How well do we know the gluon polarization in the proton?

Abstract

We perform the first simultaneous global QCD analysis of spin-averaged and spin-dependent parton distribution functions (PDFs), including single jet production data from unpolarized and polarized hadron collisions. We critically assess the impact of SU(3) flavor symmetry and PDF positivity assumptions on the quark and gluon helicity PDFs, and find strong bias from these, particularly on the gluon polarization. The simultaneous analysis allows for the first time extraction of individual helicity-aligned and antialigned PDFs with a consistent treatment of uncertainties.

36 pages, 11 figures

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Cited by in corpus (3)

• Generalized parton distributions through universal moment parameterization: non-zero skewness case
• Towards the determination of the gluon helicity distribution in the nucleon from lattice quantum chromodynamics
• Effect of symmetry breaking of polarized light sea quarks on the nucleon and nuclear structure functions, and sum rules