Why should there be CPT symmetry?

[jetwaterluffy]

A few of the books and magazines I have read talk about maintaining CPT symmetry, but I can't see why it should be the case. What is the evidence, theoretical or experimental, of CPT symmetry?

[Bill_K]

CPT invariance is a rigorous consequence of quantum field theory, assuming only locality and Lorentz invariance. The CPT Theorem is sometimes referred to as Lüder's Theorem. See for example Weinberg, Vol 1, p 245.

[juanrga]

A few of the books and magazines I have read talk about maintaining CPT symmetry, but I can't see why it should be the case. What is the evidence, theoretical or experimental, of CPT symmetry?

From an experimental point of view, violations of CPT have been searched

http://rmp.aps.org/abstract/RMP/v83/i1/p11_1