A Possible Resolution of the Strange Quark Polarization Puzzle ?

TL;DR

This paper investigates the strange quark polarization puzzle by analyzing polarized DIS and SIDIS data with different fragmentation functions, showing the polarized strange quark density can be negative when using HKNS functions, resolving previous contradictions.

Contribution

It introduces a new combined NLO QCD analysis using HKNS fragmentation functions, demonstrating the sensitivity of strange quark polarization to these functions and providing a potential resolution to the puzzle.

Findings

Polarized strange quark density is sensitive to kaon fragmentation functions.

Using HKNS fragmentation functions yields a negative strange quark polarization.

Results are consistent with previous pure DIS analyses.

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.