Analysis of the low-energy
NN-dynamics within a three-body formalism
1 Tomsk Polytechnic University, 634034 Tomsk, Russia
2 Institut für Kernphysik, Johannes Gutenberg-Universität Mainz,
D-55099 Mainz, Germany
Received: 27 June 2000
Communicated
by W. Weise
Abstract
The interaction of an -meson with two nucleons is studied within
a three-body approach. The major features of the
-system in
the low-energy region are accounted for by using a s-wave separable
ansatz for the two-body
and NN amplitudes.
The calculation is confined to the
and (1-;0)configurations which are assumed to be the most promising candidates
for virtual or resonant
-states. The eigenvalue three-body
equation is continued analytically into the nonphysical sheets by
contour deformation. The position of the poles of the
three-body scattering matrix as a function of the
-interaction
strength is investigated. The corresponding trajectory, starting on
the physical sheet, moves around the
three-body threshold
and continues away from the physical area giving rise to virtual
-states. The search for poles on the
nonphysical sheets adjacent directly to the upper rim of the real
energy axis gives a negative result. Thus no low-lying s-wave
-resonances were found. The possible influence of
virtual poles on the low-energy
-scattering is discussed.
PACS
13.60.Le Meson production - 21.45.+v Few-body systems - 25.20.Lj Photoproduction reactions
Copyright Società Italiana di Fisica, Springer-Verlag 2000