Flavor asymmetry in hyperons and Drell-Yan processes

SU(3), baryon octets and a meson cloud model are compared for the flavor asymmetry of sea quarks in the $\Sigma^+$, as an example. Large differences are found, especially between SU(3) and the meson cloud model. We suggest Drell-Yan measurements of $\Sigma^{+}-p$ and $\Sigma^{+}- d$ to test the prediction of various models. We use the meson cloud model to predict both valence and sea quark distributions.