The proton spin puzzle and depolarization in pp → ΛΛ

We point out that the measurement of target spin depolarization Dnn in the pp → ΛΛ reaction may test dynamical mechanisms invoked to explain the proton spin puzzle revealed by polarized deep-inelastic scattering experiments. In particular, models with negatively polarized ss pairs in the proton wave function predict Dnn < 0, whereas models with positively polarized gluons would predict Dnn > 0.