We consider near-threshold a0(980)-meson production in πN and NN
collisions. An effective Lagrangian approach with one-pion exchange is applied
to analyze different contributions to the cross section for different isospin
channels. The Reggeon exchange mechanism is also evaluated for comparison. The
results from πN reactions are used to calculate the contribution of the
a0 meson to the cross sections and invariant KKˉ mass distributions
of the reactions pp→pnK+Kˉ0 and pp→ppK+K−. It is found that
the experimental observation of a0+ mesons in the reaction pp→pnK+Kˉ0 is much more promising than the observation of a00 mesons in
the reaction pp→ppK+K−. Effects of isospin violation in the reactions
pN→da0, pd→3He/3Ha0, and dd→4Hea0, which are induced by a0(980)--f0(980) mixing, are also analyzed.Comment: 43 pages, including 16 eps figures, to be bublished in Phys. Atom.
Nucl. (Yad. Fiz.) vol. 65, No. 11 (2002