Half-mission cross spectra for polarized synchrotron emission as evaluated for Planck PR3 (blue) and COSMOGLOBE DR1 (black). Filled circles correspond to E modes, while empty circles correspond to B modes. The thick solid and dashed lines are the best-fit E- and B-mode power law fits to synchrotron, and the thin black line is the Λ cold dark matter prediction for E modes. The lowest bin is not included in either fit.