Polarized light-antiquark distributions in a meson-cloud model

Abstract

Flavor asymmetry is investigated in polarized light-antiquark distributions by a meson-cloud model. In particular, rho meson contributions to Delta u-bar - Delta d-bar are calculated. We point out that the g_2 part of rho contributes to the structure function g_1 of the proton in addition to the ordinary longitudinally polarized distributions in rho. This kind of contribution becomes important at medium x (>0.2) with small Q^2 (~1 GeV^2). Including N->rho N and N->rho Delta splitting processes, we obtain the polarized rho effects on the light-antiquark flavor asymmetry in the proton. The results show Delta d-bar excess over Delta u-bar, which is very different from some theoretical predictions. Our model could be tested by experiments in the near future.