Sunday, October 12, 2014

fermions - Does charge conjugation affect parity?



Notice that these transformations do not alter the chirality of particles. A left-handed neutrino would be taken by charge conjugation into a left-handed antineutrino, which does not interact in the Standard Model. --http://en.wikipedia.org/wiki/C-symmetry



The excerpt above seems to unambiguously answer this question. But, then:



You can easily convince yourself (exercise II.1.9) that the charge conjugate of a left handed field is right handed and vice versa. --Quantum Field Theory in a Nutshell, A. Zee




These statements appear to be contradictory. What's going on here?


Also, it does seem easy to convince myself of Zee's comment (following Zee's convention that ψψc=γ2ψ):


Suppose ψ is left-handed (i.e. PLψ=ψ and PRψ=0), then


PLψc=PLγ2ψ=γ2PRψ=γ2(PRψ)=0


and


PRψc=PRγ2ψ=γ2PLψ=γ2(PLψ)=ψc .


Therefore, it appears that Zee's comment is correct. Can anyone help me understand why the two quotes above are or are not in contradiction?




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