Electromagnetic properties of the πNN system (III). The γD → pn reaction

Abstract

As in our previous study of real pion photoproduction reactions, we have expanded the deuteron photodisintegration amplitude in terms of the leading diagrams. Above the pion production threshold and in the Δ(1236) resonance region the pion reabsorption amplitude dominates the cross section: a virtual pion is created at one nucleon and is reabsorbed by the other. We have shown that our model provides us with an accurate way to handle this effect, which is closely related to the meson exchange currents. Extending our results to the low energy region, we have got the same agreement with the experimental data as in the earlier more classical calculations. Our model reproduces the available experimental data from threshold up to about E γ = 800 MeV. The sensitivity to the choice of the deuteron wave function as well as the influence of the ϱ-exchange mechanism are discussed.