Phenomenology of the Lambda/Sigma⁰ production ratio in pp collisions

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We show that the recently measured asymmetry in helicity-angle spectra of the Lambda-hyperons produced in the reaction pp -> K+Lambda p reaction and the energy dependence of the total pp -> K+Lambda p cross section can be explained consistently by the same Lambda p final-state interaction. Assuming that there is no final-state interaction in the Sigma⁰ p channel, as suggested by the available data, we can also reproduce the energy dependence of the Lambda/Sigma⁰ production ratio and, in particular, the rather large ratio observed near the reaction thresholds. The nominal ratio of the Lambda and Sigma⁰ 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.