Theta^+ baryon production in KN and NN reactions

Abstract

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

Comments: REVTeX, 13 pages, 8 figures, minor revision, to appear in Phys. Rev. D