Quark-antiquark asymmetry of helicity distributions in the nucleon sea

Abstract

We study the helicity distributions of light flavor quark-antiquark ($q\overline{q}$) pairs in the nucleon sea. The valence quarks are handled by adopting the light-cone SU(6) quark-spectator-diquark model and the sea $q\overline{q}$ pairs are treated from statistical consideration by introducing the helicity suppression factors ${l}_{q}(x)$ and ${\overline{l}}_{q}(x)$ to parametrize the helicity distributions of q-flavor sea quark and antiquark respectively, while $\mathrm{\ensuremath{\Delta}}{l}_{q}(x)={l}_{q}(x)\ensuremath{-}{\overline{l}}_{q}(x)$ represents a combined effect of helicity contribution due to sea $q\overline{q}$ pairs. From fitting the nucleon polarization asymmetries ${A}_{1}^{N}$ in inclusive deep inelastic scattering processes and the single-spin asymmetries ${A}_{L}^{{W}^{\ifmmode\pm\else\textpm\fi{}}}$ in Drell-Yan type processes, we find a significant asymmetry between the quark and antiquark helicity distributions of the nucleon sea. Therefore the quark-antiquark asymmetry of helicity distributions of nucleon sea $q\overline{q}$ pairs, i.e., $\mathrm{\ensuremath{\Delta}}{q}_{s}(x)\ensuremath{\ne}\mathrm{\ensuremath{\Delta}}{\overline{q}}_{s}(x)$, plays an important role for a comprehensive understanding of the nucleon spin content.

Locations

• Physical review. D/Physical review. D. - View - PDF
• arXiv (Cornell University) - View - PDF
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