Neutron-Antineutron Oscillation as a Signal of CP Violation

TL;DR

This paper demonstrates that neutron-antineutron oscillation, under Lorentz and CPT invariance, implies CP violation and baryon number violation, linking it to conditions necessary for baryogenesis.

Contribution

It shows that neutron-antineutron oscillation necessarily involves CP violation and baryon number violation, highlighting a fundamental connection in particle physics.

Findings

Neutron-antineutron oscillation implies CP violation under Lorentz and CPT invariance.

The oscillation is caused by a unique operator in the effective Hamiltonian.

External magnetic fields suppress oscillations without introducing new operators.

Abstract

Assuming the Lorentz and CPT invariances we show that neutron-antineutron oscillation implies breaking of CP along with baryon number violation -- i.e. two of Sakharov conditions for baryogenesis. The oscillation is produced by the unique operator in the effective Hamiltonian. This operator mixing neutron and antineutron preserves charge conjugation C and breaks P and T. External magnetic field always leads to suppression of oscillations. Its presence does not lead to any new operator mixing neutron and antineutron.