Θ+baryon production inKNandNNreactions

Abstract

We study ${\ensuremath{\Theta}}^{+}(1540)$ production in kaon-nucleon $(\mathrm{KN})$ and nucleon-nucleon $(\mathrm{NN})$ interactions by assuming that the ${\ensuremath{\Theta}}^{+}$ is an isosinglet with ${J}^{P}={\frac{1}{2}}^{+}.$ Possible t-channel diagrams with ${K}^{*}$ exchange are considered in both reactions as well as K exchange in NN reactions. The cross section for $n\stackrel{\ensuremath{\rightarrow}}{p}{\ensuremath{\Lambda}}^{0}{\ensuremath{\Theta}}^{+},$ which has not been considered in previous calculations, is found to be about a factor of 5 larger than that for $n\stackrel{\ensuremath{\rightarrow}}{p}{\ensuremath{\Sigma}}^{0}{\ensuremath{\Theta}}^{+}$ due to the large coupling of the $\mathrm{KN}\ensuremath{\Lambda}$ interaction. The cross sections are obtained by setting ${g}_{\mathrm{KN}\ensuremath{\Theta}}=1$ and varying the ratio of ${g}_{{K}^{*}N\ensuremath{\Theta}}{/g}_{\mathrm{KN}\ensuremath{\Theta}}$ so that future experimental data can be used to estimate these couplings. We also find that the isospin relations hold for these reactions.