A Possible Resolution of the Strange Quark Polarization Puzzle ?

Abstract

The strange quark polarization puzzle, i.e. the contradiction between the negative polarized strange quark density obtained from analyses of inclusive DIS data and the positive values obtained from combined analyses of inclusive and semi-inclusive SIDIS data using de Florian et. al. (DSS) fragmentation functions, is discussed. To this end the results of a new combined NLO QCD analysis of the polarized inclusive and semi-inclusive DIS data, using the Hirai et. al. (HKNS) fragmentation functions, are presented. It is demonstrated that the polarized strange quark density is very sensitive to the kaon fragmentation functions, and if the set of HKNS fragmentation functions is used, the polarized strange quark density obtained from the combined analysis turns out to be negative and well consistent with values obtained from the pure DIS analyses.

Figures (4)

• Figure 1: Comparison between polarized strange quark densities obtained from different kinds of NLO QCD analyses (see the text).
• Figure 2: Comparison between NLO HKNS and DSS kaon FFs at $Q^2=10~GeV^2$.
• Figure 3: Comparison of our NLO LSS'11 (black curves) and LSS'10 (red curves) results for the SIDIS asymmetries with the data at measured $x$ and $Q^2$.
• Figure 4: Comparison between NLO LSS'11(HKNS FFs) and LSS'10(DSS FFs) sea quark and gluon polarized PDFs at $Q^2=2.5~GeV^2$. The blue curve corresponds to $x(\Delta s(x)+\Delta \bar{s}(x))/2$ obtained from the pure DIS analysis LSS07.