Polarized Parton Densities and Higher Twist in the Light of the Recent CLAS and COMPASS data

TL;DR

This paper analyzes recent CLAS and COMPASS data to refine understanding of polarized parton densities and higher twist effects, revealing that low Q^2 data improve higher twist knowledge and high Q^2 data influence strange quark and gluon polarization.

Contribution

It provides a detailed analysis of how recent precise data impact the understanding of polarized parton densities and higher twist corrections in spin structure functions.

Findings

Low Q^2 CLAS data improve higher twist correction estimates.

High Q^2 COMPASS data affect strange quark and gluon polarization.

Current data cannot exclude negative or sign-changing gluon densities.

Abstract

The impact of the recent very precise CLAS and COMPASS g_1/F_1 data on polarized parton densities and higher twist effects is discussed. We demonstrate that the low Q^2 CLAS data improve essentially our knowledge of higher twist corrections to the spin structure function g1, while the large Q^2 COMPASS data influence mainly the strange quark and gluon polarizations which slightly decrease. We find also that the present inclusive DIS data cannot rule out a negative polarized and changing in sign gluon densities.