Unified Description of Polarized and Unpolarized Quark Distributions in the Proton

Understand

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 $x=0.8\pm0.03$, a key property of nucleon substructure which will be tested very soon in upcoming experiments.