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## Main Question or Discussion Point

I'm trying to get my head around the cobalt-60 beta decay experiment that apparently was used to show the weak decay did not conserve parity. It basically has a bunch of cobalt nuclei at low temperature in a magnetic field so that their spins are all aligned parallel to the field. The experiment was apparently looking to see whether there was "spatial asymmetry", which I take it means that more beta-electrons would be emitted in one direction relative to the field direction that another.

I get that spin, being an axial vector, won't change direction under the parity operation, r transforming to -r, and that momentum vectors will. I also get that if you saw particles emitted predominantly in one direction, you would see the mirror image as having them being emitted in the opposite direction, but the spin vector direction would be the same in both the mirror and the real world.

what I don't get is what this says about parity violation? I mean, for an eigenstate x, for even parity we have Px = +x, and for odd parity we have Px = -x. Where is the connection between seeing the difference in momentum vector direction in a mirror reflection, and having the parity eigenvalue go from +1 to -1?

The textbooks talk abotu the weak force being able to "distinguish right and left" and therefore this means parity is not conserved, but I just do not understand this.

I get that spin, being an axial vector, won't change direction under the parity operation, r transforming to -r, and that momentum vectors will. I also get that if you saw particles emitted predominantly in one direction, you would see the mirror image as having them being emitted in the opposite direction, but the spin vector direction would be the same in both the mirror and the real world.

what I don't get is what this says about parity violation? I mean, for an eigenstate x, for even parity we have Px = +x, and for odd parity we have Px = -x. Where is the connection between seeing the difference in momentum vector direction in a mirror reflection, and having the parity eigenvalue go from +1 to -1?

The textbooks talk abotu the weak force being able to "distinguish right and left" and therefore this means parity is not conserved, but I just do not understand this.