A gauge invariant chiral unitary framework for kaon photo- and electroproduction on the proton

TL;DR

This paper develops a gauge invariant chiral unitary model for kaon photoproduction on protons, analyzing experimental data near threshold and emphasizing the importance of gauge invariance and approximation accuracy.

Contribution

It introduces a gauge invariant framework based on chiral effective Lagrangian and Bethe-Salpeter equation for meson photoproduction, improving upon previous approximation methods.

Findings

Successful analysis of kaon photoproduction data near threshold

Demonstration of the significance of gauge invariance in the model

Assessment of approximation impacts on the interaction kernel

Abstract

We present a gauge invariant approach to photoproduction of mesons on nucleons within a chiral unitary framework. The interaction kernel for meson-baryon scattering is derived from the chiral effective Lagrangian and iterated in a Bethe-Salpeter equation. Within the leading order approximation to the interaction kernel, data on kaon photoproduction from SAPHIR, CLAS and CBELSA/TAPS are analyzed in the threshold region. The importance of gauge invariance and the precision of various approximations in the interaction kernel utilized in earlier works are discussed.