Analysis of the low-energy eta NN-dynamics within a three-body formalism

The interaction of an eta -meson with two nucleons is studied within a thre e-body approach. The major features of the eta NN-system in the low-energy region are accounted for by using a s-wave separable ansatz for the two-bod y etaN and NN amplitudes. The calculation is confined to the (J(pi);T) = (0 (-);1) and (1(-);0) configurations which are assumed to be the most promisi ng candidates for virtual or resonant eta NN-states. The eigenvalue three-b ody equation is continued analytically into the nonphysical sheets by conto ur deformation. The position of the poles of the three-body scattering matr ix as a function of the etaN-intcraction strength is investigated. The corr esponding trajectory, starting on the physical sheet, moves around the eta NN three-body threshold and continues away from the physical area giving ri se to virtual eta NN-states. The search for poles on the nonphysical sheets adjacent directly to the upper rim of the real energy axis gives a negativ e result. Thus no low-lying s-wave eta NN-resonances were found. The possib le influence of virtual poles on the low-energy eta NN-scattering is discus sed.