T violation 

The discussion of why a nonzero EDM for the neutron violates P and T (and thus CP) is not strictly true: for a spin-1/2 particle the only axis of quantisation  and thus the only well defined direction  is proportional to its spin. Hence, we have to define the EDM d to be along that axis; the term entering the Hamiltonian is -d.E, which is T-odd and P-odd. Acting with T reverses the neutron's spin and thus d; acting with P reverses the direction of E  hence giving rise to the CP violation. (http://arxiv.org/pdf/0709.3100v3) I'm not convinced by the magnetic moment picture painted, and I may well update the page after consulting with my more learned colleagues.  129.67.119.242