THE PROTON SPIN PUZZLE AND DEPOLARIZATION IN $\bar{p}p\to \bar{\mathrm{\Lambda }}\mathrm{\Lambda }$

We point out that the measurement of target spin depolarization $D_{nn}$ in the $\bar{p}p\to \bar{\mathrm{\Lambda }}\mathrm{\Lambda }$ reaction may test dynamical mechanisms invoked to explain the proton spin puzzle revealed by polarized deep–inelastic scattering experiments. In particular, models with {\it negatively} polarized $\bar{s}s$ pairs in the proton wave function predict $D_{nn}<0$, whereas models with {\it positively} polarized gluons would predict $D_{nn}>0$.