Flavor asymmetry of polarized antiquark distributions and semi-inclusive DIS

Abstract

The $1/N_c$-expansion of QCD suggests large flavor asymmetries of the polarized antiquark distributions in the nucleon. This is confirmed by model calculations in the large-$N_c$ limit (chiral quark-soliton model), which give sizable results for $\Delta \bar{u}(x)-\Delta \bar{d}(x)$ and $\Delta \bar{u}(x)+\Delta \bar{d}(x)-2\Delta \bar{s}(x)$. We compute the contributions of these flavor asymmetries to the spin asymmetries in hadron production in semi-inclusive deep-inelastic scattering. We show that the large flavor asymmetries predicted by the chiral quark-soliton model are consistent with the recent HERMES data for spin asymmetries in charged hadron production.

Comments: 21 pages, LaTeX2e, 9 eps figures included