The flavour asymmetry and quark-antiquark asymmetry in the Sigma^+-sea

The sea quark content of the $\Sigma^+$ baryon is investigated using light-cone baryon-meson fluctuation model suggested by Brodsky and Ma. It is found that the $\Sigma^+$ sea is flavour asymmetric ($\dbar > \ubar > \sbar$) and quark-antiquark asymmetric ($q \not= \qbar$). Our prediction for the flavour asymmetry, $\dbar > \ubar > \sbar$, is significantly different from the SU(3) prediction ($\dbar < \ubar < \sbar$), while our prediction for the $d$-$\dbar$ asymmetry is consistent with the SU(3) prediction.