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.

arXiv comment36 pages, 11 figures

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Cited by in corpus (21)

• Snowmass 2021 whitepaper: Proton structure at the precision frontier
• Polarized Antimatter in the Proton from Global QCD Analysis
• 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
• Gluon distributions in the proton in a light-front spectator model
• Nucleon spin decomposition with one dynamical gluon
• Tomography of pions and protons via transverse momentum dependent distributions
• Machine learning-based jet and event classification at the Electron-Ion Collider with applications to hadron structure and spin physics
• Chiral and trace anomalies in Deeply Virtual Compton Scattering
• Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab
• Global analysis of polarized DIS & SIDIS data with improved small-$x$ helicity evolution
• Towards three-dimensional nucleon structures at the Electron-Ion Collider in China: A study of the Sivers function
• Polarized gluon distribution in the proton from holographic light-front QCD
• Parton-shower effects in polarized deep inelastic scattering
• Accessing gluon polarization with high-$P_T$ hadrons in SIDIS
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• Analysis of HERA data with a PDF parametrization inspired by quantum statistical mechanics
• Nucleon Structure from Basis Light-Front Quantization : Status and Prospects
• Precision measurement of the longitudinal double-spin asymmetry for dijet production at intermediate pseudorapidity in polarized $pp$ collisions at $\sqrt{s}$ = 200 GeV
• Effect of symmetry breaking of polarized light sea quarks on the nucleon and nuclear structure functions, and sum rules
• Parton distribution functions and QCD coupling constant from LHC and non-LHC data