
#1
Jun108, 07:31 PM

P: 7

Is weak interaction invaraint under CPT Symmetry? Why?




#2
Jun108, 08:08 PM

Sci Advisor
P: 779

yes it is. it is a theorem that all quantum field theories that satisfy relatively weak conditions (locality, unitarity, Smatrix,...) are CPTinvariant. weak interactions are no exception. you can prove it by referring to that theorem, or by just bruteforce transforming the action under CPT and seeing that it's invariant.




#3
Jun208, 04:26 AM

P: 7

would you please expline further? How can I prove that?




#4
Jun208, 05:21 AM

Sci Advisor
P: 1,664

CPT Symmetry
Proof of the CPT theorem is nontrivial and requires quite a bit of background. But it is a deep and important mathematical truism about quantum field theories.
There are various books that treat it in varying degrees of rigor. I think Weinberg proves it in his volumes, and for a more mathematical treatment see Streeter/Wightman. Incidentally people look for violation of the CPT experimentally, so far without success. But it would be a big deal if one day such a fundamental symmetry was broken. It would mean probably that we would need to go back to Constructive field theories for insight. 


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