Strangeness Production Process pp→nK⁺ Σ^ within Resonance Model

We explore production mechanism and final state interaction in the pp→nK^⁺Σ⁺ channel based on the inconsistent experimental data published
respectively by COSY-11 and COSY-ANKE. The scattering parameter a>0 for nΣ⁺ interaction is favoured by large near-threshold cross section within a nonrelativistic parametrization investigation, and a strong n∑⁺ interaction comparable to pp interaction is also indicated. Based on this analysis we calculate the contribution from resonance ∆* (1920) through π⁺ 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 Δ*(1620), the model gives a much better description to the rather large near-threshold total cross section published by COSY-11.