Observation of Kappa (730 MeV) Production inπ+pInteractions at 3.2 GeV/c

Abstract

A narrow peak in the $K\pi$ effective-mass spectrum corresponding to the so-called kappa meson has been observed in the reaction ${\pi }^{+}+p\to {\Lambda }^0+K^{+,0\mathrm{}}+{\pi }^{+}+{\pi }^{0,+}$ at 3.2 GeV/c. We have shown that this peak cannot be explained by triangular or box singularity effects.