Determination of flavor asymmetry for $\Sigma^{\pm}$ by the Drell-Yan   process
  Flavor asymmetries for the valence and sea quarks of the $\Sigma^{\pm}$ can be obtained from Drell-Yan experiments using charged hyperon beams on proton and deuteron targets. A large, measurable difference in sea quark asymmetries is predicted between SU(3) and pseudoscalar meson models. The latter predict that in $\Sigma^{+}$, $\bar{u}/\bar{d} \leq 1/2$, whereas the former predict $\bar{u}/\bar{d} \approx 4/3$. Estimates of valence quark asymmetries based on quark models also show large deviations from SU(3) predictions, which should be measurable. 
Mary Alberg, Ernest M. Henley, Xiangdong Ji and A.W. Thomas