Neutron Oscillations and the Parity Doubling Theorem

We review several aspects of parity and CP violation in the framework of neutron-antineutron oscillations. We focus on the parity doubling theorem, which provides a criterion for neutron oscillation in the general theory with ΔB=2 baryon number-violating interactions. We prove by explicit calculations that the violation of the conventional parity symmetry with P2=1 is the necessary condition for neutron oscillations to happen. While the CP violation is not manifest in the oscillation, it is nevertheless intrinsic to the system, and it is transferred, by the mixing matrix, to the neutron interactions and potentially observable as a contribution to the electric dipole moment.