Apparent CPT Violation in Neutrino Oscillation from Dark Non-Standard Interactions

Understand

A natural realization of CPT violation in neutrino oscillation can arise due to the coupling to a light scalar or vector dark matter (DM).

• The dark non-standard interaction (NSI) is associated with the $\gamma_0$ matrix in neutrino's effective propagator and hence corrects the neutrino Hamiltonian as dark matter potential, in the same way as the ordinary matter effect.
• The effect is, however, inversely proportional to the neutrino energy and hence appears as a correction to the neutrino mass squared.
• Due to a sign difference in the corrections for neutrino and anti-neutrino modes, the neutrino oscillation receives CPT violation from the dark NSI.