Reactor Neutrino Spectra

TL;DR

This paper reviews the current understanding of reactor antineutrino spectra, discusses uncertainties in their measurement, and emphasizes the need for new experiments to improve knowledge and address existing anomalies.

Contribution

It provides a comprehensive overview of methods to determine reactor antineutrino spectra and estimates uncertainties, highlighting areas for future experimental improvements.

Findings

Current spectra are derived from electron spectrum conversion or summation methods.

Uncertainties in subdominant beta-decay corrections affect spectrum accuracy.

New experiments are needed to resolve the reactor neutrino anomaly and spectral features.

Abstract

We present a review of the antineutrino spectra emitted from reactors. Knowledge of these and their associated uncertainties are crucial for neutrino oscillation studies. The spectra used to-date have been determined by either conversion of measured electron spectra to antineutrino spectra or by summing over all of the thousands of transitions that makeup the spectra using modern databases as input. The uncertainties in the subdominant corrections to beta-decay plague both methods, and we provide estimates of these uncertainties. Improving on current knowledge of the antineutrino spectra from reactors will require new experiments. Such experiments would also address the so-called reactor neutrino anomaly and the possible origin of the shoulder observed in the antineutrino spectra measured in recent high-statistics reactor neutrino experiments.