at high $Q^2$.