Strangeness Production Process $pp\to n{K}^{+}{\Sigma }^{+}$ within Resonance Model

Abstract

We explore production mechanism and final state interaction in the $pp\to n{K}^{+}{\Sigma }^{+}$ channel based on the inconsistent experimental data published respectively by COSY-11 and COSY-ANKE. The scattering parameter $a>0$ for $n{\Sigma }^{+}$ interaction is favored by large near-threshold cross section within a nonrelativistic parametrization investigation, and a strong $n{\Sigma }^{+}$ interaction comparable to $pp$ interaction is also indicated. Based on this analysis we calculate the contribution from resonance ${\Delta }^{\ast }(1920)$ through ${\pi }^{+}$ exchange within resonance model, and the numerical result suggests a rather small near-threshold total cross section, which is consistent with the COSY-ANKE data. With an additional sub-threshold resonance ${\Delta }^{\ast }(1620)$, the model gives a much better description to the rather large near-threshold total cross section published by COSY-11.

Comments: 10pp + 4figs, published version