Coherence of neutrino flavor mixing in quantum field theory

TL;DR

This paper uses a quantum field theoretical approach to analyze neutrino flavor mixing, providing a more fundamental understanding of coherence conditions and their impact on observable interference effects.

Contribution

It introduces a fully normalized, time-dependent $S$-matrix framework that naturally reveals neutrino coherence conditions without ad hoc assumptions.

Findings

Reveals coherence conditions in a self-contained manner

Quantitatively describes the transition to loss of coherence

Provides a more fundamental analysis compared to quantum mechanics

Abstract

In the simplistic quantum mechanical picture of flavor mixing, conditions on the maximum size and minimum coherence time of the source and detector regions for the observation of interference---as well as the very viability of the approach---can only be argued in an ad hoc way from principles external to the formalism itself. To examine these conditions in a more fundamental way, the quantum field theoretical $S$-matrix approach is employed in this paper, without the unrealistic assumption of microscopic stationarity. The fully normalized, time-dependent neutrino flavor mixing event rates presented here automatically reveal the coherence conditions in a natural, self-contained, and physically unambiguous way, while quantitatively describing the transition to their failure.