Chiral and flavor oscillations in quantum field theory

TL;DR

This paper develops a quantum field theory framework to analyze combined chiral and flavor oscillations in massive fermions, revealing a complex vacuum structure and reproducing known oscillation formulas.

Contribution

It introduces a quantum field theory approach to flavor-chiral oscillations, unifying the treatment of these phenomena and analyzing the vacuum structure.

Findings

Reproduces known oscillation formulas within QFT

Discovers a condensate structure in the chiral-flavor vacuum

Provides a unified QFT framework for flavor and chiral oscillations

Abstract

Massive fermions produced through weak charged interactions possess a definite chirality, which is not conserved during free propagation, leading to chiral oscillations. Neutrinos also exhibit flavor oscillations. These phenomena have been extensively studied - both individually and within a unified framework - using the first quantization approach, but only separately in the context of quantum field theory. In this work, we address this gap by developing a quantum field theory treatment of flavor-chiral oscillations. Focusing on the case of two-flavor mixing, we compute the expectation values of the (non-conserved) chiral-flavor charges and recover the same oscillation formulas obtained in the first quantization formalism. These charges are diagonalized via Bogoliubov transformations in both the chiral and flavor sectors. Such transformations reveal a non-trivial structure of the chiral-flavor vacuum, which consists of a condensate of particles with definite masses and helicities.