Low energy scattering and photoproduction of η-mesons on deuterons
N. V. Shevchenko, V. B. Belyaev, S. A. Rakityansky, S. A. Sofianos, W. Sandhas
Abstract
Photo-production of \eta-mesons and their collisions with light nuclei are studied within the Alt-Grassberger-Sandhas (AGS) formalism for different parameters of \eta N interaction. A three-body resonance or a quasi-bound state is found close to the \eta d threshold. Expected manifestation of this resonant behavior of \eta d elastic scattering in various processes involving \eta d-system in their final states was found in calculations of the \gamma d \to \eta d reaction in the framework of modified AGS equations. These calculations revealed peaks in the energy dependence of the total cross-section almost at the same energies as in the elastic \eta d scattering. Meanwhile, such peaks did not appear in the impulse approximation (i.e. when \eta d resonance was not taken into account). This sheds some light on the nature of the enhancement of \eta photo-production on deuteron observed recently in the low energy experiments.