Parton Distributions for the Octet and Decuplet Baryons

TL;DR

This paper computes the parton distributions for octet and decuplet baryons using the MIT bag model with meson dressing, revealing significant deviations from traditional symmetry predictions and implications for baryon polarization.

Contribution

It introduces a method to calculate polarized and unpolarized parton distributions for baryons considering meson cloud effects and hyperfine interactions, highlighting deviations from SU(3) and SU(6) symmetries.

Findings

Hyperfine interactions cause large deviations from symmetry predictions.

Significant polarized non-strange distributions in the Lambda baryon.

Meson cloud effects lead to flavor symmetry violations.

Abstract

We calculate the parton distributions for both polarized and unpolarized octet and decuplet baryons, using the MIT bag, dressed by mesons. We show that the hyperfine interaction responsible for the $\Delta - N$ and $\Sigma^0 - \Lambda$ splittings leads to large deviations from SU(3) and SU(6) predictions. For the $\Lambda$ we find significant polarized, non-strange parton distributions which lead to a sizable $\Lambda$ polarization in polarized, semi-inclusive $ep$ scattering. We also discuss the flavour symmetry violation arising from the meson-cloud associated with the chiral structure of baryons.