Lepton number violating effects in neutrino oscillations

TL;DR

This paper develops a perturbation theory for neutrino oscillations that includes lepton number violation, showing how small violations can be enhanced in CP-odd environments and analyzing their effects in two-generation models.

Contribution

It introduces a non-adiabatic perturbation framework for neutrino-antineutrino oscillations with lepton number violation, including analytical solutions and physical interpretations.

Findings

Lepton number violation can be enhanced in CP-odd matter environments.

The perturbation theory can be applied to two-generation models to analyze lepton number violation.

Analytical solutions clarify the nature of lepton number violating effects in neutrino oscillations.

Abstract

We develop a non-adiabatic perturbation theory for oscillations involving an arbitrary number of neutrino and antineutrino species, including the possibility of lepton number violation which we treat as a small effect. We interpret the physics of such an approach for the one generation case by introducing the notion of adiabaticity for neutrino and antineutrino oscillations in analogy to flavor oscillations. We find that in a CP-odd matter environment a small lepton number violation in vacuo can be enhanced. Eventually, we apply the perturbation theory to the two generation case and work out an example for manifestations of lepton number violation, which can be solved both perturbatively as well as analytically thereby further clarifying the nature of the perturbation expansion.