Flavor asymmetry of polarized and unpolarized sea quark distributions in the large-Nc limit

الأصل · EN

We summarize recent attempts to calculate the flavor asymmetry of the nucleon's sea quark distributions in the large-Nc limit, where the nucleon can be described as a soliton of an effective chiral theory. We discuss the leading-twist longitudinally polarized and transversity antiquark distributions, Δ u (x) - Δ d (x) and δ u (x) - δ d (x), as well as the unpolarized one, u (x) - d (x), which appears only in the next-to-leading order of the 1/Nc-expansion. Results for u (x) - d (x) are in good agreement with the recent Drell-Yan data from the FNAL E866 experiment. The longitudinally polarized antiquark asymmetry, Δ u (x) - Δ d (x), is found to be larger than the unpolarized one.