Wave-packet treatment of neutrino oscillations and its implications on determining the neutrino mass hierarchy

TL;DR

This paper models neutrino oscillations using wave packets, revealing how decoherence and dispersion affect the ability of reactor experiments to determine the neutrino mass hierarchy, especially with larger energy uncertainties.

Contribution

It introduces a wave-packet approach to neutrino oscillations, quantifying how decoherence impacts mass hierarchy sensitivity in reactor experiments.

Findings

Decoherence and dispersion cause damping and phase shifts in oscillation patterns.

Energy uncertainties above 1% significantly reduce hierarchy determination confidence.

Sensitivity drops below 3 sigma with large initial energy uncertainties.

Abstract

We derive the neutrino flavor transition probabilities with the neutrino treated as a wave packet. The decoherence and dispersion effects from the wave-packet treatment show up as damping and phase-shifting of the plane-wave neutrino oscillation patterns. If the energy uncertainty in the initial neutrino wave packet is larger than around 0.01 of the neutrino energy, the decoherence and dispersion effects would degrade the sensitivity of reactor neutrino experiments to mass hierarchy measurement to lower than 3 $\sigma$ confidence level.