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

Abstract

Using continuum Schwinger function methods, a coherent set of predictions for proton, $\Lambda$ and ${\Sigma }^0$ 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$(3)$-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 ${\Sigma }^0$, the valence strange quark would carry none of the ${\Sigma }^0$ 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.

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