Rules of Parity and Charge Conjugation Parity

[1Kris]

I have two related questions to ask relating to statements found in introductory particle physics textbooks.

The first is that the "Dirac equation predicts fermions/anti-fermions have opposite intrinsic parity".
I have attempted to verify this by applying the parity transformation to free particle Dirac spinors using an explicit choice of representation. I find that it is true provided the particles are at rest but otherwise, they are not in a state of definite parity. This doesn't seem consistent with the quotation.

The second statement is that "fermion-antifermion pairs with total orbital angular momentum number L and total spin S, have a parity factor (-1)^(L+S) when interchanged". There is some reference to a minus sign appearing upon the interchange of antifermion with fermion which I have not been able to justify. Could anyone show me a detailed explanation of this factor please?

Thanks

 

[Bill_K]

I find that it is true provided the particles are at rest but otherwise, they are not in a state of definite parity.

That's correct.