The amplitudes of the circular dichroism (at k summed up to see the actual residual) are reported for both spin-integrated and spin-resolved measurements. The data show that the spin-integrated signal (grey curve) shows a finite value as large as 10% (which is also similar to the experimental uncertainty of 8%, as shown in ref. 39 ), but the spin-resolved channels show a notably larger amplitude, by a factor of 2 and 3 for up and down channels, respectively. The amplitude values have been extracted from the data shown in a and b and in Extended Data Fig. 3 , after including the Sherman function and calculating the true spin polarization, as described in Methods . The other indicated k points, as well as the dichroic amplitude in terms of the momentum distribution curve, are shown in Extended Data Figs. 4 and 5 , and corroborate the validity of our result.
