Polarized Semi-Inclusive Deep-Inelastic Scattering at $\mathcal O(\alpha_s^3)$ in QCD
Unraveling the partonic origin of the proton spin requires precise determinations of polarized parton distribution functions (PDFs), which depend on comparably precise theoretical predictions for polarized scattering, particularly in view of the high-precision measurements anticipated at the future Electron-Ion Collide...