Strangeness production in proton-proton collisions

The cross sections of the reaction $pp \to N K Y$ for $K^+$ or $K^0$ mesons and $\Lambda$ or $\Sigma$ hyperons are calculated within the boson exchange model including pion and kaon exchange diagrams. We analyze the dependence of the results on the accuracy of the input $\pi N$ amplitude. By fixing the $\pi NN $ coupling constant and the cut-off parameter ${\Lambda}_{\pi}$ at the $\pi NN$ vertex we calculate the contribution from the kaon exchange diagram and obtain the ratio of the $KN \Lambda $ and $KN \Sigma $ coupling constants by a fit to the experimental data. This ratio is in a good agreement with the SU(6) prediction. Our calculated total cross sections for the different reaction channels are fitted by simple expressions and compared with other parameterizations used in the literature. Furthermore, the gross features of the production cross section close to threshold are discussed.