Comparisons and Combinations of Reactor and Long-Baseline Neutrino Oscillation Measurements

TL;DR

This paper analyzes how combining reactor and long-baseline neutrino experiments can improve the measurement of neutrino oscillation parameters, resolve degeneracies, and identify conditions for discovering CP violation and mass hierarchy.

Contribution

It provides a comprehensive analysis of how combined experimental data can enhance parameter constraints and resolve degeneracies in neutrino oscillation measurements.

Findings

Combination of experiments can resolve key degeneracies.

Enhanced flux improves sensitivity to CP violation.

Large sin^2(2θ13) is necessary for measurable effects.

Abstract

We investigate how the data from various future neutrino oscillation experiments will constrain the physics parameters for a three active neutrino mixing model. The investigations properly account for the degeneracies and ambiguities associated with the phenomenology as well as estimates of experimental measurement errors. Combinations of various reactor measurements with the expected J-PARC (T2K) and NuMI offaxis (Nova) data, both with and without the increased flux associated with proton driver upgrades, are considered. The studies show how combinations of reactor and offaxis data can resolve degeneracies (e.g. the theta23 degeneracy) and give more precise information on the oscillation parameters. A primary purpose of this investigation is to establish the parameter space regions where CP violation can be discovered and where the mass hierarchy can be determined. It is found that such measurements, even with the augmented flux from proton driver upgrades, demand sin^2 (2 theta13) be fairly large and in the range where it is measurable by reactor experiments.