Neutrino Flavor Mixing and Oscillations in Field Theory

TL;DR

This paper analyzes the field-theoretic formulation of neutrino flavor mixing, revealing that the standard Lagrangian describes mixed flavor states but only accurately models oscillations in the ultra-relativistic limit.

Contribution

It provides a complete field theory analysis of the neutrino Lagrangian, clarifying the role of mass matrix elements and flavor states in neutrino oscillation phenomenology.

Findings

Mass matrix elements are field strength renormalization constants.

Flavor states are directly related to one-particle energy states.

Standard Lagrangian describes mixed flavor states but only in the ultra-relativistic limit.

Abstract

The Lagrangian that is normally associated with Dirac neutrinos is analyzed in a complete and simple way through field theory. It is found that the elements of the neutrino mass matrix are field strength renormalization constants and that the flavor fields can be directly applied to the one-particle energy states through these rescaling factors. Moreover this Lagrangian describes neutrinos which are in a state of mixed flavor at any space-time point and therefore does not describe the phenomenology of neutrino oscillations properly, except in the ultra-relativistic limit where such a description is possible.