Comparative Regge analysis of $Λ, Σ^0, Λ(1520)$ and $Θ^+$ production in $γp$, $πp$ and $pp$ reactions

Abstract

Using the Quark-Gluon Strings Model -- combined with Regge phenomenology -- we perform a comparative analysis of $Λ$, $Σ^0$, $Λ(1520)$ and $Θ^+$ production in binary reactions induced by photon, pion and proton beams on the nucleon. We find that the existing experimental data on the $γp \to K^+ Λ$ differential and total cross sections can be described very well by the model for photon energies $1 - 16$ GeV and $-t < 2$ GeV$^2$ assuming a dominant contribution of the $K^*$ Regge trajectory. Moreover, using the same parameters we also reproduce the total $γp \to K^+ Σ^0$ and $γp \to K^+ Λ(1520)$ cross sections suggesting a 'universality' of the Regge model. In order to check the consistency of the approach we evaluate the differential and total cross sections for the reaction $π^- p \to K^0 Λ$ which is also found to be dominated by the $K^*$ Regge trajectory. Using the apparent 'universality' of the Regge model we extend our scheme to the analysis of the binary reactions $γp \to \bar{K}^0 Θ^+$, $π^- p \to K^- Θ^+$ and $pp \to Σ^+ Θ^+$ as well as the exclusive and inclusive $Θ^+$ production in the reactions $pp \to p \bar{K}^0 Θ^+$ and $pp \to Θ^+ X$. Our detailed studies demonstrate that $Θ^+$ production does not follow the 'universality' principle thus suggesting an essentially different internal structure of the exotic baryon relative to conventional hyperons or hyperon resonances.