Eur. Phys. J. A (2006) 29: 363-367
https://doi.org/10.1140/epja/i2006-10097-5

Hadron Physics

Phenomenology of the Λ/Σproduction ratio in pp collisions

¹ Helmholtz-Institut für Strahlen- und Kernphysik (Theorie), Universität Bonn, Nußallee 14-16, D-53115, Bonn, Germany
² Institut für Kernphysik (Theorie), Forschungszentrum Jülich, D-52425, Jülich, Germany

^* e-mail: j.haidenbauer@fz-juelich.de

Received: 9 August 2006
Accepted: 7 September 2006
Published online: 25 September 2006

Abstract

We show that the recently measured asymmetry in helicity-angle spectra of the Λ-hyperons, produced in the reaction pp → K ⁺Λp reaction, and the energy dependence of the total pp → K ⁺Λp cross-section can be explained consistently by the same Λp final-state interaction. Assuming that there is no final-state interaction in the Σ⁰ p channel, as suggested by the available data for the reaction pp → K ⁺Σ⁰ p, we can also reproduce the energy dependence of the Λ/Σ⁰ production ratio and, in particular, the rather large ratio observed near the reaction thresholds. The nominal ratio of the Λ and Σ⁰ production amplitudes squared, i.e. when disregarding the final-state interaction, turns out to be about 3, which is in line with hyperon production data from proton and nuclear targets available at high energies.