  Within the framework of the recently introduced multi-nanoparticle
power-series expansion method for the polarized small-angle neutron scattering
(SANS) cross section, we present analytical expressions for the polarized SANS
observables arising from dilute nanoparticle assemblies with antisymmetric
vortex-type spin structures. We establish connections between the magnetic
correlation coefficients and the magnetic field-dependent vortex-axes
distribution function, which is related to the random orientations of the
magnetocrystalline anisotropy axes of the nanoparticles. Our analytical results
are validated through a comparative analysis with micromagnetic simulations.
This framework contributes to a comprehensive understanding of polarized
magnetic neutron scattering from spherical nanoparticle systems exhibiting
vortex-type spin structures.
