Are valence quarks rotating?

TL;DR

This paper proposes a method to investigate valence quark orbital angular momentum in the proton by comparing deep inelastic scattering structure functions with different proton polarizations, using a proton-ensemble model.

Contribution

It introduces a novel approach to directly probe valence quark orbital angular momentum through polarization-dependent structure function measurements.

Findings

Potential evidence for valence quark rotation effects.

Estimation of the rotating effect using a proton-ensemble model.

Guidance for future experimental investigations.

Abstract

We suggest to compare the deep inelastic scattering structure functions measured in the unpolarized charged-lepton scattering off a transversely polarized proton and off a longitudinally polarized proton at larger Bjorken variable $x$, one may get a direct evidence concerning the valence quark orbital angular momentum in the proton. This possible rotating effect is estimated by using a proton-ensemble model.