Regge-plus-resonance predictions for kaon photoproduction from the neutron

TL;DR

This paper extends a Regge-plus-resonance model to predict kaon photoproduction from neutrons, comparing predictions with recent experimental data and analyzing the impact of helicity amplitude uncertainties.

Contribution

It adapts a proton-based Regge-plus-resonance model to neutron targets using isospin symmetry and assesses the model's predictive capabilities and limitations.

Findings

The model provides a fair description of neutron kaon photoproduction data.

Uncertainties in helicity amplitudes significantly affect prediction accuracy.

The approach demonstrates the robustness of the Regge model for neutron targets.

Abstract

We present predictions for n(gamma,K+)Sigma- differential cross sections and photon-beam asymmetries and compare them to recent LEPS data. We adapt a Regge-plus-resonance (RPR) model developed to describe photoinduced and electroinduced kaon production off protons. The non-resonant contributions to the amplitude are modelled in terms of K+(494) and K*+(892) Regge-trajectory exchange. This amplitude is supplemented with a selection of s-channel resonance diagrams. The three Regge-model parameters of the n(gamma,K+)Sigma- amplitude are derived from the ones fitted to proton data through SU(2) isospin considerations. A fair description of the n(gamma,K+)Sigma- data is realized, which demonstrates the Regge model's robustness and predictive power. Conversion of the resonances' couplings from the proton to the neutron is more challenging, as it requires knowledge of the photocoupling helicity amplitudes. We illustrate how the uncertainties of the helicity amplitudes propagate and heavily restrain the predictive power of the RPR and isobar models for kaon production off neutron targets.