Sensitivity of strange quark polarization to flavor SU(3) symmetry breaking

TL;DR

This paper investigates how the polarization of strange quarks in nucleons is affected by the breaking of flavor SU(3) symmetry using a next-to-leading order QCD analysis of polarized deep inelastic scattering data.

Contribution

It provides a detailed NLO QCD analysis examining the sensitivity of strange quark polarization to SU(3) symmetry breaking in polarized DIS data.

Findings

Strange quark polarization is highly sensitive to SU(3) symmetry breaking.

Inclusion of recent JLAB data refines the understanding of strange quark polarization.

Results highlight the importance of symmetry assumptions in polarized quark density extractions.

Abstract

The polarized strange quark puzzle concerns the fact that the polarized strange quark density extracted from polarized inclusive deep inelastic scattering data is significantly negative, whereas it is zero or slightly positive when extracted from a combined analysis of polarized semi-inclusive and inclusive deep inelastic data. SU(3) flavor symmetry, which, it is generally accepted, is not an exact symmetry, plays an important role in the inclusive analysis, and all the extracted polarized quark densities depend, to some extent, on the level of symmetry breaking introduced. But by far the most sensitive to the breaking is the strange quark density. In this paper we present a NLO QCD analysis of the world data on polarized inclusive DIS data on protons, neutrons and deuterons, including the final JLAB CLAS/EG1b data on the proton and deuteron, and study the sensitivity of the strange quark polarization to the breaking of flavor SU(3).