CP symmetry combines swapping matter for antimatter with a mirror reversal of space. Experiments on the weak interaction showed that even this combined transformation does not always preserve the same behavior.
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19:54well. 1964, the famous 1964 discovery of CP violation. Yes, this is the second layer to the parody violation stuff that we were worried about in that first lecture and we had a huge deep dive in the um Chenning episode last year. The idea of par violation is is the universe symmetric in the mirror? Is the universe the exact same in the mirror? Turns out it's not because the universe can tell whether um I'm left or right based on whether the thing that is shooting out of the nucleus is an electron or an anti-electron. So perhaps antimatter >> and parody are together a symmetry.
20:37That's the next idea, right? It's like what if I what if I flipped everything in the universe >> from left to right, but I also flipped all of the matter to antimatter. then would the universe not be able to tell the difference? That was called CP symmetry. This experiment showed a violation of that symmetry as well. So, it showed that antimatter and matter are really not the same thing. >> Um, this was James Cronin and Val Fitch. They were working at Brook Haven while employed at Princeton University. So, they were professors there. Um, and they demonstrated that the weak interaction violates charge parody symmetry. Won them the 1980 Nobel Prize in Physics. These are some of my most favorite
21:18episodes. The uh the Chenning Yang Yang Mills episode and these ideas of >> symmetries are are really really deep philosophical as well as grounded scientific things. It's fascinating. Uh 1964 prediction of the cosmic microwave background, the CMB.