English

Helicity Dependent Distribution Functions of the Proton and $\Lambda$ and $\Sigma^0$ Baryons

High Energy Physics - Phenomenology 2026-01-07 v1 High Energy Physics - Experiment High Energy Physics - Lattice Nuclear Experiment Nuclear Theory

Abstract

Using continuum Schwinger function methods, a coherent set of predictions for proton, Λ\Lambda and Σ0\Sigma^0 distribution functions (DFs) has been made available -- both helicity dependent and unpolarised. The results and comparisons between them reveal impacts of diquark correlations and SU(3)(3)-flavour symmetry breaking, some of which are highlighted in this contribution. For instance: in-proton ratios of helicity-dependent/unpolarised valence-quark DFs are presented; it is highlighted that, were it not for the presence of axialvector diquarks in the Σ0\Sigma^0, the valence strange quark would carry none of the Σ0\Sigma^0 spin; and the sign and size of polarised gluon DFs is discussed -- at a scale typical of modern measurements, gluon partons carry roughly 40% of each octet baryon's spin.

Keywords

Cite

@article{arxiv.2601.02587,
  title  = {Helicity Dependent Distribution Functions of the Proton and $\Lambda$ and $\Sigma^0$ Baryons},
  author = {Yang Yu and Peng Cheng and Hui-Yu Xing and Daniele Binosi and Craig D. Roberts},
  journal= {arXiv preprint arXiv:2601.02587},
  year   = {2026}
}

Comments

9 pages, 1 figure. Contribution to the proceedings of the 26th International Symposium on Spin Physics (SPIN25) -- A Century of Spin, 2025 September 22-26, Qingdao Haitian Hotel, Qingdao, Shandong Province, China