Hybrid model calculation of light flavor asymmetry in the proton sea

Our hybrid model includes both perturbative and non-perturbative contributions to the $\bar{d}$ and $\bar{u}$ distributions in the proton sea. The non-perturbative contribution is described by a meson cloud model which includes a Fock state expansion of the proton in terms of meson-baryon pairs. The perturbative contribution is described by a statistical model which uses Fock states of quarks, antiquarks and gluons to represent the parton distributions of the ``bare'' hadrons in the meson cloud. We compare our results to the E866 data for $\bar{d}(x)-\bar{u}(x)$ and $\bar{d}(x)/\bar{u}(x)$.