We study the mechanism of the associated Λ-kaon and Σ-kaon production in nucleon-nucleon collisions over an extended range of near-threshold beam energies within an effective Lagrangian model, to understand the new data on $\mathit{pp}\to p\Lambda K^{+}$ and $\mathit{pp}\to p{\Sigma }^0{K}^{+}$ reactions published recently by the COSY-11 Collaboration. In this theory, the hyperon production proceeds via the excitation of $N^{*}(1650),N^{*}(1710)$, and $N^{*}(1720)$ baryonic resonances. Interplay of the relative contributions of various resonances to the cross sections is discussed as a function of the beam energy over a larger near threshold energy domain. Predictions of our model are given for the total cross sections of $\mathit{pp}\to p{\Sigma }^{+}{K}^0,\mathit{pp}\to n{\Sigma }^{+}{K}^{+}$, and $\mathit{pn}\to n\Lambda K^{+}$ reactions.

• Received 3 December 2005

DOI:https://doi.org/10.1103/PhysRevC.73.035211