Low exposure long-baseline neutrino oscillation sensitivity of the DUNE experiment

TL;DR

This paper evaluates DUNE's ability to detect neutrino mass ordering and charge-parity violation, demonstrating significant sensitivity improvements with increased exposure and optimized beam mode strategies.

Contribution

It provides a detailed sensitivity analysis of DUNE for neutrino mass ordering and CP violation, including uncertainties and optimal exposure strategies.

Findings

DUNE can resolve neutrino mass ordering at 3σ with 66 kt-MW-yr exposure.

DUNE can detect CP violation at 3σ for δ_CP = ±π/2 with 100 kt-MW-yr exposure.

Equal beam mode exposure is nearly optimal for sensitivity.

Abstract

The Deep Underground Neutrino Experiment (DUNE) will produce world-leading neutrino oscillation measurements over the lifetime of the experiment. In this work, we explore DUNE's sensitivity to observe charge-parity violation (CPV) in the neutrino sector, and to resolve the mass ordering, for exposures of up to 100 kiloton-megawatt-years (kt-MW-yr). The analysis includes detailed uncertainties on the flux prediction, the neutrino interaction model, and detector effects. We demonstrate that DUNE will be able to unambiguously resolve the neutrino mass ordering at a 3$\sigma$ (5$\sigma$) level, with a 66 (100) kt-MW-yr far detector exposure, and has the ability to make strong statements at significantly shorter exposures depending on the true value of other oscillation parameters. We also show that DUNE has the potential to make a robust measurement of CPV at a 3$\sigma$ level with a 100 kt-MW-yr exposure for the maximally CP-violating values $\delta_{\rm CP}} = \pm\pi/2$. Additionally, the dependence of DUNE's sensitivity on the exposure taken in neutrino-enhanced and antineutrino-enhanced running is discussed. An equal fraction of exposure taken in each beam mode is found to be close to optimal when considered over the entire space of interest.