Non-local Quark Condensates for Nucleon's Sea-quark Distribution

Abstract

The intrinsic small-x quark distribution of the nucleon, which we identify as the sea-quark distribution, is calculated using the QCD sum rule method with nonlocal quark condensates. With nonlocal condensates the vacuum quarks carry a distribution of momenta, which is needed to be consistent with the empirical sea-quark distribution. We find an isospin symmetric sea-quark distribution coming from the vacuum quarks with isospin symmetric condensates 〈: uu :〉 = 〈: dd :〉. We show that the euclidean correlation of the vacuum quarks is crucial to the intrinsic sea-quark distribution, and that monopole-type space-time correlations in the nonlocal quark condensate can provide such momentum distributions of the vacuum quarks. © 1995.