Non-Unitary Neutrino Propagation From Neutrino Decay

Understand

Neutrino propagation in space-time is not constrained to be unitary if very light states - lighter than the active neutrinos - exist into which neutrinos may decay.

• If this is the case, neutrino flavor-change is governed by a handful of extra mixing and "oscillation" parameters, including new sources of CP-invariance violation.
• We compute the transition probabilities in the two- and three-flavor scenarios and discuss the different phenomenological consequences of the new physics.
• These are qualitatively different from other sources of unitarity violation discussed in the literature.