On the Extraction of Cross Sections for pi0 and eta Photoproduction off Neutrons from Deuteron Data

TL;DR

This paper analyzes how to accurately extract neutral meson photoproduction cross sections off neutrons from deuteron data, emphasizing the role of final-state interaction corrections and their dependence on energy and angle.

Contribution

It provides a detailed examination of FSI correction similarities for pi0 production off protons and neutrons, especially near the Delta resonance, and discusses numerical correction factors and model descriptions.

Findings

FSI corrections for pi0 production are similar for protons and neutrons near the Delta resonance.

Large differences in correction factors occur only at extreme forward angles above the Delta range.

Numerical correction factors for specific reactions are presented and analyzed.

Abstract

We discuss the procedure of extracting the photoproduction cross section for neutral pseudoscalar mesons off neutrons from deuteron data. The main statement is that the final-state interaction (FSI) corrections for the proton and neutron target are in general not equal, but for pi0 production there are special cases were they have to be identical and there are large regions in the parameter space of incident photon energy and pion polar angle, \theta^*, where they happen to be quite similar. The corrections for both target nucleons are practically identical for $\pi_0$ production in the energy range of the Delta(1232)3/2+ resonance due to the specific isospin structure of this excitation. Also above the $\Delta$-isobar range large differences between proton and neutron correction factors are only predicted for extreme forward angles ($\theta^*$ < 20 deg), but the results are similar for larger angles. Numerical results for the gp-->pi0p and gn-->pi0n correction factors are discussed. Also the model description for the available data on the differential gd-->pi0pn cross sections are given.