Normalized histograms of Δ_s(ψ₃₅₃, ψ₂₁₇) for the all, control, and target1 samples in black, blue, and orange, respectively. CMB has been subtracted from the PR3 maps using smica. The shaded area results from the propagation of observational uncertainties in Q_ν and U_ν down to the computation of Δ_s(ψ₃₅₃, ψ₂₁₇). The shaded areas mark the plus and minus one standard deviation around the means obtained in each bin of width 2° through the MC simulations. Continuous lines show the means of the three samples.