Phenomenology of the Lambda/Sigma^0 production ratio in pp collisions
  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 Sigma^0 p channel, as suggested by the available data, we can also reproduce the energy dependence of the Lambda/Sigma^0 production ratio and, in particular, the rather large ratio observed near the reaction thresholds. The nominal ratio of the Lambda and Sigma^0 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. 
A. Sibirtsev, J. Haidenbauer, H.-W. Hammer, U.-G. Mei{\ss}ner