The role of pion exchange in $\eta$ meson photo production on the deuteron

TL;DR

This paper investigates the impact of pion exchange mechanisms on eta meson photoproduction on deuterons, highlighting the significance of final state interactions and their effects on observable quantities.

Contribution

It introduces a detailed analysis of pion exchange contributions in eta photoproduction, emphasizing their comparable importance to eta-nucleon rescattering effects.

Findings

Pion exchange contributions are comparable to eta-nucleon rescattering effects.

Final state interactions significantly influence polarization observables.

Results provide insights into cross sections and polarization sensitivities.

Abstract

Incoherent $\eta$ photoproduction on the deuteron is studied with the main emphasis on the role of final state interactions. In addition to the previously studied mechanisms of $NN$ and $\eta N$ rescatterings, the role of an intermediate pion exchange is considered in detail, where first a pion is photoproduced on one nucleon and then rescatters into an $\eta$ meson on the other, the spectator nucleon. It is found, that the role of this pion mediated contribution is comparable in size to that of $\eta N$ rescattering. Results for total and semi-inclusive differential cross sections and associated polarization observables are presented. In particular polarization observables show a significant sensititvity to final state interactions.