The flavour asymmetry of polarized anti-quarks in the nucleon

Abstract

We present a study of the flavour asymmetry of polarized anti-quarks in the nucleon using the meson cloud model. We include contributions both from the vector mesons and the interference terms of pseudoscalar and vector mesons. Employing the bag model, we first give the polarized valence quark distribution of the $\rho$ meson and the interference distributions. Our calculations show that the interference effect mildly increases the prediction for \Delta \dbar(x)-\Delta \ubar(x) at intermediate $x$ region. We also discuss the contribution of `Pauli blocking' to the asymmetry.Comment: 22 pages, LaTex, 5 PS figures. Version to appear in Eur. Phys. J. C. An appendix is added for expressions for the helicity dependent fluctuation functions. An error in the programme for fluctuation function f_{(\pi\rho)\Delta /N} is corrected, which increases numerical results by about 10%. Unchanged conclusion