Gray shaded regions: one and two sigma deviations around the expected value (black horizontal line), assuming a uniform distribution of Δ_S/V angles. The different lines refer to the different values of the FWHM used to evaluate the R_P/p polarization ratio. They represent the ⟨cos(Δ_S/V⟩ values from the data as a function of the fraction of the sample that is gradually removed while decreasing the R_P/p selection threshold.