B Symmetry of parity: Mistake in the experiment?

AI Thread Summary
The discussion centers on the implications of Prof. Chien-Shiung Wu's experiment, which demonstrated that parity is not symmetric by observing electron emissions from Co60 atoms. The confusion arises from the expectation that a mirror should invert the direction of emitted electrons and their spin, similar to how it inverts physical objects. However, participants clarify that the quantum mechanical property of spin differs fundamentally from classical rotation, making the analogy with a fan misleading. The key takeaway is that while classical objects exhibit clear differences under parity transformations, the behavior of quantum particles like those in Wu's experiment does not follow the same rules. Understanding this distinction is crucial for grasping the experiment's significance in demonstrating parity violation.
Whatif42
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According to an experiment of Prof. Chien-Shiung Wu parity is not symmetric. A thought experiment of mine contradicts her well proven theory. Where is my mistake?
Recently I saw this YouTube video from Veritassium about CPT -Symmetry:



In this video an experiment of Prof. Chien-Shiung Wu is presented, which has proven that parity is not symmetric, by observing the emmition of electrons from Co60 atoms with synchronised spin. After thinking about this for a while I am very confused, because either this claim an the results of the experiment are wrong, which I don't want to believe or I have made a fundamental misconception.

The video explains the events in a mirrorworld with a mirror. As explained correctly in the video a mirror does invert the z axis of an object (Min 2.54 in the Video). But why is the emmiting direction of the electrons not inverted as well on the z axis? Respectively the spin mirrorimaged?

Lets take a fan for visualisation and place it in front of a mirror and let's presume as well the spin of the fan resembles the spin of a radioactive Co atom in the experiment and the airstream resembles the emmited electrons.

These "electrons" would always flow in the direction of the mirror. No matter if you are in the mirror or the real world.

If I go further, away from the fan to a more theoretical assumption, from my point of understanding, time moves backwards in the mirrorworld as well. As a result of this, it seems obvious, that spin and particle flow are reversed in such a mirrorworld. The spin would be opposite and the electron would be attracted to the Ni60 and not emmited from the Co60.

I would be very happy, if somebody with more knowledge and a better understanding of this topic could reply and help me solve my problem.

Thank you in advance
 
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Whatif42 said:
lets presume as well the spin of the fan resembles the spin of a radioactive
That’s where you’re going wrong - the quantum mechanical property is called “spin” for historical reasons, but is nothing like the classical rotation of a macroscopic object.

You might want to give the Wikipedia article on this experiment a try: https://en.wikipedia.org/wiki/Wu_experiment
 
There a problem with your analogy, the fan is not invariant under parity, i.e. the "real fan" and the "mirror fan" are different and therefore, if I know the properties of the "real fan" and you send me a video of the fan, I can tell you whether I'm seeing the "real" or the "mirror" fan. This is not true for the spin in the Co atoms, so your analogy doesn't work. And is precisely this difference that is the main point of the experiment.
 

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