Unified Description of Polarized and Unpolarized Quark Distributions in the Proton

• Published in: Physical review letters Vol. 124; no. 8; p. 082003
• Main Authors: Liu, Tianbo, Sufian, Raza Sabbir, de Téramond, Guy F, Dosch, Hans Günter, Brodsky, Stanley J, Deur, Alexandre
• Format: Journal Article
• Language: English
• Published: United States American Physical Society 28-02-2020; American Physical Society (APS)
• Subjects: Chirality; Hadrons; Holography; Nucleons; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Polarization; Protons; Quarks; Strong interaction; Substructures; Veneziano model
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.124.082003

We propose a unified new approach to describe polarized and unpolarized quark distributions in the proton based on the gauge-gravity correspondence, light-front holography, and the generalized Veneziano model. We find that the spin-dependent quark distributions are uniquely determined in terms of the unpolarized distributions by chirality separation without the introduction of additional free parameters. The predictions are consistent with existing experimental data and agree with perturbative QCD constraints at large longitudinal momentum x. In particular, we predict the sign reversal of the polarized down-quark distribution in the proton at x=0.8±0.03, a key property of nucleon substructure which will be tested very soon in upcoming experiments.