Role of pion exchange inηmeson photoproduction on the deuteron

Abstract

Incoherent η 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 N N and ηN 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 η 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 ηN 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.

On the extraction of cross sections for π0 and η photoproduction off neutrons from deuteron data

“…Theoretical results of Ref. [16] show visible sensitivity of some polarization observables to ηN and intermediate-pion (πN → ηN) FSI effects, but this issue is beyond the scope of the present paper.…”

“…[16] and references therein), and the FSI effects were found to be important only in the very nearthreshold region. At higher energies, they are quite small [16], except for special kinematic configurations, where the IA contributions are suppressed. Theoretical results of Ref.…”

“…The incoherent η-photoproduction off the deuteron was studied in a number of papers (see Ref. [16] and references therein), and the FSI effects were found to be important only in the very nearthreshold region. At higher energies, they are quite small [16], except for special kinematic configurations, where the IA contributions are suppressed.…”

Low-energy η -nucleon interaction studied with η photoproduction off the deuteron

“…A slight enhancement in the backward direction due to the ηN → ηN rescattering is important for this agreement. Fix et al [20] also have done a comparable calculation, and found a rather minor role of the ηN → ηN rescattering mechanism in the η angular distribution at these energies. The slight underestimation of their results at backward angles ( Fig.…”

“…1; the π-exchange mechanism was considered only in Ref. [20]. However, comparing the elementary amplitudes implemented in the previous models, the DCC model possesses unique and sound features such as: (i) the model describes all the meson-baryon and photoproduction amplitudes relevant to γd → ηpn in a unified manner; (ii) the model generates, by construction, off-shell amplitudes that are wellsuited for working with the Faddeev framework.…”