The helicity-dependent strange quark distribution in the proton, $\mathrm{\Delta }s$, is calculated in a nonlocal chiral SU(3) effective field theory. The hadronic proton to meson plus octet or decuplet baryon splitting functions are derived at the one-loop level, with loop integrals rendered finite by correlation functions introduced in the nonlocal Lagrangian. Within the convolution framework, the proton strange helicity distribution is obtained using spin-flavor symmetry to constrain the input valence quark distributions in the hadronic intermediate states. The polarized strange quark distribution is found to be quite small, with the lowest moment of $\mathrm{\Delta }s$ negative, but consistent with recent global QCD analyses.

• Received 18 March 2022
• Accepted 12 April 2022

DOI:https://doi.org/10.1103/PhysRevD.105.094007

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Published by the American Physical Society